2008 ~ Severe Plains

Wednesday, December 31, 2008

Iowa 2008: A Weather Review

While I was present throughout much of this year's weather that occurred throughout the state of Iowa, it was helpful to read through some of these great products that the Des Moines National Weather Service has issued over the past couple of days. It will remind you of the bitter cold that was endured in January and February, which also coincided with one of the snowiest February's on record for the state. These events led into a very active spring, it started dry for March and quickly turned to a very wet April. A break in the rain for mid-May would only help the farmers get their crop in the fields, as the latter half of May led to the destructive and national news headlines of the Parkersburg, IA tornado. The state wouldn't stay out of the national spotlight for too long, as the floods across much of Iowa would once again enter during the month of June. Tornadoes would once again lead to national news headlines for the state of Iowa, as on June 11th several boy scouts were killed near Little Sioux, IA. The state ended the summer with heavy rains and more flooding in July, and then a record-setting dry spell for the month of August. The warmth of summer and fall would be the only headlines for the next couple of months, with a very late fall freeze. This warmth continued into the early part of November with temperatures continuing in the 70s and even an 80 degree reading. We finally got back to the cold air that we started out the year with in the latter half of November and this has continued for the most part through the end of the year. December has also brought headlines with the continued round of snow storms, with blizzard and near-blizzard conditions and snowfall amounts greater than 20 inches to lead this month as the 4th snowiest December in Iowa history.

For a complete review of 2008 view the Des Moines NWS document here: DMX NWS Year in Review

Another read for those interested in this years' tornadoes across the state will be the table-listing of all tornadoes. It includes the city, county, specific location and time of each tornado; it will also show the maximum length and width of each tornado along with any injuries and deaths that unfortunately were to occur with the tornado. To view this document, head to the link: 2008 Iowa Tornadoes

Thanks for making this a successful year of the blog, with several thousands of readers and with the comments and views that I'm sure to keep going. Hope you had a great 2008, and here's to looking forward to a even better 2009!

Melting Ice

The past couple of days left parts of the state under a few tenths of an inch of ice, while other parts saw plenty of melting snow due to the rainfall that was occurring. This rapid melting and additional rainfall has prompted a few flood warnings over the southeast quarter of the state. Additional melting is likely to occur over the next few days as well as temperatures continue to be well above normal through Tuesday before our next storm system begins to work into the state. For the quick recap on the past few days weather, a map below shows the ice accumulations that have occurred on Dec. 26/27:

For the next few days it looks like we'll stay dry and warm with southerly winds and sunny skies. Through Tuesday you can expect highs to range from the lower 30s across northern Iowa to the lower 40s across the southern third of the state. The lows to go along with these warmer temperatures during the day will also be well above normal, with the teens to mid 20s expected Sunday night. Monday night will be even warmer with lows near 20 across the north and near 30 on the southern border of the state. Beyond these warmer temperatures we'll see another storm system move in and give us a chance of snow on Tuesday night for northern Iowa; expanding to cover more of the state for Wednesday and later. It looks like we'll end the year without another major storm system, time to prepare for 2009!

Mixed Precipitation...

The Holidays have been busy, thus I'm sure with everyone traveling the road conditions have been important to many. There hasn't been too many problems thus far, with mainly some snow and blowing snow to contend with on the roads. Yesterday was quite warm with a warm front moving north over the state allowing temperatures to reach well into the 30s and 40s even with snow cover. These warmer temperatures are now on their way back down with a cold front passing through the state. This cold front and associated low(s) are responsible for areas of sleet/snow and freezing rain over parts of the state this morning.

A Winter Weather Advisory has been issued for many areas along and east of I-35 for this mixed bag of precipitation that should continue through this afternoon and into the overnight hours. Areas along I-35 should see light accumulations of both sleet and freezing rain during the day, with snow beginning in the evening and into the early overnight with accumulations of 1-3 inches of snow. Further east the situation becomes a bit messier with rain expected through much of the day, with isolated thunderstorms even included in the forecast. Rainfall totals of a quarter to half-inch are possible, with an eventual change to sleet/snow being possible during the evening and into the overnight. Travel conditions are likely to be hazardous over the eastern half of the state beginning this evening and continuing through the overnight hours with the mixed precipitation.

Even More Snow!!

While the first brush of snowfall has made its' way over much of the state during the overnight hours it will keep a few flurries or snow showers around in the central/eastern parts of the state early today. A dusting to a few inches may be expected from central to eastern Iowa, the eastern third of the state has been put under a Winter Weather Advisory for their chances of seeing an additional 1-3 inches of snowfall today, leaving their storm totals from 2-5 inches. This additional snowfall has created some troublesome areas of travel as roadways are being reported as mostly to completely covered this morning.

Beyond today's snowfall, the next event to come across the state is expected on Wednesday as a low pressure system begins to form over the Midwest and track northeast. This low will move east of the state of Iowa, but it will likely put areas of eastern Iowa in a favorable location for receiving potentially significant snowfall amounts. It is for this reason that areas of eastern Iowa (approximately the eastern third) have been put under a Winter Storm Watch for Wednesday. While much of the state may see a few flurries or light snow, areas east of a Nebraska City, NE to Des Moines to Waterloo to LaCrosse, WI line will likely see greater than 3 inches of additional snow. Some areas, mainly east-central Iowa, may have the potential for 6 inches or more of snow through Wednesday. This snowfall combined with an increase in winds will create blowing and drifting snow, and of course hazardous driving conditions on Christmas Eve. Later updates will refine the snowfall totals and locations for this Christmas Eve snowfall...

The latter half of the week will be full of interesting weather to go along with those interesting family times. A potentially strong storm system to the west of the state will lift warm air into and through Iowa during the day on Thursday and Friday. This warm air will allow even surface temperatures in the upper 20s and lower to mid 30s despite the snowfall. While this will hopefully create a crust on the current snowfall to hamper any additional blowing snow, it may create problems of its' own with any precipitation that falls. Forecasts have a wintery mix, to even rain in the forecast across the state on Thursday afternoon through Saturday. As you may be thinking, ground temperatures will certainly not get above freezing with the considerable snow cover, thus leaving any liquid precip as freezing upon contact with surfaces. Be prepared to leave early or travel in some hazardous conditions if this comes to be for the latter half of the week. Luckily at this time it does not appear to be significant or widespread, but something to keep an eye on for holiday travel.

I had a question on the previous blog entry about more of a long range forecast, and wish to at least give recognition to it here. With all that has been going on in the short term, I haven't taken a long look at the January forecasts, etc. Weather models in the long range will change quite often, thus there is no good way to indicate anything more than trends. Current Climate Prediction Center forecasts do have Iowa in a probability area of seeing above normal temperatures in January. Above normal temperatures in January won't necessarily be above freezing, rather temperatures in the teens and 20s on average instead of some single digits and lower teens.

A little more snow...

Another storm system will clip the state tonight and continue to produce some light snowfall through Tuesday night. While snowfall amounts are not expected to be too high, just below advisory criteria, the snow combined with already full ditches may produce some troubled driving conditions over parts of northern Iowa. Temperatures should become a little warmer with the snowfall, and continue to be warmer than the past couple of days through Wednesday.

Total snowfall amounts through the next 36 hours should range between only a trace for areas southwest of a Sioux City to Ottumwa line; with 2-4 inches possible for areas northeast of a Spirit Lake to Waterloo to near Davenport line. The area in between should see 1-2 inches of snowfall... Winds are expected to be breezing, at 10-20 mph which may give way to some blowing snow, especially in those areas where the ditches, etc. are already full.

In a previous post I included an image of snowfall depth across the state, and with the last snowfall there is now an updated snow-depth map that is attached below:

Winter Storm (Dec. 20) Update #2

Light to moderate snowfall combined with strong northwesterly winds have allowed travel conditions across the state to deteriorate throughout the day. Most of north-central and northeast Iowa have been advised to not travel due to the road conditions. These strong winds will continue to create hazardous travel conditions across the northern half of the state through early Sunday.

Beyond the blowing snow and windy conditions, these will combine with temperatures near or below freezing throughout the next 36 hours to create dangerous wind chill value. Much of the state will see wind chills below -20 during the day tomorrow, and even below -30 during the evening and overnight hours tomorrow and Monday night as well. Be sure to keep bundled with the very cold and windy conditions through Monday night...

The image below is the latest snow depth across the state of Iowa:

Winter Storm (Dec. 20) Update #1

The Blizzard Warning has been expanded to include areas along and north of Highway 20, and areas along and west of I-35. A Winter Storm Warning has been issued for northeast Iowa where snowfall amounts and winds will still create hazardous conditions, but won't quite reach blizzard criteria. Snowfall has continued to fall this morning across the state, with 2-4 inches expected across the northern third of the state. The central third of the state should see 1-3 inches, and the remainder of the state may see an inch or so. Although travel conditions aren't too bad at the moment with only snowfall, as a cold front sweeps over the state the winds will increase significantly this afternoon and continue into Sunday. These northwest winds will likely be sustained at 20-35 mph, with gusts up to 40 mph. The combination of fresh snowfall and these winds will create blizzard or near-blizzard conditions across the northern third of the state of Iowa as well as areas of Minnesota and South Dakota. These blizzard conditions are likely to continue into Sunday morning and early afternoon, making traveling very hazardous or not impossible over some areas.

I did have one comment on the previous post asking about travel conditions, making the trip from near Rochester, MN to Des Moines, IA. While I can't say if they will be closing down I-90 or I-35; it will be a very hazardous trip to make anytime during the day today/tomorrow. It may have been best to make the trip early this morning, or else you can wait until later on Sunday and hopefully the winds may subside a little early. Updates may be posted as blizzard conditions begin and continue through today and tomorrow...

Winter Storm (Dec. 20)

The third winter storm of the week is headed towards the state and will begin early tomorrow and continue into Sunday. Areas along and northern of highway 30 are most likely to be effected by this storm, and this is where there are currently Winter Storm Watches issued for north-central and northeast Iowa. Parts of northwest Iowa have been put under a Winter Weather Advisory for tomorrow morning, and then a Blizzard Warnings for the afternoon into Sunday morning. The portions of the state that are currently not under an advisory/warning are likely to be put under one later this evening/tonight. A band of 1-3 inches of snow is possible between highway 30 and highway 20; the northern third of the state is likely to see 2-4 inches with isolated higher amounts.

The bigger story of this winter storm will not be the snowfall amounts like the last one; rather the high winds that are to pick up after the snow falls. Once a cold front slides through the state during the afternoon hours tomorrow, expect winds to increase out of the northwest at 15-25 mph sustained with gusts near 35 mph. These winds will create heavy blowing and drifting snow, and dangerous wind chill values throughout northern Iowa.

The next storm update is possible late tonight once any updated advisories/warnings have been issued...

Winter Storm (Dec. 18) Recap

A dangerous winter storm created havoc for much of the state of Iowa, and surrounding locations. Snowfall was prominent throughout the northern half of the state where 5 inches or greater was seen. The heaviest snowfall was in parts of northwest and northeast Iowa where reports of greater than 8 inches were received. Luckily this snow was very light and fluffy, and with little in the way of wind it was not a problem to get off of the roads. The other concern was the ice and sleet that occurred over much of central and southern Iowa, the heaviest amounts seemed to be in localized locations across southern Iowa. Images of the snow accumulations and ice accumulations via the NWS Des Moines are posted below.

Ice Accumulations

Snow Accumulations

Winter Storm (Dec. 18) Update #4

The winter storm has arrived! Widespread reports across the southern half of the state of sleet and freezing rain, with some accumulation and icing already occurring. Some areas of southeast Nebraska have already reported a half inch of sleet, and other reports of an eighth of an inch of ice accumulation. These heavier reports have been co-located with reports of thunder and lightning that were quite frequent. These heavier amounts have just moved into southwest Iowa as well, with the latest report coming in from Council Bluffs, IA with nearly a half inch of ice accumulation; power lines are already sagging there.

You can view the latest radar from the Iowa Chaser homepage, as you see the precip overspread the entire state!

Watch your local news and check your local National Weather Service homepages for the latest updates and accumulation statements. Undoubtedly a very dangerous winter storm, be sure to also watch the road conditions across Iowa via iowaroadconditions.org where you can also watch the conditions rapidly deteriorate.

Winter Storm (Dec. 18) Update #3

Our potent winter storm is taking its' time to move through the plains, the low pressure system is currently over eastern Colorado and is expected to make its' way off of the Rockies this evening. Rapid pressure falls have been occurring over western Kansas, indicating that the low should move to the east/southeast over the next few hours. Once off the Rockies this low will rapidly move eastward over Kansas and through northern Missouri overnight, leading to heavy precipitation over parts of Iowa. The latest weather models have moved the the system just slightly north, moving the axis of heaviest snow/sleet with it. Once again both of the main weather models (NAM & GFS) are in remarkably good agreement with the movement of this system as well as precip amounts.

The heaviest freezing rain should still be south of I-80, and especially over south-central and southeast Iowa where nearly a half-inch is likely. Other areas south of I-80 should still see a quarter of an inch or more of ice. Sleet is also likely to occur over much of central Iowa between the I-80 and highway 30 corridors; total amounts between a half-inch and an inch are likely. Heavy snow throughout the night seems likely over the northern half of the state, with embedded thundersnow also possible. An axis from near Sioux City through Algona, and eastward toward LaCrosse, WI and points north/south within a few counties are likely to have the heaviest amounts of 6-10 inches. Other areas are still likely to see 4-8 inches...

More brief updates late tonight or early tomorrow are likely with reports of accumulations...

Winter Storm (Dec. 18) Update #2

The National Weather Service offices that cover the state of Iowa were busy last night, issuing several different winter weather advisories/warnings. A quick overview of these warnings: A Winter Weather Advisory is in effect for a few of the far western Iowa counties, a Winter Storm Warning is in effect for areas north of I-80 throughout much of central and eastern Iowa; and finally a Ice Storm Warning is in effect for much of the state that is south of I-80. These advisories and warnings go into effect this afternoon and will continue into Friday morning while precipitation falls throughout this period.

The latest models are in very good agreement for this winter storm with both positioning and QPF amounts, along with precipitation type. The heaviest band of snowfall is expected to fall from a line just south of Sioux City, northeastward to near Webster City, and then just south of LaCrosse, WI. Areas along and north/south of this line are likely to see greater than 6 inches of snow, with isolated amounts near one foot. These heavier snow amounts may likely occur within areas of embedded thunder, in fact, several areas in the southern half of the state may see embedded thundershowers with this system. These thunderstorms will have the potential to put down several inches of snow, or significant amounts of sleet or freezing rain within a short period of time.

This system has the potential to be extremely hazardous, producing over a half inch of freezing rain for the southern third of the state; significant sleet and freezing rain mixtures; and very heavy snowfall amounts. Des Moines NWS once again has a very good graphic depiction of the events likely to occur this afternoon and through the overnight hours. Thanks to a reader that posted a comment in the previous update, indicating that freezing drizzle is already beginning over parts of the state.

Winter Storm (Dec. 18) Update #1

Winter Storm Watches still are to remain in effect until later tonight where they will likely be changed over to some type of winter storm warning, whether it be for snow, or sleet/freezing rain. This mornings computer models came into a little better agreement on the placement of significant freezing rain and sleet. However, the overall location of the heaviest precipitation was still somewhat varied in mainly the east/west location. For a quick overview, models are still expecting a low pressure system to develop off of the lee of the Rockies on Thursday and quickly move into the central plains by Thursday night. The low track is expected to be through northern Missouri and into central Illinois, thus putting Iowa into the favorable area for continued precipitation. Rapid moisture return ahead of the system (up to 3 times the climatological average), along with warmer temperatures will allow for significant QPF amounts. This system is fast-moving, thus precipitation may begin Thursday afternoon over the state and may exit the state completely by Noon on Friday. For a graphical depiction of what is expected, please view the graphic below:

Yes, the image is hard to read... It has to be to put in all of the different precipitation types and amounts that are expected with this storm. Essentially the blue circle represents areas where more than 4 inches of snow is possible; the yellow represents up to an inch or more of sleet; and the red indicates areas where more than a tenth of an inch of freezing rain is possible. Enjoy this weather!

Winter Storm (Dec. 18)

The entire state of Iowa is now under a Winter Storm Watch for Thursday and Thursday night, with significant accumulations of snow, ice, and sleet possible dependent on your location in the state. A storm system is expected to develop during the afternoon hours on Thursday, with a low pressure center likely to track through northern Missouri and into central Illinois. This will put the state of Iowa in a favorable location for continued precipitation during the afternoon hours on Thursday and continuing into early Friday. With moisture expected to be sufficient, over a half-inch of precipitation is likely throughout the state with some higher amounts. This precipitation may fall as freezing rain, sleet, and snow creating very hazardous driving conditions.

Current forecasts would indicate that the southern half of the state may see greater than a tenth of an inch of freezing rain, followed by sleet and a few inches of snow. The northern half of the state may see some freezing rain and sleet, but a majority of precipitation should fall as snow; leading to more than 6 inches of snowfall for most of the area. These winter storms are especially hard to forecast for, so be prepared for all modes of winter weather including significant icing, sleet, and snowfall...

An afternoon update will likely be posted with any forecast revisions...

Winter Storm (Dec. 16) Update #3

The snow has subsided over most of the state, with only a few flurries or light snow showers over eastern Iowa. Total snowfall amounts were generally 3-4 inches over the state, with a few locations seeing a little more or little less. The highest amount through the Des Moines NWS office was near 5 inches in Jefferson. Here in Ames we saw just about 4 inches of the fluffy white stuff fall throughout the day...

Some hazardous travel conditions occurred when the roadways were completely covered, with a few accidents being reported throughout the state. Just a short update here, I've attached the general snowfall image from the Des Moines NWS to give you an idea of how the snowfall accumulated over the state.

Look for an update tomorrow morning that will give you the forecast for the next winter storm that will move across the state on Thursday. A Winter Storm Watch has already been issued for much of eastern and southern Iowa where significant ice/sleet/snow is possible. For a quick look at what is possible, the latest weather story from Des Moines is a sight to see:

Winter Storm (Dec. 16) Update #2

Light to moderate snow has continued across the state for much of the morning hours, accumulating snow at a slow but steady pace. No official snow amounts besides the NWS in Johnston (1/2 inch) have came out, although I can say Ames looks to have nearly 2 inches of snow on the ground at this time. The radar has been updating on the Iowa Chaser homepage for most of the morning, and as you can currently see the heaviest of the snow looks to be over the western third of the state. This heavier band of snow should move through central Iowa early this afternoon and over eastern Iowa during the late afternoon hours. Total snowfall accumulations over the southern two-thirds of the state should be in the 3-5 inch range, while extreme northern Iowa should still have at least 2 inches of fresh snow on the ground. Expect the snowfall to end over western Iowa this afternoon, over central Iowa this evening, and over eastern Iowa during the early overnight hours.

Travel conditions are not too bad, they are partly to mostly covered with snow dependent upon the last time the plows have went over the area. Do expect some slower travel beings the snow can be slick at times, but overall this system is just a nice snow-maker.

Winter Storm (Dec. 16) Update #1

A winter weather advisory has been issued for all but the extreme portions of northwest Iowa beginning tomorrow morning and continuing into Tuesday night. Areas under this advisory may see 2-6 inches of snowfall with some isolated higher amounts possible. The heaviest snowfall is still likely to be over the southern two-thirds of the state, with the northern third likely to only see 2-4 inches. This snowfall will be moderate to heavy at times as it moves through the state tomorrow, so expect some hazardous travel conditions.

Winds are expected to be lighter, thus blowing and drifting snow is not a large concern. Temperatures are still likely to remain well below freezing, leading to the significant snow amounts across the state. More updates on the winter storm will be posted tomorrow afternoon as the snow falls.

Winter Storm (Dec. 16)

Our next winter storm will make its' way into the state by tomorrow morning, and with the frigid air in place it will undoubtedly be an all snow event for the state. As our storm system that affected us yesterday continues to move east, an area of high pressure will setup over the state today and tonight keeping the temperatures well below normal. We'll then see a wave of energy come through Tuesday afternoon, this is what will be responsible for the snowfall across the state of Iowa and surroundings. Although the system as a whole does not look potent, the combination of the shortwave and temperatures will allow for moderate to heavy snowfall to occur across the state.

The computer models have been consistent in bringing this snowfall over the state throughout the day on Tuesday, thus there are no real concerns of this event not happening over Iowa. The band of heaviest snowfall has been consistently painted by a consensus of the models over the southern third of the state. Northern Iowa won't miss out though, still seeing several inches of snow throughout the state. The snowfall will be heaviest in the morning hours over western Iowa, the afternoon hours in central Iowa, and then during the evening hours over eastern Iowa. Although winds are not expected to be as high, thus limiting the blowing snow; travel conditions are still likely to be hazardous due to the snow and reduced visibilities.

With QPF expected in the .2 to .5 range across the state, and with snow:water ratios ranging from 12:1 to 20:1 it will not take much to see snowfall rates greater than an inch per hour. This has led me to this crude map of potential snowfall amounts across the state for tomorrow. Enjoy the snow! An update will likely be issued tonight upon the NWS issuing advisories/warnings for this storm system.

Winter Weather (Dec. 14-15)

Plenty of updates today with this strong system moving through the plains states, and directly over the state of Iowa. As the low pressure system moves through Wisconsin tonight, expect continued northwesterly winds at 20-30 mph with higher gusts. With frigid temperatures and these high winds, the concern over the entire state will be wind chill values in the -10 to -30 degree range. These values have prompted nearly the entire state to be put under a Wind Chill Advisory. Some bands of snow are possible over areas of northwest Iowa, where less than an inch is expected. However, with the strong winds a Winter Weather Advisory has been issued for some areas in northwest Iowa due to the strong blowing snow. In the southeast, a heavier band of snow is likely to take place tonight and allow anywhere from 1-2 inches of snow and sleet to fall. This combined with the strong winds will also allow for blowing and drifting snow, leading to the issuance of Winter Weather Advisories and Winter Storm Warnings.

So for tonight, expect continued strong winds and bitterly temperatures, along with some snow in the northwest and southeast. Hazardous travel conditions are likely throughout the state, and bitterly cold temperatures and wind chills are definite.

Expect the temperatures to slowly rise tomorrow, and the winds to slowly decrease as well to allow the wind chill values to make it above -10 and thus void any wind chill advisories. We'll only see a one day break from the snow though, as Tuesday looks to have another storm system dropping upwards of 6" of snow somewhere in Iowa!

Amazing Cold Front

The cold front that has been plunging southward today continues to do so through nearly the entire plains states. This front not only has such deep cold air behind it that is creating below zero readings from Montana through the Dakotas and Minnesota, but is so strong that is has over 30 degree drops in temperature along it without the aid of any precipitation! Temperatures are in the teens from northern Minnesota into the panhandle of Oklahoma, with temperatures in the 50s as far north as Illinois ahead of the cold front. The low pressure system responsible for such a strong front can clearly be seen through the image below, just temperature gradients alone should give it away let along the strong winds that wrap up nicely around it.

The image below should tell it all, with the temperatures shown in the red text, and temperatures also color-contoured for emphasis. Winds shown through the wind barbs as well to indicate the cold air rushing in behind as the front passes.

Welcome Back Winter...

Winter tried to take a break from the state, with temperatures rising well above freezing in some areas and the sun shining brightly. It didn't last too long though as a strong cold front and low pressure system have moved into the state this morning and allowed temperatures to free-fall with winds increasing 20-35 mph. The combination of falling temperatures and continued high winds will allow wind chill values in the -20s and -30s tonight across parts of northern Iowa. Some snowfall is also expected across the state this afternoon and overnight as the cold front and low pressure system move through. The heaviest amounts are likely over southeast Iowa where 1-2 inches of snow is possible during the overnight hours. Beyond today, expect the cold conditions to continue through Wednesday this week...

Lows tonight ranging from -10 to 10 degrees from the northwest corner to the southeast corner. As mentioned previously, with strong northwest winds the wind chill values will be well below zero across the entire state. Highs on Monday will range from the single digits to the teens across the state, with lows falling into the teens below zero and single digits at best. A slight warm-up on Tuesday with highs near 10 to near 20 from northwest to southeast. Tuesday night lows will range from the single digits above and below zero to a few temperatures just above 10 degrees in the southeast. Teens to lower 20s expected on Wednesday, with lows overnight finally ranging in the single digits above zero for the entire state.

I'll leave today's post with an image that I took today just north of Pocahontas, Iowa where a northbound semi lost control due to high winds and somewhat slick conditions and managed itself into the southbound ditch.

Dec. 8-9 Ice/Snow Accumulations

Although blowing snow continues to create some problems, the snow is exiting the state and we will just be left with the wind and cold to deal with. Snow accumulations were not as high as expected for most of the state yesterday into today, this was mainly due to some slightly warmer air being present just above the surface. This warmer air allowed the snow that was falling to melt before reaching the surface, and then freeze upon contact creating the freezing rain. Freezing rain accumulations ranged from a tenth across much of the state to over three-tenths in parts of northeast Iowa. Each tenth of an inch of freezing rain could have easily contributed to more than an inch of snow, adding to the accumulations that those areas received later on during the early morning hours after the freezing rain had turned into snow.

The snow accumulations weren't light everywhere, with much of northeast Iowa receiving 5-9 inches of snowfall on top of the couple tenths of ice accrual. Areas that only saw a couple inches of snow still didn't make it without trouble due to strong winds blowing the snow around on top of their minor ice accumulations. Maps of the snow/ice accumulations are being added below when available:

Beyond today's cold and windy weather we can look for only partly cloudy skies the rest of the week with temperatures in the 20s to mid 30s from northeast to southwest across the state. Lows overnight will be in the single digits and teens tonight, to the teens and low 20s for the rest of the week. We look to only have a small chance at some flurries a few nights, otherwise looking towards early next week for our next round of winter precipitation.

Winter Storm (Dec. 8-9) Update #2

Precipitation has been falling off and on throughout the entire state this afternoon and into this evening. While the northern third of the state has seen this precip turn over to snow, other areas of central Iowa are seeing freezing rain, while the southern third is hanging onto rain. This type of precipitation should continue through the early nighttime hours, with the northern third of the state continuing to see snowfall and the other portions seeing a mix of freezing rain and rain. By the late nighttime hours, the snow should begin to fall over the central third of the state while the southeast quarter of the state stays rainfall. Waking up on Tuesday will likely be quite the mess with ice accumulations in some areas, heavy snow in others, an majority of the state in a simple mess of winter weather.

The heaviest snowfall accumulations are expected to occur over north-central and northeast Iowa where winter storm warnings have been issued with 4-8 inches of snowfall possible. Other areas under a winter weather advisory may see snowfall accumulations of 2-6 inches, or some ice accumulations along with moderate snow. Only the southeast quarter of the state will be able to remain under a couple inches of snow, with little in the way of ice accumulation as well. Other areas of extreme weather Iowa will be far enough away from the low to only see a couple inches of snowfall.

Keep up with the latest road conditions and the latest radar from the Iowa Chaser Homepage.

Winter Storm (Dec. 8-9) Update #1

Well I know the previous post mentioned that a better idea of snow accumulations would be presented in this update tonight, but honestly there can't be that much accuracy stated at even this point. Tonight's model runs at first glance have continued their trend of a north and west movement of the heaviest snow, likely due to the more progressive nature of the system. However, this does not seem to hamper any of the current NWS statements on the winter storm watches currently in effect and it certainly doesn't mean that the new solution will verify either. I am however not going to be able to provide a solid map for your visual reference on how much snow areas are likely to receive.

Precipitation is likely to begin by the evening hours tomorrow, with a few scattered showers during the afternoon hours previous. With the strength of warm-air that is likely to push into the state, it does appear that rain may be the beginning form of precip for much of the southern half if not greater portion of the state. Current surface analysis indicates this warm front is already in the process of taking shape over the southern third of the state. This will provide the good possibility of freezing rain for much of the state on Monday afternoon and into the evening hours. As we head into the heavier precip on Monday night, expect western and northern Iowa to be mainly snow, central Iowa to be mainly snow with the transition a little later in the night, and expect southeast Iowa to be mainly rain; leaving parts of south-central, central, and east-central Iowa with the possibility of continuing freezing rain. All in all, with the amount of precipitation expected with this storm system, a good winter storm is nearly a guarentee, it is just the location that is tricky at the moment.

Latest forecast discussions tend to agree with this detail, with the heaviest band of snowfall possibly falling anywhere between the I-90 corridor in southern Minnesota and northern Iowa, to south-central to east-central Iowa. As mentioned by Des Moines NWS, central Iowa does appear to be in the most likely area for this heaviest band of snowfall to setup during the overnight hours on Monday. Widespread 4-6 inches of snow is likely, with isolated amounts nearing 8 inches. Areas just to the north/south of this heavier band should still see 2-4 inches, with only extreme southeast Iowa perhaps making it out with only an inch or two as they receive more rainfall than snow...

As I type, I figured I might as well make up a map... So it is posted below, notice the area encircled in yellow I believe has the best chance of 4-8 inches of snowfall; while areas outside of the yellow both north and south will be looking at 2-4 inches. The area encircled within blue will see freezing rain with some accumulations possible, while south of the green line you can expect mainly rain with only minor snowfall accumulations.

Winter Storm (Dec. 8-9)

The first true winter storm may end up slicing through the state of Iowa on Monday night and through Tuesday. Winter Storm Watches have been issued for several counties through both central and eastern Iowa where snowfall accumulations of 4-6 inches are currently forecasted. Other areas of the state will still likely see snowfall, where 2-4 inches is likely across western Iowa. The southeast part of the state looks to have a mix of precipitation, with some freezing rain/sleet possible before snow takes over and accumulates. Still a sensitive forecast with models being varying in location of the band of greatest snowfall, but it does seem to have a consensus in that it will be across some portion of the state of Iowa.

A few light snow showers may be across the state on Monday afternoon, but little accumulation is expected through the evening hours. By Monday night precipitation should expand across the entire state as a low pressure system in the central plains begins to wrap moisture around itself. The precip will be mainly snow for all but the southern third of the state where a rain/snow mix is possible through the nighttime hours. By Tuesday the cold air has pushed down through most of the state to allow for mainly snow. As the low moves off to the east, expect the snow to taper off in the northwest by Tuesday afternoon, and over the rest of the state by Wednesday morning. Although the snow is expected to stop, the strong winds of 20-30 mph will keep the snow blowing throughout the state to keep road conditions quite hazardous.

An update later tonight will provide a little more insight on where the strongest band of snowfall accumulation may setup, and exactly how much snow that band could create.

Dec. 3 Snow Accumulations

Snow amounts today weren't as heavy as anticipated, with the line of snow moving through quicker and being narrower than forecasts. Accumulations still caused plenty of travel hazards, as over a dozen accidents just around the Des Moines metro area occurred this morning, including a 9 vehicle accident just north of Des Moines. Storm total accumulations:

Ottumwa - 3.5"
Oskalooska - 3.0"
Rathbun - 2.0"
Knoxville - 2.0"
Des Moines - 1.6"
Lamoni - 1.0"
Ringsted - 1.0"
Waterloo - 0.8"
Mason City - 0.7"
Iowa Falls - 0.5"
Algona - 0.5"

Skies are beginning to clear, with just a few flurries being possible across northwest Iowa tonight with a weak disturbance. Temperatures tonight will be chilly, with northwest winds beginning to die down a bit they will be able to drop just a little further into the single digits over northeast Iowa and into the teens across the rest of the state. High temperatures on Thursday will be in the 20s throughout, with a few flurries still possible over mainly northwest Iowa. Thursday night lows will be even colder, with single digits over all but southwest Iowa! Friday's highs will warm up just ahead of our next storm system, ranging from the lower 20s to mid 30s from northeast to southwest. Friday night will see lows in the 20s for the most part, with mostly cloudy skies keeping them up compared to previous nights. Friday night snowfall should yield only a dusting to at most an inch, as moisture is fairly scarce at this point.

Into the weekend expect to see temperatures hovering in the 20s to near freezing, with lows in the single digits and teens on Saturday and then into the teens and 20s on Sunday night. This will lead into our next storm system entering the state on Sunday night and lasting into Monday. Snowfall is likely, although some mentions of sleet have also been thrown out in forecast discussions today. More details on this system in later updates...

For now, I'll leave this update tonight with a nice picture from earlier this summer of a Goldfinch that was taking a rest on a Lilac bush. A friendly reminder that the warmth is only 5 months away!!

More Snow!

A cold front has made its' way into and through northwest Iowa this evening, and will continue to move southeastward through the overnight hours. Behind this cold front will be another shot of cold air, and along with it a chance at a few hours of moderate to heavy snowfall. A large portion of the eastern two-thirds of the state is under a Winter Weather Advisory with 2-5 inches of snow being possible in those areas. Other parts of western Iowa will still see the snowfall, but their amounts should be less than 3 inches. For a graphical reference to the snowfall amounts, check out the latest Weather Story from Des Moines NWS.

Expect the snowfall to being just after midnight for northwest Iowa, with the heaviest amounts coming between 3 AM and 6 AM. This band of heavier snow should then work through a majority of central Iowa by Noon, and then into eastern Iowa during the afternoon hours. The snow may be heavy at times, and with northwest winds 15-25 mph expect some blowing snow to hamper driving conditions. Visibilities will easily drop below a mile, and with some slick conditions present after today's slight melting don't be surprised to see some hazardous travel.

Keep up on the latest road conditions across Iowa by using the Iowa Environmental Mesonet Roads page.

Look for the next update tomorrow afternoon with information on snow totals thus far and an updated temperature forecast as the cold air settles in!

Nov. 29 - 30 Snowfall Totals

Light to moderate snowfall continued for several hours from Saturday night through Sunday, leading to snowfall totals of over 6 inches in some portions of Iowa. Although much of western Iowa missed out on the snowfall, a band of heavier totals exists through central Iowa and into northeast Iowa. The image below is taken from the Iowa Environmental Mesonet and is the cooperative observers across the state and what they reported for total snow on the ground on Monday morning.

The next chance of snow for the state comes on Tuesday night into Wednesday, where a quick moving system will bring the potential for at least another dusty of snowfall across much of the state. More details on the potential for snow accumulations in tomorrows update!!

Snow Continuing...

Snowfall began across the state yesterday evening, and has continued through the nighttime hours and into the morning hours today. The snowfall should continue over much of the state this morning, moving slowly eastward and out of at least the western half of Iowa by this evening. Overnight tonight the snow should continue over eastern Iowa, before tapering off in the early morning hours on Monday. Total accumulations between 2-4 inches are likely in an area that is currently in a Winter Weather Advisory. This advisory encompasses an area roughly defined as areas east of I-35 and south of Highway 20. Just north and west of the advisory should still see an inch or so of snowfall accumulations through today as well, with only the extreme western portions of the state seeing a dusting.

Total snowfall amounts through the 7 AM hour as provided by CoCoRaHS (locations approximate):

Cedar Falls - 3.5"
Pella - 2.5"
Nevada - 2.3"
Grimes - 2.2"
Osceola - 2.2"
Ankeny - 2.2"
Creston - 2.0"
Cedar Rapids - 1.7"
Webster City - 1.5"
Bettendorf - 1.0"
Davenport - 1.0"
Britt - 0.5"
Manning - 0.4"
Ruthven - 0.2"

A bit of snow...

Some light rain and snow showers are moving across the state this morning and should continue to do so this afternoon. Overnight tonight we should see it turn over to an all snow event with some accumulations possible, especially over eastern Iowa. These scattered showers will taper off on Sunday, but not before another dusting or more can accumulate on the cold surfaces. As mentioned, accumulations are likely over the state mainly tonight, with only a dusting to a half inch of most of the western half of the state. Once along and east of I-35 you can expect an inch to nearly 2 inches of accumulation into Sunday morning. You can check out the latest Weather Story from the Des Moines NWS to see a graphical depiction of the snowfall expectations.

Temperatures this Saturday afternoon should be in the mid 30s to lower 40s, with cloud cover and isolated rain/snow showers possible. Lows tonight in the mid 20s to near 30 from northwest to southeast across the state. Snow showers possible in western Iowa with light accumulation; snow likely across central and eastern Iowa with accumulations of 1-2 inches. Highs on Sunday in the mid 30s across the entire state, with flurries possible across western and central Iowa; snow continuing over the eastern third of the state with up to an inch of additional accumulation. Sunday night lows in the upper teens to lower 20s from north to south, snow flurries ending across the eastern third of the state.

Highs should begin to rebound for Monday/Tuesday before the next system clips the state and brings a small chance of precipitation Tuesday night into Wednesday. This system will also bring down the cooler air once again over the state. Details on the first week of December in the next update!

Great Thanksgiving Forecast

This week couldn't turn out too much better for those that are getting their holiday break to enjoy some good food, some family/friends, and I suppose some good shopping! The temperatures should be near/above normal for most of the state, and even better is that we look to stay mainly dry into the weekend! Temperatures today should range from the upper 30s to upper 40s from east to west, with lows tonight in the lower to mid 20s across the state.

The clear skies continue on Wednesday with temperatures in the 40s throughout the state of Iowa. Outside of Iowa, the rest of the plains states should also see continuous sun with temperatures ranging from the mid 30s across northern Minnesota and northern Wisconsin, into the 40s across Illinios, southern Minnesota, southern Wisconsin, and through eastern South Dakota. The warm spot on the plains will be out west, with western South Dakota and Nebraska seeing temperatures in the 50s. Overnight lows on Wednesday in the 20s throughout Iowa and nearly all of the plains states.

Thanksgiving Day leaves high temperatures in the 40s throughout Iowa, with lower 30s to upper 40s from north to south across the entire northern plains. A few clouds may move into some areas of the plains and Iowa, with a few flurries not out of the question mainly over Minnesota and Wisconsin. Thursday night continues a few flurries over MN/WI, with temperatures in the upper teens to upper 20s from north to south across the northern plains.

Enjoy the Thanksgiving Day forecast... More details on our next potential snow for Iowa in the late week update!

Book Pre-Release: Natural Scenes

As I mentioned within a previous post, a book featuring images that I've taken over the course of the last several years is being released for sale. I've got a good amount completed, and thus have issued a pre-release sale for the book as you can find on the newly designed and opened ChaserSupply. You can read more information on the sale page at ChaserSupply, but if you enjoy any of the images that have been posted on the blog here you are sure to love the images in this book!

While the book is a little on the pricey side, I have to admit that, it is a solid book that is made to be used on your coffee table for all to enjoy. The hardcover is just that, a hard cover with full color images on the front/back that is sure to get you and your guests attention. If you would really like to purchase the book, send me an email (photos@iowachaser.com) with your request and will send you some information on how you can receive a discount by reading my blog!

Once again, my premier release of the book Natural Scenes to be shipped out on December 10, 2008 is now available for pre-orders!

Downright Cold!!

Earlier this week we saw some temperatures in the lower teens over a large portion of the state. We did manage to bounce back with some warm temperatures early on Wednesday, but have since dropped back down into the chilly conditions. Tonight we are setting ourselves up for an even colder night than we saw earlier this week. Colder and drier air is moving in, allowing the clouds that were present early today to evaporate away. With clearing skies, and the combination of winds decreasing to below 5 mph we set ourselves up for a strong radiative cooling night. Radiative cooling is essentially the conditions for the ground to lose the heat that it has stored up from the daytime sun. Beings much of the northern plains will be under these conditions, expect some very cold temperatures when we get up tomorrow!

Lows temperatures tonight across Iowa will likely range from the single digits to only the lower teens. Northwest Iowa is likely to be the coldest, with values nearing the 5 degree mark! High temperatures for Friday will not rebound significantly, with upper 20s to mid 30s from northeast to southwest. A quick moving system will move a band of snow showers into the state for Friday evening/night. The best chance of accumulating snow exists from Sioux Falls, SD through Fort Dodge and nearing the Iowa City area. Low temperatures will likely be in the upper teens to lower 20s across the state. A few lingering snow flurries are possible in eastern Iowa on Saturday, with high temperatures in the upper 30s to upper 40s from northeast to southwest. Mid 20s to near 30 for lows both Saturday and Sunday night across the state. High temperatures on Sunday in the 40s throughout Iowa...

Thanksgiving vacation is finally upon us! Hopefully will get a little more relaxing time and will be able to give some good updates as well still look towards that first big snowfall and winter storm!

A Few Updates...

Been a busy last couple of weeks on my end, which may be why you aren't seeing as in-depth forecasts and as frequent forecasts as usual. Currently working on finishing a thesis project entitled "Synoptic Environments Associated with Significant Tornadoes in the Contiguous United States". Once it is completed I will be sure to post a link here and give some more information about it... My plan is to have it fairly well finished over Thanksgiving break next week, meaning only touch-ups have to made before it is ready to be presented on Dec. 8th. A few other school projects were mixed in last week, and then throw in the GRE (Graduate School Admissions Test) to finish off the week with enough stress for the entire semester!

This week is calmer, with the looking forward to next weeks' long vacation to get work done. Nonetheless, still plenty to be done before I can really relax and get into some great forecasting.

I will likely have another update later this week or very early next week pertaining to a photo book that I will be releasing. So if you've enjoyed some of the photography that I've had on here before, and are looking forward to some new pictures be ready to purchase this book! It will likely be available in both hardcover and softcover, and be a 10x8" book full of high quality color pictures!

As for the weather, the lows on Tuesday morning were definitely in the chilly category ranging from 11 degrees in Spencer and Estherville to the lower 20s in a few southern locations. This mornings' temperatures were much better in the mid 20s to lower 30s, but a cold front currently sweeping across the state hamper the highs for much of the state. Windy and chilly conditions for the latter half of the week mean some wind chills that most will not enjoy. The forecasts are also leaning to a brief system that will likely sweep down through the state on Friday night. With limited moisture and its' quick movement, it isn't likely to be anything special, but with the cold temperatures we'll definitely see some snowfall with minor accumulations being possible for parts of the state.

Cold Night Ahead...

With clearing skies and calming winds over the state tonight due to a high pressure not too far away, we'll see some cold temperatures tonight across the state. Lows are likely to range in the teens across most of the state, with near 20 lows near the Missouri. The coldest temperatures should be in northeast Iowa, where a few may see lows in the lower teens. The clear skies will also let temperatures warm up fairly nice on Tuesday, highs from the mid 30s to upper 40s from northeast to southwest. A few clouds will move in before Tuesday night, keeping lows a little warmer, ranging in the lower 30s to upper 20s from west to east. Wednesday's highs will keep the warming trend continuing, mid 40s in northeast Iowa to the mid 50s in southwest Iowa. Wednesday night lows in the lower 20s to near 30 from north to south as the clear skies continue.

With the nice weather expected for the rest of the week, we aren't looking at any sort of weather through at least Friday. Some weather models have shown the potential for a storm system to come in for the weekend, but others continue our fairly boring weather pattern...

Holding off Winter...

We've made it through another system with little snow accumulations across the state. A few of the past storms have accumulated snow in some areas of Iowa, but these snowfalls thus far have only lasted a day or two. With the next system not in sight for another week, we'll have at least one more without the white stuff on the ground. Temperatures may not be too warm, but nobody should be complaining too much as this point.

Scattered flurries are possible tonight and into tomorrow with the cold air moving in aloft. Otherwise windy conditions and chilly temperatures will provide the football games tomorrow an opportunity for the fans to bundle up. Lows tonight in the mid 20s to mid 30s from northwest to southeast. Mostly cloudy skies tomorrow, highs only in the mid 30s for much of the state with a few places in the west getting slightly higher as clouds begin to break up during the late afternoon hours. Windy conditions will also prevail over the state, with winds of 15-25 mph and higher gusts continuing into the evening hours. With the skies clearing on Saturday evening, and a let up in the winds, temperatures will drop into the lower and mid 20s!

We'll end out the weekend with a upper level trough beginning to move away from the plains. This will allow for a pretty good spread in temperatures from southwest to northeast. Sunday highs in the mid 50s in the extreme western parts of the state, with highs only near 40 in the northeast. Overnight lows on Sunday in the mid to upper 20s from north to south... As we head into the week ahead, look for mainly clear skies and temperatures in the 30s and 40s for highs; 20s and 30s for lows.

Another Round... Rain Only?

The forecast for Tuesday's weather system wasn't completely on target, especially the Tuesday evening into Wednesday prediction of the potential for more snow. Many in the northern third of the state woke up to some snow on the ground Tuesday morning, with some areas receiving up to an inch on the ground. Other parts of the state did see a mix of rain, sleet, and freezing rain overnight that allowed a few roads to get slick enough for hazardous travel. Over the course of the day the temperatures rose and we didn't see too much besides rain across the entire state, and even as nightfall arrived the temperatures were just not cold enough and the system too weak to produce any additional snowfall across the state.

Now looking ahead, as the next system approaches the state we are left with warming temperatures with the potential for even above average readings across most of the state. This should allow this next system to contain rain only for the state during the bulk of its' precipitation. As the system exits and cooler temperatures move in behind, any lingering shower may be able to produce some snow. A quick look at the forecast with this storm system:

Highs on Thursday ranging from the lower 50s to the mid 50s from north to south across the state. Expect showers to move across the northern two-thirds of the state through the daytime hours, with only scattered showers for the southern portion. Overnight on Wednesday, expect the showers to move into mainly eastern Iowa with only lingering sprinkles left for the rest of the state. Lows should range from the mid 30s to lower 40s from west to east. Lingering showers/flurries could be seen on Friday and Friday night, highs from near 40 in the northwest to near 50 in the southeast. Lows overnight dropping into the mid 20s to near 30 from northwest to southeast as well...

An updated weekend forecast may be posted later Friday afternoon...

Mixed Bag...

A decent storm system is spinning over the central plains states, bringing rainfall to much of the plains states. A few severe thunderstorms, even a couple tornado warnings, are ongoing over Texas and previously in Kansas. The event for Iowa is just beginning, as one weakening band of rainfall is moving through southwest Iowa and should continue to move northeast into the early overnight. Additional bands of rain are currently over Kansas and Missouri and will move north overnight along with the low pressure system. This precip that is currently rain will move into a little cooler air at the surface, leading up to the possibility of sleet and freezing rain for a portion of the state. As the cool air continues to build in the atmosphere thanks to both strong updrafts (adiabatic cooling) and a lot of falling precip (evaporative cooling) we could see more snow over the northern third of the state. This additional cool air may also allow areas that currently are only expecting rain or freezing rain to see some quick bursts of snow. Essentially there are a lot of scenarios playing out with this storm system, meaning that you should be prepared for anything come tomorrow!

Temperatures were held a little cooler today than expected, which leads to discussion on the better potential for freezing rain tomorrow morning. A lot of information could be thrown out on how freezing rain is more likely even though temperatures have been below or around freezing throughout the past 48 hours. Warm air aloft, cold surfaces, cooling due to strong lift or precip falling, etc. all could lead to different scenarios. I'll just go into the current forecast for the next 36 hours and we'll see how well it works out over the course of tomorrow:

Tonight's lows will range from the mid 20s to the mid 30s from northeast to southwest, the lows will be kept higher over a majority of the state due to the cloud cover that has already made its' way in. As previously mentioned, the rain showers over southwest Iowa will slowly move over parts of western and central Iowa early tonight. Additional rainfall, freezing rain, sleet, and some snow, will move into the western half of the state before sunrise. The rain will continue to expand and increase across the entire state throughout the day on Tuesday. So the question isn't if you'll get the precip, but rather what kind of precip you'll get. Currently it looks like areas north of highway 30 will be in the area of freezing rain and sleet, with some rain by mid-afternoon. Once you go north of highway 20 then you'll be cool enough to see the freezing rain and snow, with accumulations fairly likely. The precip will begin to move out Tuesday night as the overall strength of the system weakens, and by the end of morning on Wednesday we'll see the all clear for precip. Tuesday night temperatures in the upper 20s to mid 30s from northwest to southeast...

In the end, snow accumulations north of highway 20 should range from a dusting to near 2 inches. Areas to the south may see a dusting at most, with some bursts of snow being possible. Freezing rain accumulations shouldn't be significant, likely under a tenth, but even a few hundredths is enough to create hazardous travel. Rainfall amounts over the southern third should be a few tenths to near a half inch total. Plenty of different scenarios, so we'll see how this plays out... Just be prepared for some slick conditions across the state for tomorrow and tomorrow night.

More Snow?!?

After Thursday night and Friday's snowfall across the state, we saw more snow flurries and some light freezing rain across the state over the weekend. Temperatures across the state were also representative of winter's arrival as the highs today ranged from the mid 20s to mid 30s across the state. With another storm system arriving for the early half of this week, we'll see the chance for another winter storm mix across the state. A quick forecast update for the first half of the state is below:

Tonight's low will range from the mid teens in northwest Iowa to the lower 20s across the rest of the state. Monday highs will range from the lower 30s to lower 40s from northwest to southeast as clouds begin to stream in from the south. Monday night will see temperatures range from the mid 20s in northeast Iowa to the lower 30s across the southwest half of the state. The warmer temperatures in the southeast will be due to the cloud cover and precipitation that is likely. A mix of rain and snow is possible throughout the nighttime hours, with the rain/snow mix continuing until Tuesday afternoon as it warms enough to make a majority a cold rain. The precip should move across to include nearly all but the extreme northeast part of the state by Tuesday afternoon. A mix of rain/snow continues in the forecast for Tuesday night, temperatures from the mid 20s to mid 30s from northwest to southeast. We'll finally clear out by Wednesday for the western half of the state, with highs increasing to the 40s across the entire state. More details on the precip type and any potential accumulations in later updates...

Accumulating Snow!!

It's quite late, and with work starting up in less than 8 hours I just don't see the time to make a large update. Essentially to recap this strong weather system so far, we saw the thunderstorms move through the state prompting some severe and tornado warnings in the far western sections on Wednesday night. As this rain cleared, a few additional showers continued this morning and early afternoon. Overall rainfall totals were not terribly impressive, but it was pretty good for it occurring in November. Now as the low pressure begins to slowly move east/northeast tonight and through tomorrow we will see the cold air really rush in. With some moisture lingering, and the strong cold air aloft, snow showers are in the forecast for much of the state.

These snow showers shouldn't cause too many problems for the majority of the state, as ground temperatures are still warm and with moisture also lingering on the surfaces won't allow snow accumulation to come easy. However, northwest Iowa will see this snowfall start early, coming tonight through tomorrow morning, leaving them with the best chance for snowfall accumulations. These accumulations are likely to range from 1-2 inches with isolated 3 inch amounts over northwest Iowa where a Winter Weather Advisory has been issued. Areas near the advisory should see a dusting to potentially an inch during the morning hours tomorrow. The remainder of the state will see the snow showers overtake them during the afternoon and into the evening hours. Accumulations won't be likely, but areas that can see some of the heavier bands are likely to see the ground at least turn white.

With this being the first good snowfall of the season, coming with some fairly gusty winds as well, expect travel conditions to be hampered some. I'm making a trek from Ames back home to northwest Iowa, so maybe a picture of snow is on the way to the blog for the weekend update!

Severe Weather Update #2 (Nov. 5)

A severe thunderstorm watch has now been issued for portions of western Iowa, this watch goes until Midnight tonight. A line of individual thunderstorms has developed along the cold front and has rapidly gained severe weather characteristics, with the potential for large hail and damaging winds. The threat will likely continue as the storms move north/northeast through the evening hours.

For more information on the Severe Thunderstorm Watch: SPC Watch #925

Current Des Moines NWS Radar: Iowa Chaser Homepage

I will be heading down to the Des Moines NWS, thus this is the last update for the evening.

Severe Weather Update (Nov. 5)

4:56 PM Update - A severe thunderstorm warning has been issued for portions of Monona county in western Iowa. A portion of a line of severe thunderstorms capable of damaging winds and severe hail will move into the state over the next 45 minutes. This will likely be the first of a few severe thunderstorm warned cells to make its' way into and through western Iowa this evening/tonight.

4:50 PM - Although the main focus for severe weather is likely to be over Kansas and Oklahoma, moving into Missouri and potentially portions of Arkansas early tonight; we'll likely see the chance for a severe storm or two across western Iowa this evening and tonight as well. Current radar shows a line of storms developing along the cold front that is oriented north/south near the Missouri River. These storms have been fairly slow to develop, but are showing signs of strengthening. As these storms move off to the north/northeast, they will slowly propagate into all of western Iowa within the next hour or two.

As the storms move through the state this evening and into the overnight hours, expect gusty winds and frequent lightning to go along with some very heavy rain at times. Through 10 PM a few storms may be capable of marginally severe hail and gusty winds, although a tornado or two cannot be completely ruled out. Beyond 10 PM, additional thunderstorms moving through Missouri will also begin to enter southern Iowa bringing heavy rain and some thunder. The line of storms will make its' way through the state and into eastern Iowa by the early morning hours, and out of the state by early afternoon. Beyond this line of showers/thunderstorms, additional precip behind the low pressure system to our north is possible on Thursday night and Friday, a rain/snow mix is possible for some portions of the state why the majority of the state may see snow showers through much of the time on Friday. Accumulations right now appear to be minimal if any, but this could be the first sign of winter for much of the state.

Updates tonight will not be likely, as I will be completing a part of my internship down at the National Weather Service in Des Moines while the potential for severe weather rolls through the state.

Wednesday Severe Weather

A strong lee cyclone will continue to move eastward tonight and through tomorrow, situating itself near the Nebraska/South Dakota border by mid-afternoon. This low will begin to occlude with the development of a potential secondary low near the KS/NE borders tomorrow afternoon as well. As the low occludes, it will begin to move off to the northeast into central Minnesota by Thursday night. As the low slowly moves off to the east/northeast, a secondary trough may slide through the state and allow more rain, possible snow showers for Thursday night into Friday.

As for the severe weather threat, it appears the timing of the frontal passage will be too late for Iowa to see a significant severe weather threat. However, the western half of the state will still likely be in a slight risk for severe weather as the late evening and early overnight thunderstorms that move into the state will be capable of damaging winds and large hail. The tornado threat will be there tomorrow, but will likely be along and just west of the I-29 corridor including southeast South Dakota, eastern Nebraska, and points southward. These storms that develop/evolve into the state during the evening hours may be capable of a tornado or two by the forecasts at this point, however the main threats for the western half of the state will be for damaging winds and some marginally large hail.

Just to the south of the state, a large squall line may evolve along the I35 corridor in KS/MO and even further southward. This line may move northeast, and according to some weather models this line may move into central Iowa from the south giving mainly a threat at significant rainfall. This potential line, along with other showers and thunderstorms from the west will move over the state throughout the nighttime hours. As the low occludes, we will likely see a dry slot move into the state and allow us to at least be dry for most of the day on Thursday. As mentioned with the additional trough moving in Thursday night, additional chances for a mix of rain/snow will come with it. More updates are possible tomorrow afternoon on the evolution of a potential severe weather threat.

Midweek Thunderstorms & Their Severe Weather Risk

Before getting into the detail of thunderstorms for midweek, a quick recap on what was a sunshine-filled day with record setting high temperatures for the second straight day in November! Highs ranged from the lower 70s in extreme eastern Iowa to the lower 80s across extreme western Iowa. Record highs were officially set in Atlantic (77), Mason City (75), Dubuque (73) and the record was tied in Des Moines (76); not to mention several other records just outside the state of Iowa. Expect temperatures tonight to only fall into the lower and mid 50s, with a few upper 40s possible in northwest Iowa. Tomorrow's highs may be hampered some by scattered clouds, but near record highs in the lower to mid 70s throughout are still expected.

A low pressure forming off the Lee of the Rockies should push into the Dakotas Tuesday afternoon, and continue moving east overnight. This low will be aided by the development of a warm front that will likely drape across portions of northwest Iowa Tuesday night. This warm front may lead to some showers and thunderstorms across the western half of the state, but the chances are still fairly low. Overnight low temperatures should range from the lower 50s to upper 50s from east to west. As this warm front lifts north by the morning hours, expect strong southerly winds to bring in moisture and warmth ahead of a strengthening cold front to the west of the state.

Models are trying to come together on a solution for the surface low pressure, the frontal position, and overall severe weather threat for the plains states. The latest WRF model has came inline with what the GFS and other models have shown with the surface low lingering over southeast South Dakota by 00z (6 PM) Wednesday. A cold front and dryline will be the focus for thunderstorms along and south of the low through eastern SD/NE/KS and OK. With strong wind fields throughout the plains, the shear should be no problem, nothing unusual for either spring or fall systems. Moisture should be in the mid 50s to near 60 along and just ahead of the fronts from SD southward through OK. The combination of both moisture and warmth at the surface, and cold air aloft should allow for moderate instability over NE/KS/OK and points just east. Although the mode of severe weather is somewhat in question still, I do believe that all modes (damaging winds, large hail, and tornadoes) will be possible from southern South Dakota, through eastern NE/KS/OK, and then extending eastward during the early overnight hours into western IA/MO/AR.

Areas in southeast SD and northeast NE may be looking at some very strong low level shear values with their proximity to the low. Combined with the strong cold air advection aloft, the instability should be sufficient to warrant a low topped supercell event with tornadoes possible. Further south, isolated storms may develop during the late afternoon warranting the risk of hail/wind/tornadoes. Eventually, we may see the development of a large squall line from Iowa southward through Arkansas with the cold front/dryline surging eastward overnight. Continued risk of damaging winds and some large hail are going to be possible with these storms overnight... More updates on the severe weather risk are likely in Tuesday's blog update.

Beyond the potential for thunderstorms and severe weather, high temperatures on Wednesday in the mid 60s to lower 70s from northwest to southeast. Wednesday night lows from near 40 along the Missouri River to the mid 50s in eastern Iowa. Thursday highs in the mid 40s to lower 60s from west to east as the cold air continues to push into the state. By Thursday evening we'll see the transition to snow showers become possible over northwest Iowa. This potential for snow showers will continue to expand over the western half of the state Thursday night as lows range from the upper 20s to upper 30s from west to east. The potential for snow, and even some wintery conditions over the northwest quarter of the state will be discussed beyond the severe weather threat.

Very Warm... & Thunderstorms

High temperatures today were able to reach the 70s throughout most of the state, although some cloud cover kept the eastern portions of the state slightly cooler. And a weak boundary also kept the warm air from reaching too far east. The mid to upper 70s were prominent in the western third of the state, where record highs were being challenged. One confirmed record high came from Estherville, where the high reached 76 degrees, breaking the old record of 75. Other records may end up being tied, they were at least within a few degrees.

The warm air will continue tomorrow, in fact with near record temperatures once again occurring across a majority of the state this time around. We'll start out tonight with lows in the lower to mid 50s, as increasing moisture may also lead to some fog development. Tomorrows highs will be in the mid 70s throughout the entire state, but expect some localized areas to reach the upper 70s. These highs will accompany dewpoint increases well into the 50s as southerly winds begin to push moisture up from the south. Monday night lows will be hampered in the northwest as a weak cold front slides in and stalls out overnight. Mid to upper 40s over northwest Iowa, while lower to mid 50s will cover the rest of the state. Tuesday highs won't be quite as warm, but still well above average in the lower to mid 70s across Iowa. The main reason for the lower temperatures on Tuesday may be due to some increase in clouds, and gusty southerly winds of 10-25 mph. Tuesday night will begin to bring in some precip chances for mainly northwest Iowa, however, these precip chances may be taken out depending on timing issues with the storm system entering the state. Tuesday night lows will range from the lower 50s in the east to the upper 50s in the west under cloud cover.

Beyond Tuesday night the forecast really gets interesting with talk of the first big Fall severe weather event for the state of Iowa. A strong low pressure system will develop off the Rockies and move into the plains with an associated strong Canadian trough. The combination of strong southerly winds, bringing in heat and moisture, and this strong frontal system and associated low will bring in likely chances of thunderstorms. Given the good instability and shear also present, the severe weather threat is also present. The most recent discussion from Des Moines NWS touches on the possibility of all modes of severe weather, including tornadoes. This event may likely end up being what is termed a cold core low severe weather setup, where low topped supercells that may have fast movement are able to rotate rapidly and bring in the chances of tornadoes. This risk has been on the rise as weather models are coming into an agreement with a strong low tracking near or through the state of Iowa. More details on the severe weather threat will be discussed in updates on Monday and Tuesday as the event nears.

Beyond this severe weather event, as the low wraps up to the east of the state we will see a strong influx of cold air. With precipitation lingering, many of the NWS offices have decided to include the risk of a mix of rain/snow chances for Thursday night into Friday morning. So the potential for severe weather, followed by snow showers within 24 hours, is definitely there for the state. The risk of snow will also be discussed in midweek updates, most likely after the severe weather risk is detailed.

Wonderful Weekend!

Just when you think we might be getting into the thick of Fall and see the temperatures really tumble down, we get a week like this week has been. Although cold in the first half, we've warmed up very well and featured highs in the 70s across much of the state today. These above normal temperatures look to remain over the state through the weekend, allowing everybody a great opportunity to enjoy the nice weather at least one more time before the chilly temperatures return for good...

Highs for Friday will range from the mid 60s to near 70 from north to south across the state. These lows are slightly cooler with the weak cold front that will be entering the state, although likely stalling and becoming fairly diffuse over central Iowa. Friday night lows may have a wide range with some cloud cover possible over eastern Iowa. Either way, lows will range from the upper 30s to upper 40s from west to east. Saturday high temperatures will vary across the state with some clouds hampering highs over the northeast, but winds turning southeast will help the temperature rise slightly in western Iowa. Highs from the mid 50s in northeast Iowa, to the upper 60s over the southwest quarter of the state. Saturday night lows will be in the mid 40s to near 50 across the state, with some clouds keeping it mild. We finish of the weekend with Sunday highs in the mid 60s over northeast Iowa, to the upper 60s and near 70 across the rest of the state. Sunday night will have upper 40s and low 50s for the state, and we'll continue the mild temperatures into early next week before the next storm system arrives with a chance of rain!

2009 Weather Calendars!

The Iowa State student chapter of the American Meteorological Society has completed our 2009 Weather Calendar! This is our main fundraiser for the year, in which the proceeds go towards several of the community outreach events that we do such as elementary school talks. The calendars are printed on glossy, card stock paper, and feature great images that were all taken by our members! Four of the images in this years' calendar are taken by yours truly, including the front cover photo.

If you wish to order a calendar, please email me at jaysonprentice(at)gmail.com or check out the web page that has been setup on our site.

http://www.meteor.iastate.edu/ams/calendarinfo.php

Thanks!

Above Average Temperatures!!

At least for the highs for the remainder of the week, we'll see above average readings for nearly the entire state. The lows will hover from near normal, to above normal for the remainder of the week as well. The latter half of the week will see clear skies, making what appears to be a great Halloween night for the entire state.

Lows tonight will range from the mid 20s to lower 30s from north to south across the state. Highs tomorrow will be in the mid 50s to mid 60s from east to west, as winds begin to become southerly to bring in even more warmth. Wednesday night lows in the mid to upper 30s across the state, with clear skies remaining. Thursday really warms up with southerly winds picking up 10-20 mph and some higher gusts. Highs in the lower 60s in northeast Iowa, to near 70 across the south and west. Thursday night is beggars night for many local communities, the evening forecast should see temperatures in the 50s and winds around 10 mph. Lows for Thursday night will be in the upper 30s to mid 40s from northwest to southeast as a cold front begins to enter the state overnight. This cold front will hamper the high temperatures on Friday, with a few clouds finally making the forecast as well. Highs from the lower 60s to upper 60s from north to south, as winds shift to the northwest as the cold front passes through. As we enter the weekend, Friday night lows will be in the mid 30s to lower 40s from north to south.

More details on the Halloween forecast, and the entire weekend in Thursday's update!

Severe Local Storm Conference Papers

The American Meteorological Society's Severe Local Storms Conference got underway today in Savannah, Georgia. This conference features nearly a full week of presentations about every type of severe weather imaginable, from hail, lightning and tornadoes, to hurricanes and climate relations to severe storms. I was not able to go to the conference this year, but have read through several of the papers that are available online through the AMS. I thought I'd share with you some of the ones that I have found interesting, these include the talks about TWISTEX 2008, the summer research project that I have been a part of the past two years. Another paper is on the Parkersburg, IA tornado which many people may enjoy to at least look at. Of course I will also be happy to share with you a paper that I am a co-author on! If you have any questions about the papers, please leave a message here or email me (jaysonprentice(at)gmail.com).

Synoptic environments and convective modes associated with significant tornadoes in the contiguous United States
by Thompson, Grams, & Prentice

TWISTEX 2008: In situ and mobile mesonet observations of tornadoes
by Karstens et al.

Thermodynamic and kinematic analysis near and within the Tipton, KS tornado on May 29 during TWISTEX 2008
by Lee, Finley, & Samaras

Mobile mesonet observations of an intense RFD and multiple RFD gust fronts in the May 23 Quinter, Kansas tornadic supercell during TWISTEX 2008
by Finley & Lee

The Parkersburg, IA tornado
by Marshall, Jungbluth, & Baca

Windy & Chilly!!

After a cold front moved through last night, additional cold air was pushed into the state as a Canadian high pressure system scooted in behind the cold front and associated low pressure. These two pressure systems combined to give much of the plains some strong gusty winds today, and Iowa was definitely in the mix with a high wind warning issued for much of the state for this morning and afternoon. Wind gusts across the state were in the 50s and even 60s (mph), with sustained winds 35-45 mph. These winds have weakened with the sunset, and are currently only 20-30 mph with gusts up to 40 mph. Besides the wind today, the temperatures which started out near 50 at midnight have continued to fall throughout the day despite the sunshine. The air aloft is cold enough that even surface temperatures near 40 are enough to create sporadic snow flurries across the state. Ames did see some snow flurries between 6-7 PM, and other portions of the state will continue to see these flurries through the overnight hours.

With the cold air from Canada rushing onto the plains states, you can expect that the temperatures for the next day or so will not be very warm. Tonights' lows will be kept a little warmer due to the winds, but will still results in a widespread freeze for the entire state (the first of the year for the entire state). The lower 20s are likely in northwest Iowa, and only the upper 20s for the 'warm' southeast portion of the state. Tomorrow highs will range from near 40 in the north to the mid 40s in the south despite the sun being prominent throughout the day. Overnight lows on Monday will be the coldest of the season by far, with the teens in northwest Iowa and only the mid 20s in southeast Iowa.

As winds switch to the west and southwest Tuesday into Wednesday we will start to see a nice warm-up. Tuesday highs in the mid 40s over northeast Iowa to the mid 50s over southwest Iowa. Overnight lows in the mid 20s to lower 30s from northeast to southwest across the state. The winds really shift to the southwest on Wednesday, continuing to bring in the warmth with highs in the mid 50s to mid 60s from northeast to southwest. Upper 30s to lower 40s across the state on Wednesday night will finally get the entire state above freezing for a 24-hour period.

We'll warm up even more for Thursday, but another cold front coming down will keep the highs down for your Halloween weekend. A first look at your trick-or-treating forecast shows temperatures near 50 to the mid 50s from north to south across the state by 8 PM on Friday. More detail on the latter half of the week and Halloween forecast in later updates!

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