Thursday, February 26, 2009

Winter Storm: Feb 27-28

Another round of winter weather is likely to effect at least the western half of the state tomorrow evening and overnight. Eastern Iowa will likely be spared, with only flurries and cloudy skies as they head into the weekend. As for the western half, a shortwave in the mid-levels will spark off some additional snow-showers tomorrow afternoon over the Dakotas. These snow-showers will move southeast with time tomorrow, following an axis close to the Missouri River. With cold temperatures in place, this will be an all snow event throughout the northern plains. Snowfall totals should range from 2-4 inches through the eastern half of Nebraska, and much of the western half of Iowa. A few areas may be able to sneak by with a little less, and others a little more (up to 5 inches).

Beyond this storm system, we look to stay dry until late next week...

Winter Storm: Feb. 26 Recap

The bulk of the storm has moved off into the Great Lakes region, with some lingering thunderstorms across the central plains (MO/AR). Behind the system, strong northwest winds along with some lingering precipitation are still creating some hazardous conditions. Those that received several tenths of freezing rain today are now seeing some power problems due to the winds bouncing the power lines. Road conditions currently indicate that much of north-central and northwest Iowa has ice/sleet covering them. Parts of northern Iowa may see some light to moderate snow overnight as the wrap-around precipitation from the strong low moves to the south out of Minnesota.

The Des Moines NWS did not receive any significant reports of ice accumulation and sleet, with many areas receiving less than a tenth of an inch of ice or less than a half inch of sleet. The more impressive reports may have been with the up to an inch diameter hail that fell within the Des Moines metro just after Noon. You can read the entire summary of their local storm report's here: Des Moines NWS LSR's

Sioux Falls NWS and northwest Iowa received some more impressive amounts, with nearly a quarter-inch of ice accumulation near Spencer this morning. A new report this evening from Spirit Lake mentions that they have just over an inch of snow with a glaze of ice as well. You can read the Sioux Falls NWS listing of local storm reports here: Sioux Falls NWS LSR's

Both Omaha and Davenport NWS offices saw mainly rain across their region, thus the lack of winter-type reports. Some heavy rain reports, and hail reports came in with the thunderstorms that moved across their forecast areas. The NWS office in LaCrosse that covers parts of northeast Iowa saw mainly snow today, with the greater amounts in Minnesota and Wisconsin. All of the Iowa reports looked to be under 2 inches of snow...

Look forward to the next storm system that will begin to effect the state already tomorrow afternoon! Details in the next update...

Winter Storm: Feb. 26 Update #3

Thunderstorms are the key to todays' weather, with thunder being reported throughout the line of precipitation from southern Minnesota through central Iowa. North and along of Highway 20 reports of thunder-sleet and thunder-snow are coming in, while south of Highway 20 the precipitation is falling as rain. Beyond this line of thunderstorms is the cold front, indicating a likely end of precipitation and this winter storm for the most part. Total accumulations are likely going to be near expected for most areas in the north, perhaps just under the forecasted values given current reports.

Eastern Iowa will see continued thunderstorms throughout the afternoon, with some potential of severe thunderstorms over southeast Iowa. Once again, portions of the north will see sleet and snow, perhaps some freezing rain; while areas in the south see rain throughout this event. Additional updates are possible throughout the afternoon...

Winter Storm: Feb. 26 Update #2

A very brief update on the ongoing both winter and severe weather over western Iowa. Freezing rain has become a major problem across much of northwest Iowa this morning, with many roadways already being reported completely covered with ice. These conditions are not likely to improve as precipitation is expected to continue for the next few hours over those locations. Expect this precipitation to move east/northeast with time this morning, making it near the I-35 corridor by the Noon hour across the northern half of the state.

Also of concern this morning is severe weather... On the southern edge of the precipitation there has been a few thunderstorms, one of which has become severe with the capabilities of producing penny sized hail. Several reports were received near Onawa and surrounding areas of this penny sized hail... An additional storm has also become severe in Pottowattamie and Shelby counties, also capable of 3/4" hail.

Reports now coming in on how much freezing rain has accrued so far, and also how much sleet has fallen in some areas. A very tricky forecast remains with rain turning to sleet/snow, and freezing rain and sleet falling throughout the north with snow soon to come. Additional updates are possible around Noon and later in the afternoon...

Wednesday, February 25, 2009

Winter Storm: Feb. 26

Another winter storm with all forms of precipitation is expected to impact the state of Iowa beginning early tomorrow, and continuing into Thursday night. Areas of the state will see just rain, others rain and snow, and some freezing rain, sleet, and snow! Travel conditions are likely to be hazardous throughout the day no Thursday across roughly the northern half of the state with ice, sleet, and snow all likely.

Precipitation will begin across the state around sunrise tomorrow for much of western Iowa, and will quickly continue to cover the entire state by Thursday afternoon. Western Iowa will begin to see an end to the precip by evening, with eastern Iowa seeing and end towards midnight. The highest precip totals are likely to remain over the southern half of Minnesota, and southeast Iowa. These two areas are likely to see only one precip type, snow over Minnesota, and rain over southeast Iowa. Between I-90 and I-80 is another story, with the potential for significant icing making headlines towards the Highway 20 corridor. Weather models continue to be in fairly good agreement between the type of precipitation likely over areas of the state, however, there will have to given some leeway until the precipitation begins and the temperatures at the surface and lower levels dictate what type of precip actually does fall.

An update to the forecast will be posted later tonight, however, at this time some areas are likely to see 2-5 inches of snow across northwest and extreme northern Iowa. Other areas along the Highway 20 corridor will not only see 1-3 inches of snow, but potentially a tenth to quarter of an inch of ice accumulation. Between Highways 20 and 30, a tenth of an inch of ice is possible with a mix of rain/snow as well. Those south of Highway 30 are likely to see mainly rain, although some snow may mix in towards evening hours. A complete update and summary of precipitation types and totals are likely tonight.

Winter Storm: Feb. 25 Update #1

Forecasts are continuing to converge onto a solution for tomorrows' winter storm and the NWS offices have changed the Winter Storm Watches to different advisories and warnings. A very complex forecast still with any slight changes not only in surface temperatures, but temperatures just above the surface changing the type of precipitation received. Once again all modes of winter precipitation are forecast across some part of the state...

Areas of southeast Iowa currently under No Advisory/Warning are expecting mainly rain during the morning and afternoon hours, with a slight chance of a sleet/snow mix towards the evening hours for areas nearest to the advisories.

Those currently under a Winter Weather Advisory, north of a line from Denison to Ames to Waterloo and to LaCrosse, WI. Some rain may be possible early in the south, otherwise a mixture of freezing rain and sleet likely through the morning and early afternoon. Total ice accumulations of one to two tenths of an inch possible, with 1-3 inches of snow/sleet also possible.

Parts of north-central Iowa are under a Winter Storm Warning, where freezing rain is likely to begin during the morning hours. By mid-afternoon this freezing rain will begin to turn to sleet and finally all snow. Total accumulations include one tenth to a quarter of an inch of ice; and 2-4 inches of sleet/snow.

Just north of the state, precipitation should fall as snow throughout the event leading to significant snow accumulations. A total of 4-8 inches is likely throughout southern Minnesota, eastern South Dakota, and into Wisconsin during the overnight tomorrow. Additional storm updates are possible tomorrow to update any temperature changes, and their effect on precipitation type.

Tuesday, February 24, 2009


Temperatures today and tomorrow will once again feel like spring is on the way. Highs today should range from near 40 in the northeast to the upper 50s in the southwest; and from the lower 40s to upper 50s tomorrow. Lows tonight in the mid 20s to lower 30s should be expected as clear skies will allow plenty of cooling still. Beyond Wednesday the weather once again turns to a late winter scenario with rain and a few rumbles of thunder possible in the south, rain/freezing rain and snow, and all snow in the north. In other words, a messy situation is in the forecast for Wednesday night through Thursday for much of the state.

Precipitation should begin over the southwest half of the state on Wednesday night or early Thursday, and continue throughout the day on Thursday; even into Thursday night for the eastern third of the state. Lows Wednesday night should be in the lower 20s across the north to the mid 30s in the south. Highs on Thursday are expected to range from near 20 in the northwest, to the lower 40s in the extreme southeast. As the entire state moves into the cold sector late Thursday, overnight lows on Thursday night may range from near zero in the northeast to the lower 20s in the south.

With the complex and wide range of forecasted temperatures, it puts several questions in the forecast for precipitation type across the state. It does appear that much of the northern third will see snow throughout the system, leading to anywhere from 2-6 inches of accumulation. Between Highways 18 and 30, there definitely seems to be potential for freezing rain as well with lower levels warmer to above freezing while surface temperatures remain at or just below freezing. With many varaiables still uncertain, the amount of ice accumulation is a big question, but does appear that it could range from just a glaze to a tenth of an inch or more. For the southern third, most precipitation looks to fall as rain as temperatures stay well above freezing as the precip nears its' end. Some snow may mix in very late with any lingering showers, but little accumulation appears likely at this time.

Enjoy the two days of warm weather, we'll look to more winter weather by Wednesday night.

Friday, February 20, 2009

Winter Storm: Feb. 20-21

The quick clipper that was expected to bring a quick snowfall to much of northeast Iowa has taken shape and appears to pack a decent punch for the early half of this weekend. Models and NWS forecasts agree on the northeast half of the state seeing an inch or more of snowfall accumulation during the night and early tomorrow. Parts of the state may see 3-6 inches of snow during the overnight, mainly for east-central Iowa, where this snow may also pose travel problems well into Saturday due to blowing and drifting. For the snowfall accumulations of 3-6", a Winter Weather Advisory has been issued, while areas that are expected to see this snowfall and maybe slightly higher localized amounts with the blowing snow a Winter Storm Warning has been issued.

The snow should come to an end by late Saturday morning, and allow sunny skies for much of the weekend. Temperatures are likely to remain near or below freezing until Monday when a warm-up beings. Mid-week temperatures could be well into the 40s and even 50s across parts of western Iowa!

Thursday, February 19, 2009

Small shots of Winter...

This past Monday/Tuesday's weather system didn't create too much havoc across the state, with only minor accumulations of snowfall or ice. Rain was much more common throughout the length of that storm system, with most places receiving a few hundredths of an inch of rain through Tuesday morning. Between systems now, with strong northerly winds yesterday and just slightly lighter winds today and temperatures that have been well below freezing and wind chills once again back below zero.

The next storm system to come across the state should do so on Friday and Friday night, and linger into early Saturday for parts of eastern Iowa. This clipper will bring in chances of mixed precipitation across the southern third of the state, but mainly snow for the state of Iowa. Total snowfall accumulations are in limbo currently, although models have seem to come to an agreement of a 3-6" band of snow that is most likely across the northeast quarter of Iowa. Other parts of the northeast half of the state could see 1-3" through the overnight on Friday, while parts of the state only see a dusting when they awake on Saturday.

A busy week and weekend ahead, next weather update likely early next week...

Saturday, February 14, 2009

February Winter Storm(s)

Just a quick update with a recap of yesterday's snowfall totals, and a look at the next winter storm that may effect our area come Tuesday into Wednesday. Below is an image of the snowfall totals across the state, with the heaviest areas near Omaha/Council Bluffs, and then also near Des Moines. Traveling was trecherous yesterday with snow melting and re-freezing on roadways... This snow looks to stick around for a while, at least until our next winter storm can add to the totals.

The next winter storm is taking aim at Iowa once again. Significant snowfall is a possibility, but also is the chance of mixed precipitation over the state with rain/snow mixtures. The latest graphic from the NWS shows their initial thoughts, later updates will address this winter storm.

Thursday, February 12, 2009

Winter Storm: Feb. 13-14 Update #2

A quick update this morning on what you can expect for snowfall totals through this evening. A Winter Storm Warning is in effect for areas of southwest Iowa where snowfall may begin this morning and continue through the afternoon hours. Total accumulations of 4-7 inches are likely, with some locally heavier amounts. Other parts of south-central Iowa have been put under a Winter Weather Advisory as snow will begin this afternoon and continue through this evening leaving 2-5 inches of snow on the ground.

Other parts of the state may see snow, but little accumulation is expected. Traveling may still be hazardous over areas of the state with the snowfall, thus be alert when the snow is falling as it may be heavy at times.

Beyond this snow, expect a fairly clear and sunny weekend with temperatures in the 20s and 30s across the state for highs, and single digits to the teens for lows. The next chance of precipitation will come next Tuesday as the chance for a wintery mix enters the forecast.

Winter Storm: Feb. 13-14 Update #1

The storm totals with the upcoming winter storm are in limbo with the latest model runs backing down on total snowfall accumulations. This afternoon's latest runs continued to back down on snowfall amounts, the NAM specifically took the storm even well below warning criteria. With the system coming together rather quickly over the central plains, and falling apart even faster during the afternoon hours on Friday it is likely that much of the state will not see greater than 4 inches of snow. Areas of southwest Iowa have been put under a Winter Storm Warning and will likely see 4-7 inches of snow by Friday evening. Other areas across southern Iowa will likely see 2-6 inches of snowfall, with isolated amounts in the 8-10+ range. These isolated higher amounts will be caused by elevated instability, which will likely create bands of thundersnow that will accumulate snow quickly during the afternoon/evening hours. Once north of Highway 20, total snowfall accumulations should be under 3 inches, with the Iowa/Minnesota border receiving little if any snow from this system.

Expect other parts of southern Iowa that are currently under at Winter Storm Watch may only be upgraded to advisory criteria with mentioning of isolated areas receiving significant snowfall. Another update is likely later tonight...

Wednesday, February 11, 2009

Winter Storm: Feb. 13-14

For the past 36 hours the eyes have been on this upcoming winter storm that will move a low over northern Missouri, putting southern Iowa in the favorable spot for receiving significant snowfall accumulations. Forecast models have continued to show a similar track throughout their latest runs, and continue to show snowfall accumulations of 6-10 inches or greater over southern Iowa. The continued forecast of this significant snow has prompted the NWS to issue a Winter Storm Watch for the entire state south of Highway 30.

As a low pressure system forms over western Kansas/Oklahoma during the nighttime hours on Thursday, the low should move to the northeast through northern Missouri on Friday. Snow should begin along the western borders of Iowa during the early afternoon hours, and spread across the entire state by Midnight on Friday. The snow should begin to taper off over western Iowa by sunrise on Saturday, and end by Noon on Saturday throughout the state. Total accumulations should be in the 6-10 inch range for areas south of Highway 30 to near the IA/MO border, with areas between Highway 30 and Highway 20 also receiving 3-6 inches. Within the heaviest amounts of snow, some isolated heavier amounts in the 10-15 inch range is easily possible. This is due to some elevated instability that will allow for the possibility of thundersnow, with 1+ inch per hour rates becoming up to 2 inches per hour in bands of thundersnow. More updates likely as Friday nears...

Monday, February 9, 2009

Severe Weather: Feb. 9 Update #2

The strong dry slot that has worked its' way through Kansas, Missouri and not well into Iowa has considerably dampened the possibilities of thunderstorms, let alone severe thunderstorms. The best risk has worked its' way to the north or right along the warm frontal boundary across northern Nebraska and Iowa, this is where despite cooler temperatures at the surface there is still some potential instability present in the lower levels. A few thunderstorms may be able to develop in this area within the next few hours, with the severe threat still fairly minimal.

The remainder of the state will see clear or clearing skies, with temperatures soaring throughout much of the state into the 50s and 60s. Strong winds are also present, a Wind Advisory was issued for the southern half of the state as winds could reach 35-45 mph later this afternoon and evening. Expect warm temperatures and breezy conditions once again tomorrow, with highs near today's or even a few degrees higher in some locations.

Severe Weather: Feb. 9 Update #1

The severe weather risks for the state of Iowa, and for the entire central plains for that matter, have been dwindling throughout the morning hours. The SPC risk has remained at slight, although the tornado risk and large hail risk were both scaled back in the Noon outlook. Latest radar shows the band of showers wrapping around the low pressure system across northern and eastern Iowa; while a strong dry slot has been working into southwest Iowa bringing in clear skies and surface warming. Further into Kansas this dry slot has mixed down drier air which will diminish the severe weather risk. However, if timing can be nailed down the clear skies will provide instability for parts of southern and western Iowa while the dry air does not have time to mix down. Still a complex situation, but the severe weather risk does seem lower than what was anticipated this morning.

An update is likely near 4 PM...

Severe Weather: Feb. 9

A low pressure system is currently located over western Nebraska, and should move east-northeast into northern Nebraska by this afternoon. A warm front is currently located from this low and stretches east/southeast across eastern Nebraska, extreme southwest Iowa and into northern Missouri. This warm front should continue to lift north today, bringing increased moisture and a little warming. This combination may yield some instability, mainly in the lower levels, thus creating a situation in which low-topped supercells are a possibility. With strong vorticity maximum working over this same area, and wind speeds being favorable both in speed and direction, rotating storms capable of a few tornadoes are possible. Strong wind gusts are also likely with these storms, especially any that become mainly linear in nature. Some moderate sized hailstones may be possible as well given the cold temperatures aloft throughout the entire state...

Currently the best area that may see these severe thunderstorms capable of damaging winds, moderate hail, and a tornado or two appear to be over southwest Iowa and nearby locations. A line of showers and possibly a thunderstorm will move through southwest Iowa and into other parts of the state this morning, and over eastern Iowa later this afternoon. Behind this line, some clearing may occur which will increase the risk of severe weather for this afternoon. A close eye will be kept on how this clearing evolves, and any changes in the risks for severe weather across Iowa...

You can view updated radar images from my website:
Sorry for the bland view, but I haven't completed all of the things I needed to yet beings I didn't expect to be seeing severe weather in February.

Short updates possible until mid-afternoon, next extensive updates expected by 4 PM.

Severe Weather Potential: Feb. 9

It is not very often for Iowa that you will be able to get the month of February and severe weather, let alone tornadoes, all in the same sentence. That is the case today as a potent storm system works' its' way up northeast through the central and northern plains. This dynamic system has very strong winds at both the lower and mid-levels which is creating significant speed and directional shear. This shear combined with fairly warm and moist low levels compared to climatology, and the cold air that is located in the mid-levels will allow for some instability. While this instability is expected to be fairly weak (<500 J/kg), it should still be enough for thunderstorms and a few severe ones at that.

With the lack of time, just a few brief notes from tonight's model runs shows good agreement and overlap between the strong shear, good vorticity maximum at 500mb, along with appreciable LI's and good 0-3 km CAPE. This combination may yield low-topped supercells across parts of eastern Kansas, northern Missouri, far eastern Nebraska and into western Iowa. With the chance of clouds and showers previous to the afternoon, the forecast is quite delicate still. However, it does appear that areas in Iowa south of Highway 30 and west of Highway 63 will see the potential for these low-topped supercells. These storms may be capable of strong winds and moderate hail, but will also likely be rotating and may produce tornadoes. Several factors will have to come together for this event, but it is something that parts of the state should keep an eye on.

Other parts of the state may still see thunderstorms, however, with weaker instability these storms are not likely to reach severe limits. Some small hail and gusty winds is still possible throughout much of the state during the afternoon and early evening hours.

Additional severe weather forecast updates are likely in the mid-morning hours...

Sunday, February 8, 2009

Rain & Thunderstorm!?

We will undoubtedly see our first rain of the year across the state on Monday, but a mix of winter weather may be in store for the northern third tonight. And the entire state returns to a chance of winter precipitation for Tuesday night and Wednesday as the next storm system arrives...

The state has seen temperatures in the 40s and 50s, even a few 60s the past couple of days which has allowed a considerable amount of snow melt. This snow melt combined with ice jams has created some flooding concerns across the state, with an increased chance of flooding for early this week as rain moves into the forecast. A storm system will begin to effect the state tonight as moisture moves into the lower and mid-levels. Scattered sprinkles or showers are possible tonight across the state, with the northern third seeing the risk of these showers/sprinkles freezing upon contact with the surfaces as temperatures drop below freezing. Ice accumulations is not likely, especially as any freezing rain should last only a few hours before turning into rain showers. Expect showers to become widespread by the morning hours across much of western Iowa, with these showers and thunderstorms working through the rest of the state by evening. Given the strong dynamic storm system, some instability is expected to combine with strong speed shear and low level wind shear to create the potential for a few severe thunderstorms. The main threats appear to be strong winds and maybe a few hailstones. After lows tonight ranging from 30 to 40 degrees from northeast to southwest, expect highs on Monday from the upper 40s to upper 50s from north to south. The showers and thunderstorms may continue over the northern half of the state Monday night, with lows from the mid 30s to mid 40s from northwest to southeast.

A drastic warm-up on Tuesday just ahead of the next storm system, temperatures should range from the mid 40s to mid 60s from northwest to southeast. Tuesday night lows from the mid 20s in northwest Iowa to near 40 in the southeast corner of the state. The southeast half of the state may also see some rain showers during the overnight. Light precipitation should continue on Wednesday over much of the state, with high temperatures in the mid 30s to mid 40s and falling, some mixed precipitation of rain/snow is possible. We'll see this round of precipitation move out as temperatures fall Wednesday night into the upper teens to upper 20s across the state.

A late night update is possible to address the potential for severe thunderstorms on Monday for Iowa...

Tuesday, February 3, 2009


Despite what people felt today around the state, temperatures in the upper teens at best with wind chills ranging from near zero to over 30 degrees below zero. The temperatures should be even colder tonight with lows in the single digits below zero to the negative teens in northern Iowa. The winds should be a little calmer, meaning wind chills will once again only be in the -20 to -30 range across the state tomorrow morning. High temperatures on Wednesday in the west will begin to reflect on what the state has coming for the remainder of the week, while the east stays in this quick cold spell. Highs should range from the mid teens across the northeast, to the lower 30s along the Missouri River. Overnight lows will drop into the single digits for the northeast quarter of the state, the teens northwest and southeast, and the lower 20s for areas along the Missouri and in the southwest. The entire state should see these lows come during the early nighttime hours, with steadily rising temperatures after midnight.

These rising temperatures during the overnight will set the state up for a very nice day on Thursday, Friday, and through the weekend for that matter. Southwest winds of 10-20 mph with clear skies will allow high temperatures from the mid 30s in northeast Iowa to the lower 50s in the southwest. Overnight lows on Thursday will be near 20 in the north, to near 30 in the south. The warm-up continues on Friday with even warmer temperatures, lower 40s across the northeast to the mid 50s in the southwest! The ridge responsible for these warmer temperatures does begin to move out of the state on Friday evening, which will lead to slightly cooler temperatures on Saturday. A look at the weekend forecast, and the potential for thunderstorms early next week in the next update!