Wednesday, February 28, 2007

Winter Storm (2/28 - 3/2)

2/28 Update #1

The National Weather Service has upgraded much of the advisories and watches for the state, as much of central Iowa has been now put under a Blizzard Warning. Other portions of the state are still under a Blizzard Watch and may be upgraded by tomorrow morning, otherwise at least upgraded to some type of winter storm warning/advisory. The Des Moines weather service is going to hit this one hard with many areas already in trouble with the ice and snow still hanging on trees, etc. Continued freezing rain followed by heavy snow and strong winds will produce some downright terrible conditions over the area. Below are links to the latest issuances by the NWS:

Blizzard Warning
Winter Storm Warning
Snow & Blowing Snow Advisory
Winter Weather Advisory
Blizzard Watch
Winter Storm Watch

Tuesday, February 27, 2007

Winter Storm (2/28 - 3/2)

Feb. 27 Update #1

Areas of the northern plains are already under various winter storm warnings/advisories and watches. The Dakotas/Minnesota have Winter Storm Warnings, Heavy Snow Warnings & Snow Advisories in effect already. As for Iowa, currently the northwest corner of the state has been put under a Snow Advisory as they are expecting anywhere from 3-6 inches of snow. Other portions of central and western Iowa have been put under a Winter Weather Watch, as the southern half of the watch may see 4-8 inches while north of I80 may see 6-12 inches of snow. In most areas they may also see rain/ice/sleet or any other type of mixed bag of precipitation before the snow...

Watch for these watches to be upgraded once the path and exact strength are better known. Once all of the advisories/warnings are issued I will post direct links, for now head to your local NWS office site for those texts. Also would like to point out that over half of the state of Iowa has been put under a Civil Emergency Message that was issued in joint effort by the governor, homeland security, etc.

Civil Danger Warning

Last Weekends' & Upcoming Storm

Last weekend a significant winter storm struck the northern plains, especially areas of Iowa with some locations receiving heavy snow and others significant ice. Eastern Iowa saw a mix of rain, ice and some lighter snow accumulations; Ice was the significant impact there. Western Iowa saw mainly a snow event, although some light icing was also evident. Central Iowa received both snow and ice from this event, with some areas receiving both significant ice and snows! Ames received approximately .4 inches of ice accumulation before the changeover to snow, where nearly 9 inches accumulations through the weekend. Thus, significant tree damage is noted and is still occurring as the branches are being weighted down by ice/snow. Melting is going decent, but still quite a ways to go this afternoon before the next wave of storms hits' the area possibly as early as tonight.

This next system has the potential for not only significant snows, but once again the threat for ice accumulations and thunderstorms! The southeast portion of the state is in the best chance for thunderstorms and a mainly rain event, although some minor winter accumulations are possible. The western portion of the state would likely see all winter precipitation in the form of snow. The central and northeastern corner of the state is currently the one that I think needs to pay the closest attention. The low track is expected to go right along the southeast corner of the state, thus putting these areas in the best risk for ice once again. This system is going to be another hard one to forecast though as far as what type of precipitation will occur.

Another update tomorrow with final forecast on precipitation type and snowfall totals.

Thursday, February 22, 2007

Weekend System (Forecast Update)

Models are still in good agreement and the consensus is starting to be made on what will happen over the weekend with this storm system. Some areas of Iowa have woke up to be under a Winter Storm Watch, this runs north of a line from Clinton, IA to Waterloo then to Fort Dodge, IA. The Sioux Falls NWS has yet to issue any watches, as the risk is a little less over there area. The Winter Storm Watch has been issued as these areas are under the best risk for a potential ice event Friday night into Saturday. Des Moines has stated that there is the possibility for over .25 inch of ice before the event turns completely over to snow Saturday night.

The rest of the state should see mainly rain over Friday into Saturday, with some fairly high amounts possible. Thus, flooding is also a concern for most of the state; already a major concern in Nebraska where flood statements are already being issued. The rain should come to an end by Saturday night, where the entire state should see the changeover to snow. Most of the state is in a good chance of seeing anywhere from 5-8 inches of snow with this system as it finally dissipates later Sunday. Some areas will have the possibility of even higher amounts dependent on the track of the low as well as speed. If the low slows down even slightly the total precip amounts could be significantly higher. Most of the state should keep a close eye on this system as it has some significant winter potential...

Tuesday, February 20, 2007

Weekend System (Model Update #2)

Here is another quick summary of the models from this morning, first paragraphs talking about the winter weather potential over the northern plains. The second group of paragraphs is going over the severe weather threat in the central plains with this system. Some of the areas that are stuck in between will likely see significant amounts of rain, as the moisture with this system is outstanding. Flooding is thus a concern for many of the NWS office throughout the plains as snow melt this week along with potential ice jams with heavy rain on Saturday...


As far as snowfall goes from this mornings' run I think that there will still be some good potential for snowfall. Only concern may be what type of snow it is, as even though the winds are likely to be high if the snow is heavier thanks to all of the warm air around then it may not blow around anyway. Nonetheless, you aren't going to be able to look just at the 540 line on 1000-500 mb critical thickness to figure out if it will fall as rain/snow. You are going to have to look at all of the values throughout the sounding to see if the whole column is supportive of snow.

This first looks to occur by midnight Saturday, over areas of northeastern Nebraska (North of Sioux City to Lincoln Line). This is the first area where the entire column is supportive of snow... By sunrise on Sunday it looks like eastern NE, northwest IA as well as most of MN will be supportive of snow. That is pretty much as far as the snow makes it before the low really weakens and takes off over the Great Lakes. Thus, heaviest amounts of snow are likely to be in eastern NE/western IA and then southern half of MN. At least based on the current best track of the low... Areas of central Iowa never get cold enough for snow I don't think, as the lower levels are just too warm thanks to the warm air wrapping around the low.


Definite dry line setup with such a strong dry slot working in to the low, currently this looks to be a favorable setup for anywhere from northeast Texas through eastern OK/KS and potentially further north. However, this system also seemingly is pushing the storm mode from supercells to a squall line fairly quickly and thus that is a concern I have as far as chasing goes. Storm motions will be quite quick and I'm not sure how the actual conditions will be during the day on Saturday.

Some of the things to consider will be cloud cover, how much sunlight can we actually get ahead of the system. It looks as though we will have continuous clouds throughout the day on Saturday. Also the dry slot working its' way and enhancing the dry line may also hamper development eventually, depending on its' strength and movement the dry slot will seemingly overrun the surface dryline and thus push storms even quicker or kill them off... Still a lot of information to come in as this system is still over 100 hours out. As it nears more values should be available and you can see exactly how bad of severe weather this could potentially bring. Currently you can't rule out anything, as the potential may be there for large hail, damaging winds and tornadoes with such a potent system.

Monday, February 19, 2007

Weekend System (Model Update)

This is essentially a copy of the post I made on the weather forums moments ago about the current models handling of the system coming in this weekend. The system has got the attention of not only winter weather enthusiasts, but the storm chasers & severe weather enthusiasts are also all over this one with the potential for severe weather being there as well. This is a brief update of what the models show from this morning and the afternoon runs (12z and 18z).


The morning GFS had the track from the Oklahoma panhandle Saturday morning to around the Kansas City area by Saturday evening. With intense thunderstorms likely from northeast Texas through OK/KS and MO, potentially reaching southern portions of Iowa. Otherwise wrap around precipitation and showers through the rest of Iowa, southern MN and eastern NE. The concern for snowfall sets in by midnight Saturday, with eastern Nebraska likely to be the first areas to see significant snows beginning. GFS at that time is also having some problems with convective feedback almost, if not one hell of a complex of rain/potential thunderstorms in eastern Iowa and southward. By Sunday morning this low really tightens up to nearly 983; showing significant rains now along the southern Mississippi Valley and also in the Great Lakes region. Snowfall by Sunday morning is located throughout central/western Iowa, eastern NE, southeastern SD and most of southern MN. Sunday afternoon/evening leaves lingering snow showers through the northern plains as the low moves off and weakens over the Great Lakes region. Total precipitation amounts, this of course will comes as a mixture of rain and snow over the period of the 2 days are above 1.5 inches for eastern NE, all of IA, the southeastern half of MN and various other portions of central MO (likely squall line). Areas along the IA/NE border and the IA/IL borders feature >2 inches and even >2.5 inches of total precipitation. Thus, flooding may also become a concern here with that high of totals.

The Canadian is fairly identical to the GFS at this time and the ECMWF is slightly north and east of the GFS track. Strength is fairly similar, although potentially slightly weaker than the GFS forecast.


The 18z GFS run from this afternoon is different from this morning, by Saturday evening this system is still in central KS. Thus, the GFS has slowed this system down putting areas of eastern KS/OK and northeast Texas in prime locations for severe thunderstorms. Areas of eastern NE also seeing heavy rain as they are directly north of the low. By Sunday morning the low is just over Kansas City, thus nearly 12 hrs behind the previous forecasted position. The snows do not look to be occurring except in areas of central NE and north central KS at this time, compared to previously being over eastern NE. During the day on Sunday the heaviest snows look to be occurring in MN as well as the eastern Dakotas/eastern NE. By Sunday night the low is still in central Iowa, putting some potential mix of precipitation over Iowa and areas of snow showers through MN/Dakotas and possibly eastern NE. The low is much slower in leaving, but yet leaving around the same amount of total precipitation in approx. the same areas... Although the latest run does look to have more rain than the snow.

Sunday, February 18, 2007

Nice Week Ahead!

Today features widely varied temperatures as there is a frontal boundary that is fairly stationary draped across the state. Warm south/southwest winds are featured in the southwest portion of the state. Temperatures there are in the upper 30s to mid-40s this afternoon!! As for the rest of the state, southeast winds are in place still providing warmer air, but not nearly as warm as the southwest winds. Eastern Iowa is still struggling temp-wise only being in the mid-20s while central Iowa and northwest Iowa are warmer with temperatures in the upper 20s and low 30s.
The stationary front should become a warm front and move through the area this evening/tonight and thus warm us up nicely for President's Day. Tomorrow night though will have a weak cold front push through and lower the temperatures slightly for Tuesday. For Wednesday and the remainder of the workweek though, winds will shift back to the south and warm air advection shall continue. Creating temperatures well above normal for this time of year and melting much of the snowfall that we currently have on the ground. A very nice week ahead as far as temperatures go with mainly sunny skies for the work-week.

However, by this weekend things look to change dramatically. No, I am not talking about another huge arctic burst... Instead the potential for a very strong low pressure system moving through creating the chances for significant rainfall with potential thunderstorms!! The latest forecast from Des Moines NWS puts rain chances beginning on Saturday morning with thunder also being included. This system is massive in terms of size and potential strength, providing plenty of moisture for precipitation. No need for huge details at the moment beings this system is well out of good forecast range, changes are likely between now and the end of the week. But, just to mention this system as it has quite a bit of the meteorologists/chasers talking about severe potential as well as winter potential behind the low.

Thursday, February 15, 2007

Active Pattern On Its' Way

A clipper system will once again work its' way down into the northern plains tomorrow, bring parts of the state with snow up to 3 inches. Other locations will receive a dusting to 2 inch amounts on average. Those places that do see snow will likely have travel conditions deteriorate rapidly as the wind will easily pick up the light snow and cause blowing. The snow should move in tomorrow afternoon and be gone by early Saturday morning, although some blowing could continue into the day on Saturday.

Past this system it looks as if the overall pattern over the US is likely to change, to a more of zonal flow across the plains. This flow will be interrupted over time with several low pressure systems that have been depicted in the model runs over the previous days. The first of these systems is likely to come mid-next week, although likely to affect the southern/central plains and not Iowa. The second system from this pattern is much more likely to affect the northern plains and in the past couple of runs from the GFS has been quite potent. Nonetheless, no need to get worked up yet with the system still over a week away and the notorious GFS is likely to change. Either way, a much more active pattern is likely with several waves of systems coming in and possibly producing some interesting weather...

Watch for the quick system tomorrow and then a warm-up as temperatures actually will flirt with the 40 degree mark for the southern half of the state early next week. The entire state might actually see above normal temperatures for a couple of days next week before another strong system moves in...

Wednesday, February 14, 2007

Review of Mon/Tue Snows

Well the snowstorm wasn't exactly what was forecasted, with some areas receiving much less snow than forecasted and others actually getting higher amounts. As you can read in the previous post, I did make a forecast for areas of Iowa. It is time for a review of what occurred and how well the forecast I made actually was...
Northern Iowa did not receive much snowfall thanks to the wrap-around precipitation not reaching as far north as expected and the snowfall that affected SD early Monday morning dove south instead of continuing along to the east. But, some areas of southeast Nebraska and localized areas in Iowa saw higher than expected snow amounts thanks to heavy bands that set up along the deformation zone of the low pressure system. The highest snowfall amounts in Iowa were along the south central portion of the state, although areas in Eastern Iowa also were near the 6 inch range. Below is the area average for specific areas of the state, in parentheses is my forecasted amounts for that area.

Sioux City, IA: 2-4 Inches (3-6)
Spencer, IA: 1-2 Inches (3-6)
Omaha, NE: 2-4 Inches (2-5)
Mason City, IA: 1-2 Inches (3-7)
Ames, IA: 2-3 Inches (5-8)
Des Moines, IA: 2-4 Inches (5-8)
Waterloo, IA: 0-2 Inches (4-7)
Cedar Rapids, IA: 3-6 Inches (4-7)
Dubuque, IA: 2-6 Inches (4-7)
Burlington, IA: 3-6 Inches (6-10)

Thus, I verified on only 5 out of the 10 cities, thus only 50% of my forecast was correct in a sense. Not great, but not a complete bust by most standards and not too bad considering the forecast was 24 hours out with such a complex system. Look forward to the next snow system to come in Friday and into early Saturday for the state, this system doesn't look to be too impressive. Tomorrows' update will cover this system as well as a look ahead in to the extended forecast that may become exciting!

Monday, February 12, 2007

Snowstorm (Feb. 12/13)

The snowstorm that has been forecasted, but hard to pinpoint is finally arriving in the plains. Areas of South Dakota saw fairly heavy snow this morning and into the early afternoon today, with this snow continuing to move to the east/southeast into MN/IA. Also we should watch the wrap-around moisture and thus precipitation that will come into parts of Iowa and other portions of the plains tonight. This post is forecasted mainly on Iowa as there is plenty to cover with 4 different Winter Weather Advisories/Warnings out there. The northern half of Iowa should mainly be concerned with the northern wave of snow coming out of South Dakota. The southern half will see much of the wrap around moisture from the strong low pressure system located in the southern plains. The heaviest snow is likely to fall in southeastern quarter of the state where the wrap around will be heaviest, while the lightest snows will probably fall in western Iowa. Here are the latest issuances for the state:

Snow Advisory -- Northwest Iowa (West of Hwy 4 & North of Hwy 20)
Winter Weather Advisory -- Southwest Iowa (West of Hwy 71 & South of US 20)
Winter Storm Warning -- Southeast Iowa (East of I35 & South of US 30)
Snow & Blowing Snow Advisory -- (Remainder of Iowa)

My Forecasted Snow Totals:

Sioux City, IA: 3-6 Inches
Spencer, IA: 3-6 Inches
Omaha, NE: 2-5 Inches
Mason City, IA: 3-7 Inches
Ames, IA: 5-8 Inches
Des Moines, IA: 5-8 Inches
Waterloo, IA: 4-7 Inches
Cedar Rapids, IA: 4-7 Inches
Dubuque, IA: 4-7 Inches
Burlington, IA: 6-10 Inches

Sunday, February 11, 2007

Significant Snows (Mon/Tue)

Well previous posts indicated that significant snowfall would be possible by the beginning of the week and those thoughts are likely to happen. Only problem now is exactly where these significant snows are going to occur! Lately, models from the GFS have trended slightly north and the NAM/WRF is pushing the heaviest snows significantly further north than current forecasts have it. Currently, Winter Storm Watches have been issued for extreme eastern Nebraska, southern Iowa, central Illinois and then even further east through the Ohio Valley and into the northeast.

Winter Storm Watch Texts'

Even though the NWS has issued those watches in that area, models are well north of that lineup as far as Iowa/Minnesota and South Dakota go. The snowfall forecasts then get back on track as the system enters IL and the Ohio Valley. But, no matter where the snow falls it is likely to be fairly significant with the NWS as well as models agreeing that at least 5-8 inches is likely in the heaviest band. Local amounts nearly 10 inches I think should be included as well if some type of banding can occur... Look for this heaviest snow to enter Iowa by Monday Night and quickly pile up overnight and then taper of by Tuesday. Next update likely late tonight or sometime tomorrow...

Friday, February 9, 2007

Next Snowfall (Feb. 11/12)

The next system to move through the plains is likely to be another quick moving clipper that will dive down from Canada during the day on Sunday. Areas of the northern Rockies will see snowfall tonight into Saturday, with snowfall beginning throughout Nebraska during the night on Saturday and into the day on Sunday. Areas of Iowa will likely see the snow begin late Sunday and last into Monday, by Monday night this system should be over to the IL/IN and other Midwest/Ohio valley regions...

Amounts of snow with this system are still in question, dependent on the moisture available and the snow/water ratios which currently look to be around 15:1 or so. These ratios will likely cause total accumulations to be around 3-6 inches in the hardest hit areas of Iowa, although some amounts in the 8 inch range look possible along the NE/SD border. Snowfall will likely be confined to a fairly small width, with significant drop offs as you reach the edge of the snowfall. The NAM/WRF run from this morning indicates the band of snowfall should cut across the NE/SD border and work its' way into Iowa, creating the heaviest snowfall in central/southern Iowa. The GFS run from this morning has a much different perspective, pretty much washing this system out as it enters the plains. The previous off-hour run of the GFS still indicated potentially significant snowfall in the plains and thus it is hard to agree with the 12z run of this morning. The 06z run of the GFS last night indicates the storm could be slightly south of the NAM/WRF solution, putting heaviest snows in central NE and along the IA/MO borders.

Potential looks to be there, although the morning GFS run throws a good wrench in things by washing the system out for a while. Nonetheless, the track could range slightly from north/south of the current forecast meaning areas of SD/NE/IA and MO should all watch this system for the potential of good snows during the end of the weekend and into early next week. Another update likely tomorrow afternoon...

Thursday, February 8, 2007

Nighttime Steam

Well I was testing out my camera last night, as I was attempting to figure out a problem that I was having with crap showing up in the viewfinder. I figured out the problem and of course the result is that it is being shipped back to Canon to get fixed (hopefully). I was planning on doing quite a bit with it over the next couple of weeks, but looks like that will have to be held off for a while. Maybe it will be warmer by the time I get it back?!?! Either way, last night the power plant here that is just north of my place had some great steam coming out and with a slight north wind it was coming right at me. This made it a great shot for doing some long exposures and seeing what would come of it.

Keep in mind that I don't have a tripod or remote, so I had to prop it on a tv tray stand by the window and also manually hit the shutter button, thus providing some nice movement for the camera to catch! This was the best one of the night however:

ISO 100, f/16 & 30 Second Exposure

Monday, February 5, 2007

February 6 Clipper

A quick moving system should move through the northern plains tonight into tomorrow with some quick snowfall accumulations. This storm really came into view only a couple of days ago with the confidence level in the system not being significant until earlier today. Snow amounts previously forecasted for only an inch or two have also increased throughout the day. Current forecasts indicated that some parts of Iowa may see up to 5 inches of snow by the end of the day tomorrow. The best chance for snow will be through the northwest corner of the state to the southeast corner of the state. Northeast of that line anyway, the current models are indicating a good 2-5 inches of snow to fall throughout the morning hours. Other parts of the state may see some snow, but currently does not look to be too significant.

Des Moines NWS issued a small statement about the potential for some heavy snow during the morning commute hours and thus urging people to use caution and give themselves extra time in the morning. Heavier snow amounts look to occur as the system runs into better moisture and slows down slightly. This has caused for Snow Advisories to be issued in portions of eastern Iowa through IL/IN/OH and further into the Ohio Valley. Heavy Snow Warnings were issued for parts of OH/IN/KY as well as snow may pile up quickly in that area. Keep an eye on your local forecast as conditions may rapidly change throughout the morning as snow works through the state.