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

Warmer!

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.