Tuesday, March 31, 2009

Light Snow...

Light snow has continued to fall over much of the state this afternoon and into this evening. Here in Ames we began to have a sleet/snow mixture this afternoon, which turned into moderate snowfall through the mid-evening hours. The only places snowfall was sticking to here in Ames seemed to be cars and other very cold surfaces. Other parts of the state have also reported light to moderate snow through the evening, the only accumulations have been limited to northwest Iowa. Sioux Center had a co-op report of ~1 inch, and Sioux City reported a trace or dusting of snow. Expect some light to moderate snow to continue over some parts of the state, however, no accumulation is likely.

Lows tonight from the mid 20s in the northwest, to the lower 30s in the southeast. Highs tomorrow from near 40 in the northwest, to the mid 50s in the southeast; partly cloudy skies and westerly winds nearing 20 mph will likely lead to a chilly feeling through the day. Wednesday night lows from the 20s in the northwest to the 30s in the southeast. We'll see clearing skies for Thursday, with high temperatures in the 40s throughout the state. Thursday night lows in the mid 20s to near 30 from northwest to southeast...

Our next storm system will begin moving into the state on Friday, bringing in a rain/snow mixture for parts of the state. With the low pressure system once again forecasted to come across the state, some parts may see the risk of thunderstorms while some are seeing the chance of snow. More details on this potential storm system later...

Monday, March 30, 2009

Another Winter Storm!!!

After this weekends' winter storm that gave parts of southeast Iowa a few inches of the white stuff, and saw nearly half of the state at least see some snow flurries; we'll up for another winter storm to scrape by the state. Tonight has a strong low developing and slowly moving eastward overnight, with snow to the north and west that will give parts of northwest Iowa anywhere from 1-3" of snow by the end of Tuesday. Other parts of the state will see some light to moderate rain, maybe even a few rumbles of thunder across the central portions of the state tonight. A dry slot will also wrap around the strong low and cut-off much of the precipitation for areas south of Highway 20.

This storm system is just one of many that may move through and affect parts of the state over the next week or so...

The low track over Iowa will spare the state from much of the precip, as the heaviest bands will fall both north and west of the state. Parts of the Dakotas and into Minnesota will be looking at approximately a foot of snow or more by the end of tomorrow. Extreme northwest Iowa has the best chance of accumulation snow, with 1-3" currently forecasted. Just across into parts of SD/MN will have the shot of 3-6" of snowfall, which show how tight of a gradient this storm has; much similar to this past weekends. Light snow and rain will likely move over the northern third of the state through tomorrow, while much of the state south of there will remain dry due to the large expanse of dry air that will wrap-up around the low.

Another update with any of northwest Iowa's snow accumulations and a look ahead at the remainder of the week tomorrow night.

Wednesday, March 25, 2009

Winter Returns?

Many forecasters as well as I have been following the major storm system that is moving onto the plains this evening, and will track northeastward as we enter the end of the week and into the weekend. This storm system at the beginning of the week was centered or just south of Iowa, leaving much of the state under several inches and even feet of snow! Now as the system gets closer and we have a slightly better idea as to the track it appears that the heaviest snow may fall out into the southern plains of KS/OK/TX over the next 48 hours. Blizzard watches and other advisories are being issued for those areas, where over a foot of snow in areas of TX/OK/KS are appearing likely, not to mention the heavy snows off of the Rockies in CO! The low pressure system is still expected to move northeast once across Kansas/Oklahoma, and portions of southeast Iowa are still in-line to receive some significant snowfall amounts.

Precipitation across much of the southeast half of the state is possible, with a rain/snow mix being the going forecast. However, as the low continues to move northeast the cold air behind the low will quickly rush in and be able to turn the precipitation into snow. By that time it appears that the precipitation will be confined to an area that is southeast of a Lamoni to Oskaloosa to Dubuque line. Areas southeast of this line appear to be looking at 2-5 inches of snowfall, with the possibility of some isolated higher amounts.

Unfortunately, a very busy week at hand will have me deferring you to the local forecasters and National Weather Service for updates on this storm as it nears. For now it does appear that Friday and Saturday may be quite snowy for parts of southeast and eastern Iowa!

And if you're disappointed that you missed out on this one, it appears that we may have the potential for two more strong storms that may bring heavy rain or snow to parts of the state next week! Updates on those likely coming on Sunday!

Monday, March 23, 2009

Mar. 23 Severe Weather Update #5

The line of thunderstorms has begun to move across the state, with little in the way of severe weather being likely for the remainder of the night. Currently this line of thunderstorms is moving to the east/northeast through much of central Iowa; and should be through much of central Iowa by 1 AM. Eastern Iowa should see some thunderstorms, otherwise heavy rain-showers with the potential for some heavy rains where thunderstorms begin to train over the same path.

This will be the last severe weather update for the evening as the severe weather threat appears to be over.

Mar. 23 Severe Weather Update #4

Thunderstorms continue to roll through parts of central Iowa, with damaging winds being the main threat through the early nighttime hours. Currently, a line of severe thunderstorms is located in Dallas and Marion counties and is moving northeast. This line of thunderstorms may effect the Des Moines metro area within the next hour. Otherwise mainly general thunderstorms with strong wind gusts should move through central Iowa through Midnight tonight...

This thunderstorm has produced significant damage, just after 9:00 PM, a roof was blown off a restaurant in Adair; and a Casey's canopy has also been reported to be destroyed.

Another severe thunderstorm earlier in northwest Iowa created a significant damaging wind report from the Spencer ASOS. The report was received at 8:42 PM with a wind gust of 70 knots (81 mph)! No other reports were received from this storm as it moved north through the Iowa Great Lakes and into Jackson county Minnesota.

Another note from previous severe weather, law enforcement has confirmed that at least a brief tornado touched down approximately 3 miles south-southwest of Cumberland, IA where anhydrous-ammonia tanks were leaking.

Mar. 23 Severe Weather Update #3

Many of the thunderstorms moving across the state have weakened well below severe limits, however, one storm in southwest Iowa remains tornadic. Portions of Adams and Cass counties are under a tornado warning until 8:30 PM as a storm has showed signs of producing a tornado for the past half-hour. This storm is moving north/northeast at 55 mph and may continue to pose a threat for the next hour. The only reports received thus far are of funnel clouds that were occurring at approximately 8:00 PM. Otherwise several large hail reports (1" to 1.5") have been reported previously.

The IowaChaser radar has been zoomed in to focus on this storm as it remains the main threat for portions of Iowa this evening.

Mar. 23 Severe Weather Update #2

Severe and tornadic weather has moved into the state of Iowa, with severe thunderstorm warnings currently issued for Plymouth and Woodbury counties for the threat of penny sized hail and damaging winds; a tornado warning has been issued for Harrison county as a storm with a history of producing tornadoes has moved into the county.


At this time no damage reports have came in that are associated with any of the tornadoes that have occurred today. Additional storms should continue to move northeast into the state this evening, and expand in coverage as well as decrease in strength through the night. Additional updates on the expansion of severe weather into the state are likely tonight...

Mar. 23 Severe Weather Update #1

A Tornado Watch has been issued for portions of western Iowa, this watch will be in effect until 10:00 PM tonight for those included. For more details please see SPC Watch #55. A complex of severe and now tornadic thunderstorms has increased in coverage across eastern and northern Nebraska. These storms will continue to move north/northeast and progress eastward with the movement of a dryline/cold front that is associated with the strong low pressure system over the NE/SD borders.

These storms are likely to remain severe/tornadic through the evening and into the early nighttime hours given favorable shear values and sufficient instability. The line should move into Iowa after 6 PM, where the risk of hail and damaging winds, along with the potential for a tornado should still exist. Additional updates are likely this evening...

Sunday, March 22, 2009

Severe Weather: March 22

A strong trough, which may be closed, will move out of the inter-mountain west tonight and onto the plains states tomorrow. This trough with the combined dynamics of a mid-level jet, vorticity maxima, and other details will allow for a potentially significant severe weather event across the plains states tomorrow. This has prompted the SPC to issue a moderate risk across portions of the plains, and a slight risk for much of the state of Iowa.

An initial round of thunderstorms should develop along the strong southerly flow both at low and mid-levels tonight, these thunderstorms are likely to be elevated in nature with a marginal large hail threat through the nighttime and morning hours on Monday. These thunderstorms should initiate near the Missouri River around Midnight tonight, and move eastward with time through the night into central Iowa by sunrise. These thunderstorms may linger into eastern Iowa during the afternoon hours, however, with little in the way of severe weather.

As the mid-level jet and an increase in moisture/temperatures ahead of the cold front move into the central plains, a stronger threat of severe weather is likely to develop during the afternoon hours on Monday. Thunderstorms over SD/NE will continue to move eastward during the day, entering eastern SD/NE by afternoon. With the potential for instability and strong shear, both large hail and damaging winds, along with a few tornadoes may be possible if storms can remain discrete. As the cold front begins to sweep eastward during the evening and overnight hours, these storms should become more linear and move into Iowa. As they move quickly into the state during the evening/overnight hours on Monday into Tuesday they may pose both a wind and hail threat for the state. Additional updates are possible tomorrow for the severe weather threat for Iowa...

Tuesday, March 17, 2009

Wonderful Weather Continues...

High temperatures over the past couple of days have been well above normal, and prompted many people to get outside and enjoy it! Today is likely to be the last day with temperatures well above normal, as a cold front will sweep over the state tonight and into early tomorrow. No significant chances of rain showers are in the forecast with the passage of the front, just a cool down of 10-20 degrees of those high from today and yesterday. That still means temperatures in the 40s and 50s throughout the state, which is still right around normal for this time of year.

Highs today should range from the mid 60s to the mid 70s from north to south across the state, with warm southerly winds and clear skies. The cold front begins to make its' way into western Iowa tonight; with a slight chance of a few showers or otherwise partly cloudy skies with lows in the 30s across the northwest and the 40s over the remainder of the state. This front will continue to move across the state on Wednesday, with a chance of showers and otherwise cloudy skies across much of the state. High temperatures should range from the mid 50s to near 60 from northwest to southeast. The skies will clear out for Wednesday night, with low temperatures in the upper 20s across the north to the mid 30s over the south.

The remainder of the work week will have high temperatures in the 50s on Thursday, and then the 50s and a few 60s southwest on Friday. Low temperatures in the upper 20s to mid 30s from east to west on Thursday night will warm up by Friday night when lows should range from the mid 30s to the lower 40s from east to west. We'll bring in the chance at a few showers for the state for both the beginning and the end of the weekend... Enjoy the mild week ahead...

Friday, March 13, 2009

Warming Up!

Nice southerly winds and clear skies will give way to warming temperatures throughout the weekend and into early next week. Even though a cool-down will come during next week, temperatures still look to remain above normal through the remainder of the week. Current temperatures for this Friday afternoon range from the lower 30s to upper 30s from north to south; although a few 40s are creeping into the western part of the state. Expect a few more degrees of warming as skies clear, with highs into the upper 30s to upper 40s by the time we begin to fall back down in the late afternoon hours.

Lows tonight should be in the low to mid 20s; with highs tomorrow into the upper 40s to mid 50s from northeast to southwest across the state. Saturday and Sunday night lows will be in the 30s throughout the state, with Sunday being just a few degrees warmer. Sunday temperatures will increase another few degrees, into the lower to mid 50s across the state. Monday temperatures will be even higher, from near 60 to the upper 60s from northeast to southwest across the state. Tuesday high temperatures will range from the upper 50s to mid 60s; and then into the upper 40s to upper 50s come Wednesday... More on next weeks' temperatures on Monday! Enjoy the weekend...

Monday, March 9, 2009

Winter Storm: Mar 10

Although only a small portion of the state will see winter precipitation, this will still be one of the main highlights of our storm system that is currently effecting the state. While thunderstorms and showers should dominate the forecast for all but northwest Iowa, this will create the potential for additional flooding and overall saturated conditions. Storm total precipitation should range from a few tenths across the diagonal of the state to upwards of a half inch across southeast Iowa. These heavier amounts are likely to come from isolated thunderstorms, some of which over extreme southeast Iowa may be able to reach severe limits with strong winds and large hail. Across northwest Iowa, a mixture of sleet and snow seems likely, along with some freezing rain during the early hours of the event. Snow accumulations should generally only be 1-3 inches for areas that are currently under a Winter Weather Advisory; other parts of the state bordering this advisory will see snowfall but generally no accumulations.

The other part of this storm system will be the cold air funneling in behind the low pressure system, and the strong winds that will move in tomorrow afternoon and overnight. Highs tomorrow will range from near 20 in northwest Iowa as they remain to in the cold air; while southwest Iowa will attempt to reach the 60s in the warm sector of the low pressure system. The cold air moves through the entire state by Tuesday night, bringing lows down into the single digits across northwest Iowa and the upper teens across southeast Iowa. Highs on Wednesday will only reach the teens across the northwest, and the lower 30s across the southeast. We'll look to slowly warm-up through the week, and continue to warm into the weekend.

Sunday, March 8, 2009

Severe & Winter Storm: Mar. 7-8 Update #1

While the southern two-thirds of the state continues to see rain and thunderstorms this morning, precipitation is also beginning to move into parts of northwest and northern Iowa where they are expecting winter-type precipitation through this afternoon. While roadways are wet throughout much of the state, there are now reports across northwest Iowa indicating that roadways are beginning to become covered in snow/sleet and are freezing over.

Precipitation is expected to continue across the entire state through the early afternoon hours, with mainly rain expected south of a Onawa to Fort Dodge to Mason City to LaCrosse, WI line. North of that line, a mixture of freezing rain, sleet, and snow is expected. The heaviest snow amounts are expected across northwest Iowa, where 1-3 inches of accumulation may be seen with a mixture of sleet. Other parts of northern and western Iowa are likely to see a combination of precip-types, and a total of 1-2 inches of accumulation by the end of the afternoon.

Expect the low pressure system to move into Illinois by this afternoon, which will begin to pull the precip out of the state. Currently it looks like by mid-afternoon all but the northeast quarter of the state will become dry; northeast Iowa should see an end to the precip by the end of the evening.

Friday, March 6, 2009

Severe & Winter Storm: Mar. 7-8

As we head into the weekend, showers and thunderstorms are entering portions of western and southern Iowa. These showers and thunderstorms will likely continue across the state throughout the nighttime hours, and through the afternoon tomorrow. Total rainfall amounts may be quite heavy, greater than an inch in most areas, with up to 2-3 inches possible across parts of the state. Due to this heavy amount of rain this early in the spring, the Davenport NWS has issued a flash flood watch across its' entire area. The Des Moines NWS did state that rises in rivers are expected, although they expect it to remain with the banks for most, if not all, rivers.

Overnight tonight, and potentially late Saturday night, there is the potential for some severe thunderstorms. Overnight tonight, the main threat with any thunderstorm will be the potential for marginally severe hail. This has already occurred over northern Missouri, and will not be surprised to see a few warnings across the southern half of the state for some 3/4" to 1" diameter hail. Thunderstorms on Saturday are expected to initiate over Kansas, where clear skies or at least more favorable conditions will give way to new development. This may congeal into a larger complex of storms that will move northeast into the overnight. This complex of storms may reach the far southern counties in the state, giving them the chance at some additional large hail and/or damaging winds.

Another complex situation occurs beginning Saturday night, as cold air enters the state behind the exiting low pressure system that will be over eastern Iowa. This cold air both at the surface and aloft will give way to frozen precipitation over much of northern Iowa. Currently the NWS in Sioux Falls has issued a Winter Weather Advisory for portions of northwest Iowa where a combination of freezing rain and accumulation snow is likely to occur Saturday night and into early Sunday. Some portions of northern Iowa have the potential for 3-6 inches of snow according to the latest models; with some higher amounts even being forecasted in both the NAM and GFS. Expect a combination of freezing rain and snow on Saturday night anywhere north of Highway 20; with accumulations of snow being likely. The amounts are going to be hard to pinpoint, given that the speed and amount of cold air will determine how quickly in changes over and thus how much snow places will see.

Be sure to check out the latest radar image on the Iowa Chaser Homepage: http://www.iowachaser.com

Thursday, March 5, 2009

Record Warmth!

With the southerly flow and clear skies, temperatures today soared well above what forecasts were predicting. This is one case where a missed forecast won't get the public riled up... Temperatures across the state ranged from the 50s across northwest Iowa, into the upper 60s across much of northeast Iowa; and then near 70 or well into the 70s for much of the southern portion of the state. Although an official statement regarding any records will likely be issued tonight, it appears safe to assume that several cities have at least tied if not broke their record high for today!

Hope everyone got out to enjoy it! Tomorrow looks to be a little cooler, and with plenty of rain, thunderstorms, and potentially frozen precipitation for some parts of the state over the weekend. Additional details on the weekend storm will be posted in tomorrows update...

Wednesday, March 4, 2009

Spring Feel...

For the remainder of the work week the state will be in a spring-like feeling, with temperatures well above normal under clear skies and strong southerly flow. The portions of western and northern Iowa that previously had snow-cover saw it all melt away today under the clear skies and temperatures into the 40s. The portions of the state without snow-cover saw temperatures into the 50s. This warming trend will continue for tomorrow and steady-off for Friday, just before our next system moves in for the weekend.

Temperatures on Thursday will range from the mid 50s in the north to the mid 60s in the south. Clear skies and strong southerly winds of 10-20 mph will keep it feeling just slightly cooler than that. Low temperatures on Thursday night will be from near 30 in the northwest corner, to the mid 40s in the southeast. Friday will once again be above normal, partly cloudy skies will allow plenty of sunshine. However, a high pressure system located over the state will keep the strong southerly flow away from the state and thus slightly cooler. Highs in the lower 50s to lower 60s from north to south are expected. Friday night lows will range from near 30 in northwest Iowa to the mid 40s in southern Iowa once again.

A low pressure system should begin to effect the state on Saturday, with a warm front moving into the state with warm and moist conditions just south. Thunderstorms look to be a distinct possibility across southern Iowa, with general showers across the northern half. Some previous forecasts had mentioned the possibility for a rain/snow mix during the height of precipitation. Currently it looks to remain too warm until Saturday night for any frozen precip, but forecasters are going to be watching closely to see how the forecast evolves.