This post was written by Schnack on June 20, 2012
The front continues to track east across central Iowa. Ahead of the front it is still very warm and humid. Clouds have been increasing across eastern Iowa in the last couple of hours. The sky is cloudy along and behind the cold front. The clouds are starting to clear in far NW Iowa. Once the front crosses your location the wind direction will shift from the SW to the N/NW. The temperatures will also drop into the 60s with the rain cooled air.
The next image is the radar. Right along and just behind the front is where the thunderstorms are located. Behind that…rain showers extended about 75 miles west of the front. There have been a few showers developing in parts of eastern Iowa ahead of the line of storms. Some of the storms may produce some gusty winds up to 40 mph with heavy downpours. The threat for severe weather is low and as the sun goes down the severe threat will end. The storms will weaken as they track east into eastern Iowa.
Posted under Update
Tonight: Mostly cloudy with a 70% chance of showers/storms. Low: 61-64. Wind: NW 5-15 mph.
Thursday: Mostly sunny, cooler and less humid. High: 79-83. Wind: NW 10-15 mph.
Thursday Night: Mostly clear. Low: 57-60. Wind: NW 5 mph.
Friday: Mostly sunny. High: low 80s.
Saturday: Partly cloudy. High: low-mid 80s.
Sunday: Partly cloudy with a 20% chance of showers/storms. High: low 80s.
Monday: Mostly sunny. High: low 80s.
Tuesday: Mostly sunny. High: low 80s.
Wednesday: Mostly sunny. High: low-mid 80s.
A cold front in northwest Iowa this afternoon is producing a few showers/storms. The map below shows the position of the cold front.
The front is forecast to push east through eastern Iowa tonight. There will be a chance of showers/storms tonight until about 3 or 4 AM. After that…the clouds will clear. Any rain that falls with the front will be about 0.50” or less. There is a better chance of rain in our NW counties than our SE counties. The map below is the rain forecast from this evening to Thursday evening.
As the front crosses the state, the SPC has part of our area in a slight risk. If any storms become severe the primary threat would be high wind and hail. The chance of severe weather is low. Here is the severe weather outlook for tonight:
The front will be east of Iowa by Thursday. High pressure will slowly cross the Midwest Thursday and Friday. Expect plenty of sunshine, cooler temperatures, lower humidity and a lighter wind. There is chance of showers/storms to develop over Nebraska Saturday and right now it looks like they would track south of viewing area. For this reason I will keep Saturday dry with more clouds.
A weak area of low pressure will develop southwest of Iowa and track southeast. There will be a few more clouds around Sunday with just a slight chance of a shower/storm. I am going to keep this rain chance in right now but the way the models have been trending…the high from Canada will push this low far enough south we stay dry. The map below shows the position of the low Sunday morning.
Speaking of the high in Canada in the previous paragraph…that high is large and will stretch south across the Midwest and Great Lakes area through the first half of next week keeping our weather dry. During this time the conditions will be more pleasant.
Posted under Forecast Discussion
MESOSCALE DISCUSSION 1234
NWS STORM PREDICTION CENTER NORMAN OK
0210 PM CDT WED JUN 20 2012
AREAS AFFECTED…WRN UPPER MI/NRN AND WRN WI/SERN MN/NRN IA
CONCERNING…SEVERE POTENTIAL…WATCH POSSIBLE
VALID 201910Z – 202045Z
PROBABILITY OF WATCH ISSUANCE…40 PERCENT
SUMMARY…SLOWLY INCREASING CONVECTION AHEAD OF THE SURFACE COLD FRONT — AND ASSOCIATED POTENTIAL FOR LOCALLY DAMAGING WINDS/HAIL – MAY REQUIRE WW ISSUANCE THIS AFTERNOON.
Click here for the rest of the technical discussion from SPC.
1988: A very hot and dry summer intensified in late June with about half of the observing stations in Iowa reporting triple digit heat on the 20th, including Dubuque which incredibly reached 100 F for the first time since 1941. The highest reported temperatures included 102 F at Carroll, Charles City, Sioux City, and Waterloo, and 104 F at Jefferson and Red Oak. Remarkably temperatures would rise even further the following day.
1974: Just two days after an F4 tornado produced fatalities in central Iowa another killer tornado struck northern Clinton County, resulting in one death and 20 injuries. Widespread severe weather spread from northern into eastern Iowa with large hail, wind gusts to 75 to 90 mph, and flash flooding occurring from Kossuth, Winnebago, and Hancock counties over to Allamakee, Dubuque, Cedar, and Lee counties.
1908: A severe thunderstorm cut a path across far northeastern Iowa producing heavy rain, strong winds, and very large hail in a damage swath around 15 miles wide extending from Cresco to McGregor. Many animals were drowned or killed by the hail and in some locations the stones were large enough to break the siding on houses. At Decorah an observer noted that all crops were completely destroyed within the hail swath and that “the foliage was entirely stripped from all trees and plants”. Several barns and outbuildings were also blown down by the strong straight-line winds. At South McGregor a severe flash flood washed logs from the lumber yards and “any loose objects that would float” into the Mississippi River and deposited 3 to 4 feet of mud in many businesses and homes.
|This Day in National/World Weather History …|
Posted under Weather History