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Midwestern temperatures moderating
Temperatures across the country this morning are in the teens and 20s from Nebraska northward, with 30s, 40s, and even a few 50 degree readings across the Midwest. A weak cold front is currently crossing the Midwest, with the associated wind shift oriented in a NNE-SSW line across eastern Iowa and western Wiconsin.
Prior to the passage of this frontal boundary, a unique situation known as a heat burst occurred over Des Moines where temperatures at 2 a.m. rose sharply from 39 to 49 degrees. Examining the vertical temperature profile, it appears a pocket of very warm air (48F to 50F) existed a mere 400 feet off the ground, and likely mixed to the surface as the cold front stirred up the boundary layer.
Shifting away from dynamics . . . temperatures across the Midwest this afternoon will reach well into the 40s ahead of the frontal boundary for much of Indiana, Ohio, and southern Illinois, with some readings potentially reaching the 50s. Cooler temperatures will exist behind the front across Iowa and Minnesota with 20s and 30s prevalent. Late this afternoon and into the overnight hours, Alberta Clipper #1 will cross from NW to SE through the Midwest, reaching NW Iowa by 6 p.m., and northwestern Illinois shortly after midnight.
Little if any precipitation is expected to accompany this clipper, although a heavier axis of precipitation will fall across south/central Minnesota with 2 to 3 inches of snowfall possible here. This clipper will bring a few light sprinkles to the Ohio Valley Tuesday afternoon, with some light snow possible across extreme N Indiana and N Illinois. Winds will also be quite gusty tomorrow especially across the western Midwest as 45-mph winds only 2,000 feet off the surface mix down to the ground, resulting in gusts from 30 to 40 mph.
Wednesday will feature lighter winds and dry weather for the western Midwest with at least partial sunshine. Across the Ohio Valley, a strong upper-trough will result in more cloud cover with flurries and even a few snowshowers possible. Temperatures will be in the teens north, to upper 20s/lower 30s south. Wednesday night clipper # 2 crosses the northern Midwest, once again with little in the way of precipitation, despite a few spotty snowshowers across the northern half of Iowa and Illinois. These light snowshowers will cross through the northern Ohio Valley Thursday morning.
Temperatures Thursday will warm into the 20s and 30s before another cold front moves through overnight into Friday morning, resulting in temperatures struggling to reach the teens and 20s across most of the Corn Belt. Some single-digit highs may occur across northeast Iowa and northwest Illinois north into western Wisconsin and Minnesota. No damage to hard or soft winter wheat is expected. These cold temperatures will then reside across the northern Ohio valley Saturday with Sunday the 19th being the coldest for the Northeast. It then appears a warmer pattern will take hold, potentially lasting through the 22nd.
Looking at the upper-level pattern depicted by the latest long-range models, there is a trend for cooler-than-normal weather for the northeastern third of the nation during the 11- to 15-day time frame. In fact, the European model is coldest with a noticeably cooler trend from 00z last night when compared with yesterday's 12z run. Both the European and GFS try to reestablish ridging across the Gulf of Alaska with a ridge across the North Atlantic. This would tend to favor cooler than normal weather for the Ohio Valley and New England.
Of greater certainty is the long-term dry trend in store for the central/western Midwest and central/southern Plains. Although we are still several months away from the planting season, spring rainfall will be increasingly important in mitigating dry soil mositure across Iowa and western Illinois. Across the eastern Midwest, soil mositure is plentiful.
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