Corn Belt Weather: Cool, Damp Now, Warm Air on the Way
Portions of the Midwest are off to another wet and soggy start this morning as a wave of low pressure develops along the the downstream portion of a large upper-level trough of low pressure.
This wave of low pressure will spread steady rainfall throughout the central and eastern Corn Belt this afternoon, with rainfall totals through tomorrow morning forecast to reach 1 inch with 80% coverage from southeast Illinois eastward through the Ohio Valley. Ample cloud cover in these areas will keep temperatures well below normal from Indiana west into Illinois where highs will be in the 50s and 60s.
Across Ohio, temperatures will be warmer ahead of an approaching frontal boundary with 60s and 70s possible. Farther west across western portions of the Corn Belt, today's weather will be considerably drier, although daytime highs will only be in the 50s and 60s.
Tomorrow, more clouds than sun along with scattered showers will be the main picture across the Midwest with chilly temperatures in the 50s and lower 60s. Shower chances will linger across much of the Midwestern U.S. into Friday, putting a damper on fieldwork and planting. As we head into Saturday, warmer weather begins approaching the western Corn Belt as an upper-level ridge begins approaching from the Plains. Drier conditions will also overspread the western Corn Belt with only isolated rain chances to the east.
By this time, four-day rainfall totals will range from 0.1 to 0.5 inch from Nebraska eastwards into western Ilinois, with 0.5 to 1.0 inch across eastern Illinois into northwest Indiana with 1 to 2 inches through the remainder of the Ohio Valley. Sunday, upper-level ridging will establish itself across the central U.S., with a classic omega-blocking pattern setting up into early next week. This may provide warmer and drier weather conditions for the Corn Belt heading into early next week, although a slow moving frontal boundary may spoil any extended attempt at a rain-free period.
Noteworthy is the agreement between our models through this time frame, with the GFS and ECMWF showing very similar surface and upper-level features heading into next week. This increases confidence in the forecast through this time frame. Also, the past several runs of both models continue to indicate a cut-off upper-level trough digging into the western U.S.
If the trough axis ends up as far west as our computer models are currently advertising, rainfall chances across the southern Plains will increase later in the six- to 10-day time frame with above-normal rainfall possible.
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