Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 223 PM EDT Sun May 23 2021 Valid 00Z Mon May 24 2021 - 00Z Wed May 26 2021 ...Late-season snow lingering across the northern Rockies today with well above normal temperatures across the northern Plains into the Great Lakes through Tuesday... ...Scattered Thunderstorms through the Plains will produce locally heavy rains, isolated Flash Flooding and an Enhanced Risk of Severe Weather... ...Hot weather across the Northeast and Mid-Atlantic today (Sunday) will get a short break on Monday before building back on Tuesday... The mid to upper level highly amplified pattern will be starting to break down as the deep closed low across the Great Basin will lift north-northeast into south-central Canada. As such, anomalously cold air across the Northern Rockies will support another round of late season snows from Western Montana into Northwest Wyoming. A strong surface cyclone will roll out of Wyoming today pulling very warm (10-15 degrees above normal) and moist air across the northern Plains and will support an Enhanced Risk of severe weather per Storm Prediction Center with large hail and strong winds expected across across much of the northern High Plains, with best tornado prospects across northeast Colorado to Western South Dakota. This line of strong storms may produce a quick burst of heavy rain that may lead to widely scattered flooding concerns as the Weather Prediction Center highlights the similar area with a Marginal Risk of Excessive Rainfall. Slower moving cells overnight Sunday into Monday also pose a Marginal Risk of Excessive Rainfall across southeast Minnesota into much of Wisconsin; while grounds have been in drought, the quick heavy nature is not likely to soak into the ground with much running off leading to highly localized flooding concerns especially in urban settings. Monday into Tuesday, the storm will migrate into south-central Canada but the warm front will surge north across the Great Lakes and lead to high temperatures to surge into the high 80s and possible low 90s by Tuesday over the central Great Lakes, but even high 70s across far northern MN and the U.P. of Michigan too. The strong ridge over the Ohio/Tennessee Valleys into the South will support anomalously high temperatures too, with some highs into the high 90s by Tuesday across AL, GA and SC. Across the Northeast, a cold front will drop through later today and bring a break to the Northeast and coastal Mid-Atlantic with highs below average on Monday. In the crossroads between the Great Lakes/Northeast, there is a threat for repeat overnight thunderstorms that may bring excessive rainfall and potential for scattered flash flooding concerns across the Allegheny Plateau and Allegheny Mountains, where complex/rolling terrain channels water toward flooding concerns faster. Similar stormy conditions will expand into southern Mid-Atlantic and North Carolina Monday into Tuesday. The deep tropical moisture feed/atmospheric river along the southwest portion of the strong Eastern U.S. Ridge remains directed at the central Texas coast, but it appears to be reducing toward Tuesday and later in the week. Still, threat of scattered thunderstorms across saturated grounds, still poses a Slight Risk of Excessive Rainfall across the Central Texas Coast today, but a Marginal Risk remains for Monday. If there is one benefit of the deeper moisture; is the cloud cover reducing overall temperatures to near or slightly below normal across much of the Southern Plains. Gallina Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php