Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Sat Sep 21 2024 Valid 12Z Sat Sep 21 2024 - 12Z Mon Sep 23 2024 ...Threat of heavy rainfall and severe weather will be focused across the central U.S. and into Midwest for the next couple of days... ...A slow-moving coastal storm will bring another rainy day today across southeastern New England and coastal flooding during high tides for the northern Mid-Atlantic coast... ...Much below normal temperatures surge into the central High Plains on Sunday as above average temperatures shift east from the Plains into the Ohio and Mississippi Valley... Most of the active weather for the next couple of days will be focused across the central U.S. and will slowly shift east into the Midwest by Monday morning. This is in response to a vigorous upper-level low pressure system that will swing across the Southwest today and then interact with a surge of cool air down from western Canada. Thunderstorms are expected to develop quickly later today across the southern High Plains where severe weather will be possible as a cold front surges south and clashes with warm and moist air lifted northward by the upper low. By Saturday night into Sunday, the main activities will then gradually shift east across the central Plains toward the mid-Mississippi Valley as low pressure waves form along the front. Sunday into Monday morning will see the potential of heavy rain shifting farther east into the Midwest and toward the Ohio Valley. Meanwhile, colder air behind the system will change the rain into wet snow across the higher elevations of Colorado Rockies Saturday night into Sunday morning. Showers and embedded thunderstorms can also be expected farther north near/behind the cold front across the northern Plains today, into the upper Midwest tonight, followed by the upper Midwest and the Great Lakes Sunday into Monday morning. Temperatures will fall precipitously on the backside of the cold front over portions of the southern High Plains and central Plains beginning Saturday. High temperatures in the 50s will represent 15 to 30 degree departures from average for the aforementioned areas. Above average temperatures will be in place across the Midwest and Southeast this weekend as upper-level ridging extending from Mexico into Texas remains in place. Elsewhere, a slow-moving coastal storm will bring another rainy day across southeastern New England with coastal flooding during high tides for the northern Mid-Atlantic coast for today before the storm slowly moves out into the Atlantic on Sunday. Kong/Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php