Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 313 AM EST Tue Dec 06 2022 Valid 12Z Tue Dec 06 2022 - 12Z Thu Dec 08 2022 ...Heavy rain and isolated flash flooding potentials shift westward from the Tennessee Valley today to the central Plains later on Wednesday into Thursday... ...Accumulating snows across the northern Plains and through portions of the northern and central Rockies... ...Widespread much above average temperatures across the southern and eastern U.S. in stark contrast with arctic air across the northern Plains... A slow-moving frontal boundary will continue to be the focus of active weather across the south-central portion of the country during the next couple of days. The first episode of heavy rain has already been impacting areas from the interior Deep South eastward into northern Georgia and portions of Tennessee early this morning. The moisture will be carried rapidly northeast across the interior eastern U.S. today and into New England by tonight. The associated rainfall is expected to be more scattered in nature. However, parts of the Appalachians, as well as northern Mid-Atlantic into New England will have the best chance of seeing periods of moderate rainfall later today into Wednesday as a low pressure wave forms along the front. In the mean time, a jet stream arriving from the eastern Pacific will begin to interact with the front across the southern Plains. This interaction will bring a second round of heavy rain from the southern Plains eastward across the lower Mississippi Valley and into the Tennessee Valley starting on Wednesday. Portions of these regions have had above average precipitation over the past few weeks, resulting in increasingly saturated soils, with heavy rain potential on these saturated soils increasing the flash flood threat. By Wednesday night into Thursday morning, a low pressure wave is forecast to develop over the southern High Plains along the front. This system is forecast to shift the heavy rain threat slightly northward across Oklahoma toward the Missouri-Arkansas border Wednesday night/early Thursday. In addition, temperatures will be cold enough to support wintry precipitation across the central Plains. The overall pattern supporting the wet weather from the southern Plains into the Northeast will also support much above average temperatures over the next few days over the central to southern Plains eastward into the East Coast. A few record high minimum temperatures are forecast this morning across the lower Mississippi Valley, with a much more expansive area of potentially record high minimum temperature possible Wednesday morning across portions of the southern Plains, lower Mississippi Valley, Tennessee Valley, Mid-Atlantic and Northeast. Below average temperatures over the next few days are expected across areas west of the Rockies and across the northern Plains. The greatest below average temperatures are expected across the northern Plains where arctic air will keep temperatures 15-20 degrees below average from eastern Montana, across the Dakotas and into Minnesota. However, record cold temperatures are not expected across this region over the next two days. This area will also see the threat of periods of accumulating snows over the next two days. Amounts are not expected to be very heavy, generally in the 1 to 4 inch range. The heaviest snows over the next few days expected through the Rockies of Colorado, northwest Montana and northern Idaho where totals in excess of a foot are possible. Kong/Oravec Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php