Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 311 PM EST Mon Nov 22 2021 Valid 00Z Tue Nov 23 2021 - 00Z Thu Nov 25 2021 ...Holiday travelers thankful as Thanksgiving week kicks off on a tranquil note across much of the Lower 48... ...Wet and snowy conditions in the Northwest; Lake effect snow showers in the Great Lakes... ...Scattered rainfall and thunderstorms begin over Southern Plains and Mississippi Valley Wednesday night... ...Chilly temperatures in the East, warmer trend in the Heartland; Critical fire weather areas in the central High Plains and Southern California... A relatively quiet start to Thanksgiving week will give way to an active period for portions of the Southern Plains and Mississippi Valley by midweek. The departures of a pair of cold fronts in the East will usher in a period of cooler weather across the eastern third of the country over the next couple of days as high pressure settles over the region. A shift to northwesterly winds across the Great Lakes will generate Lake effect snow showers through Tuesday afternoon before winds shift again ahead of an approaching system. First freeze potential exists over parts of the interior Southeast tonight and Tuesday night as temperatures are expected to drop to between 15-20 degrees below average in some places, which may lead to impacts to sensitive soils/crops. Our main weather driver of the week will be a shortwave trough, which is currently impacting the Pacific Northwest and the sensible weather impacts it causes across the Southern Plains and Mississippi Valley on Thanksgiving. Rain and snow showers are forecast for the low elevations and mountains of the Northwest respectively through Tuesday night. Several inches to isolated amounts well over a foot of snow are expected for the Northwest mountain ranges with marginal rainfall amounts likely for lower elevations. The upper trough will dig into the Southwest and northern Mexico over the next couple days. High temperatures will likely be between 15-20 degrees above average across portions of the Great Plains and Upper Midwest as a result. Critical Fire weather outlooks were issued for portions of the Central Plains due to the warm up, as drier air and windy conditions settle-in over the next two days. The amplifying pattern will lead to the development of scattered rain showers and thunderstorms across the Southern Plains and Mississippi Valley by Wednesday afternoon/evening. There's a potential for heavy rainfall to impact portions of southeast Texas on Thanksgiving day as the, now very amplified, upper trough over northern Mexico taps into a rich repository of moisture from the Gulf of Mexico and spreads it along the surface cold front extending from eastern Texas into the Lower/Middle Mississippi Valley and Midwest. Kebede/Mullinax Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php