Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Mon Jan 22 2024 Valid 00Z Tue Jan 23 2024 - 00Z Thu Jan 25 2024 ...Heavy rainfall and concerns for flash flooding will exist through Tuesday and Wednesday across the Lower Mississippi Valley... ...A swath of wintry weather including freezing rain and some accumulating snowfall will impact portions of the Midwest, Lower Great Lakes, and the Northeast... ...Much milder air with temperatures surging well above normal can be expected by the middle of the week for much of the eastern half of the country... Arctic air which has been well entrenched across large areas of the central and eastern U.S. over the last week will be replaced this week by much milder temperatures as a series of storm systems coming in from the Pacific Ocean crosses the Southwest and then ejects east across the southern tier of the nation. This energy will set the stage for a widespread area of unsettled weather, including the Midwest, Ohio Valley, Great Lakes, Northeast, and large areas of the South going through the middle of the week. Multiple waves of low pressure advancing along a slow-moving front across the Lower Mississippi Valley will be interacting with the resurgence of moisture and instability from the Gulf of Mexico for heavy showers and thunderstorms going through Tuesday and Wednesday. Several inches of can be expected, and there will be concerns for flash flooding including areas from the Arklatex and northwest Gulf Coast region eastward into the Mid-South. In fact, the Weather Prediction Center has issued a Moderate Risk of excessive rainfall across portions of these areas, and locally significant flash flooding may be possible given the expectation of as much as 4 to 8 inches of rain going through Wednesday. Farther to the north, the resurgence of warm air and moisture northward over the retreating cold air will foster areas of freezing rain on Tuesday and into Wednesday across areas of the Midwest, Lower Great Lakes, and the Northeast. The cold air may still be deep enough to result in some accumulating snowfall as well, and especially for areas of Lower Michigan and southwest New York where a few inches of snow will be possible. For areas where freezing rain are expected, there may be as much as a tenth of an inch of ice accretion which will result in locally hazardous travel conditions. The unsettled weather traversing the Southwest will keep temperatures across these areas relatively cool over the next couple of days, but the intrusion of Pacific air downstream across the central and eastern U.S., and southerly flow off the Gulf of Mexico, will result in considerably milder temperatures by midweek for the eastern half of the country. This will result in some temperatures by Wednesday reaching 20 degrees above average which will be a very sharp contrast to the very cold and subfreezing temperatures experienced over the last week. Orrison Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php