Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 338 PM EST Tue Jan 23 2024 Valid 00Z Wed Jan 24 2024 - 00Z Fri Jan 26 2024 ...Heavy rainfall and concerns for flash flooding will exist through Thursday morning across the Lower Mississippi Valley... ...A swath of 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 through the middle of the week for much of the eastern half of the country... A low pressure system in the Lower Mississippi Valley supported by an upper trough digging into the Southwest will continue to produce heavy to excessive rainfall and flash flooding concerns across portions of the Southern Plains, Gulf Coast, Lower Mississippi Valley and Southeast through midweek. Tonight, repeat rounds of convection will produce heavy rainfall along a stationary front over parts of the ArkLaTex down to the Texas/Louisiana coast. A Moderate Risk of Excessive Rainfall is in effect for areas including eastern Texas, southern Arkansas and northwestern Louisiana for this evening. The final storm of the evening is forecast to organize on Wednesday morning and generate additional flash flooding impacts over the Central Gulf Coast into the Lower Mississippi Valley. Another Moderate Risk of Excessive Rainfall is in effect over parts of central Louisiana, central Mississippi and northwestern Alabama where this organized complex of storms will produce high rainfall rates and potential training within a rich moisture environment. A continuous fetch of moisture will stream into the Central Gulf Coast from Wednesday night through Thursday night, leading to more flash flooding concerns from Louisiana to southwest Virginia/southeast Kentucky where a broad Slight Risk of Excessive Rainfall is in effect. Elsewhere, a deep low pressure system will spread Pacific moisture across much of the Northwest leading to coastal rainfall and mountain snow for much of the Pacific Northwest and northern California beginning tonight. To the north of this system warm air advection into the Midwest and Great Lakes will promote freezing rain and snow showers for those areas tonight into Wednesday before spreading into the Northeast on Wednesday afternoon/evening. Light accumulations are expected. The aforementioned warm air advection caused by the emerging storm system in the Gulf Coast/Southeast and the deepening upper low over the Southwest powering it will promote a significant warming trend across the Midwest and East Coast through the end of the work week. There will be a lot of snow melt across the Midwest, Mid-Atlantic and Northeast this week with highs well into the 40s and 50s and lows 40-50 degrees above average in many places. These anomalous low temperatures will likely break many records, particularly east of the Mississippi Wednesday and Thursday night. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php