Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 309 PM EST Thu Dec 31 2020 Valid 00Z Fri Jan 01 2021 - 00Z Sun Jan 03 2021 ...A threat of severe weather will continue this New Years Eve across the Upper Texas Coast and expanding across portions of Louisiana, Mississippi, Alabama going into the overnight period... ...Heavy rain and a localized threat of flash flooding will exist overnight across portions of the Lower Mississippi Valley... ...Areas of snow heavy snow and icing are expected across portions of the Southern Plains and Midwest going into New Years Day, and gradually spreading into the Northeast by this weekend... ...More stormy weather to impact the Pacific Northwest with heavy lower elevation rains and heavy mountain snows for the Cascades and the Northern Rockies... A very active and stormy weather pattern will be in place across large portions of the nation as we wrap up the last several hours of 2020 and then surge into 2021. A strong storm system currently situated across the southern Plains and lower Mississippi Valley region will be driving numerous weather-related hazards over the next couple of days and into the weekend as the storm system lifts northeast through the eastern U.S. In the short-term for the remainder of this New Years Eve and the overnight period, we have a concern for severe weather from areas of the upper Texas coast to downstream areas of Louisiana, Mississippi and Alabama. The Storm Prediction Center continues to advertise an Enhanced Risk of severe weather locally with concerns for strong damaging winds and tornadoes. Meanwhile, heavy rains continue to overspread the lower Mississippi Valley region and this will advance east across areas of the Tennessee Valley and southern Appalachians on New Years Day. Some localized concerns for flash flooding, especially over the lower Mississippi Valley tonight, will be possible and the Weather Prediction Center does have a Slight Risk of excessive rainfall depicted at this time. On the northwest flank of this storm system will be an axis of heavy snowfall and some icing that will initially impact areas of the southern Plains tonight, but will then lift northeast across the middle Mississippi Valley and adjacent areas of the Midwest on New Years Day. As low pressure advances off to the northeast and impacts the eastern U.S. going into Saturday, there will likely be sufficient cold air in place for locally significant icing over parts of the central Appalachians and possible the northern Mid-Atlantic region. Snow is expected to develop across the interior of the Northeast as the system arrives on Saturday with locally heavy accumulations expected. Across the Pacific Northwest and into the northern Rockies, the next in a series of Pacific cold fronts will arrive and drive strong onshore flow and moisture transport for heavy lower elevation rainfall and heavy mountain snows. In fact portions of the Washington Cascades and the northern Rockies should see an additional 6 to 12 inches of snow going through Saturday. Overall, large portions of the nation will see relatively mild temperatures going into the start of the New Year as much the air across the nation will be Pacific in origin, and thus with a lack of Arctic air surging south from Canada over the next few days, expect generally above normal temperatures. Exceptions to this will be across parts of the southern U.S. where clouds and precipitation will help keep temperatures a bit below normal. Happy New Year!! Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php