Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 256 AM EST Wed Feb 12 2020 Valid 12Z Wed Feb 12 2020 - 12Z Fri Feb 14 2020 ...There is a Moderate Risk of excessive rainfall from northern Mississippi to central Kentucky through Thursday morning. A broad area from northeast Tee Upper Tennessee Valley and Cumberland Plateau for Wednesday. A Slight Risk remains today (Tuesday) from eastern Texas, northern Louisiana, southern Arkansas expanding into the Upper Ohio Valley... ...A Slight Risk of Severe Weather has been issued by the Storm Prediction Center (SPC) for portions of the central Gulf states and the Tennessee Valley... ...Light-to-moderate snow is possible with some mixed freezing rain will be possible across central IND-OH, northern PA into NY and West-Central New England though Wednesday night... Much of the Gulf states and areas north into the Tennessee Valley and Southern/Central Appalachians are 300 to 600% of normal for received rainfall in the past 1 to 2 weeks. With pooled Gulf moisture interacting with a slow moving front from the western Gulf Coast to the Mid-Atlantic, moderate to heavy rain will persist across the South. A surface low pressure is expected to develop today (Wednesday) and deepen across the eastern coast of Texas into western Tennessee. By Thursday morning, the surface low will have quickly progressed into the Upper Ohio Valley/Allegheny Plateau with the cold front pressing through the Appalachian mountains. WPC has a Moderate Risk for excessive rainfall in effect from northeast Mississippi to south-central Kentucky through Thursday. However, ample rain across the Gulf states into the Tennessee Valley and Appalachian region will persist through the end of the week. In addition to the flooding threat, the Storm Prediction Center has highlighted much of Mississippi to eastern Tennessee as having a Slight Risk for strong to severe thunderstorm development. An Arctic airmass will surge south through the Northern Plains and Upper Mississippi Valley, allowing temperatures to fall 10 to 20 degrees below average in the wake of the frontal passage. The combination of the moisture drawn out of the Gulf ahead of the front and approaching colder air from the north will support the threat for light to occasionally moderate snows north of the front in from Indian to New York, with some mixing and potential for freezing rain conditions. Temperatures behind the Arctic cold front will expand across the Upper Midwest and into the Western Great Lakes by the end of the forecast period (Thursday night) with similar 10-20 degree below average values expected. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php