Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Fri May 20 2016 Valid 00Z Sat May 21 2016 - 00Z Mon May 23 2016 ...Soaking rains expected across the Mid-Atlantic and Southeast... ...Showers and thunderstorms will continue to move across the Great Basin and Pacific Northwest... The surface front associated with the heavy rainfall and severe weather over Texas and Louisiana on Wednesday is still draped across the Gulf Coast states--with most of the heavier rainfall located in the Gulf of Mexico. There is also moderate rain falling in the Tennessee Valley. This bulk of precipitation will continue to progress to the northeast and spread across the Ohio Valley and Mid-Atlantic overnight and into Saturday. The Southeast and the northern half of Florida can also expected rain--albeit lighter amounts throughout the day on Saturday. A surface low associated with the heavier rainfall will move across the Mid-Atlantic during Saturday afternoon and is expected to exit the East Coast in the evening. Most of the rainfall will taper off with the low's departure, however some lighter showers will linger on Sunday. Thus, for the Mid-Atlantic and Northeast, most of the weekend can expect less spring-like sunshine and more of the springtime showers. A large upper level low is currently moving very slowly southward across the Pacific Northwest and will continue to advance toward the Desert Southwest through Saturday and into Sunday. Because of this slow movement, the surface front will also not progress very much over the Great Basin through Friday night and Saturday. Consequently, most of the precipitation will be confined to the Pacific Northwest and northern Rockies through the first half of the weekend. However, by Sunday, the upper level low weakens and kicks some energy out into the northern and central Plains. This will help drive the surface front across this region, bringing with it showers and thunderstorms. Farther south in the southern Plains, convective activity can also be expected as strong low level moisture streams across this area from the Gulf ahead of the approaching cold front. In fact, storms across all of the plains could be severe--the Storm Prediction Center has a slight risk accounting for this. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php