Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 335 PM EDT Thu Oct 08 2015 Valid 00Z Fri Oct 09 2015 - 00Z Sun Oct 11 2015 ...Showers and thunderstorms will begin to wind down across West Texas Thursday night.. ...Stormy weather expected across the Pacific Northwest... ...Heavy rain and flash flooding possible for the Southeast... An upper level low situated over northern Mexico will begin to retrograde back to the Pacific tonight and into Friday as an upper ridge builds across the southwestern portions of the U.S. In the meantime, this low will continue to stream warm, moist air from the Gulf of Mexico across West Texas and New Mexico. Showers and thunderstorms, as a result, will continue to fire off especially east of the Big Bend region through Friday. Given that the past few days have been quite wet for this area, flash flooding will still be a concern through Friday morning. By Friday night, the majority of the precipitation will fall across northern Mexico just south of the Rio Grande as the upper low moves westward. Mostly dry conditions will settle across west and south Texas by Saturday, with measurable precipitation falling across the higher elevations of Mexico. Tropical moisture combined with upper level disturbances will yield to a wet pattern during the short term period for the Pacific Northwest. Rain will be mostly confined across coastal portions of British Columbia and Washington state on Thursday night and into early Friday. However, as the upper level trough driving the disturbances dips further south on Friday and into Saturday, the axis of precipitation will shift in response. Showers will begin to ramp up across coastal Washington and Oregon on Friday evening with heavier amounts falling across the Cascades with the heaviest amount of precipitation occurring on Saturday. Amounts over 3 inches of rainfall could occur along the Cascades and may produce flash flooding. An upper level low driving a front from the Great Lakes to the Plains will bring showers and thunderstorms spanning across New England to Arkansas. New England especially could receive heavy rainfall, but given the fast moving nature of this system flash flooding is not a primary concern. The surface front associated with the upper level features will move off the East Coast by Friday night. However, on Saturday the cold front along with the upper level trough will lag behind in the Southeast. The southern and central Appalachians will receive the most amount of precipitation through Saturday morning. Showers and thunderstorms will then begin to spread across the Carolinas during the day. Although a significantly less amount of rain is expected to fall across the Carolinas compared to last weekend, any extra rainfall will exacerbate these regions and could produce flash flooding. Consequently, WPC has a slight risk over mainly South Carolina to account for this threat. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php