Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 432 AM EDT Sat Apr 19 2014 Valid 12Z Sat Apr 19 2014 - 12Z Mon Apr 21 2014 ...Heavy rainfall will be possible across the coastal Carolinas throughout the weekend... ...A threat for severe weather looms across areas of West Texas on Sunday... A split flow regime will continue across the country with both streams being fairly active during the period. A pair of systems in the southern branch of the jet are forecast to be active precipitation producers this weekend. The lead upper trof currently spreading moderate to heavy rainfall to the Southeastern U.S. is expected to remain a slow mover as the closed low wobbles slowly toward the east. The approaching system should continue to have access to plenty of moisture off the Gulf of Mexico and subtropical Atlantic waters. Ample vertical lift along the slow moving cold front combined with dynamics aloft with the upper low will continue to aid in the production of heavy rainfall throughout the weekend. The WPC precipitation forecast suggests amounts may approach the 2 to 4 inches the next 48 hours across the lower North Carolina coast. Any regions that receive a long duration of high rainfall rates may see the possibility of flash flooding. The other system within the southern stream is a slow moving closed low currently crossing the California/Arizona border. The disturbance should eventually evolve into more of an open wave as it migrates into the Four Corners region on Saturday. A disorganized area of showers and thunderstorms should develop with no real focus visible at the surface. Orographics should play a role in local enhancements across the Southern Rockies. Given the unstable air mass this system will be encountering across the Southern High Plains, there will be a threat for severe weather over West Texas on Sunday. Looking to the north, an active northern stream of the jet will carry a series of systems eastward with decent separation between each disturbance. While there is sufficient amplitude in the upper flow to allow colder air to work its way southward, it should not make it beyond Northeastern Minnesota/Upper Peninsula of Michigan while most of the wintry impacts will be north of the international border. Precipitation overrunning the warm front should bring a mixture of freezing rain and snow to sections of Northeastern Minnesota and possibly into portions of the Upper Peninsula of Michigan. Otherwise, light to moderate rain will fall from the Central Plains and into the Middle Mississippi Valley along a slow moving cold front. Across the Pacific Northwest, the series of disturbances migrating through the region should bring periods of rain to the lower elevations and snow across the Washington Cascades as the low-level flow becomes more onshore. The general lack of cold air should limit snowfall amounts to only 4 to 6 inches across this range through Monday morning. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php