Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 405 PM EDT Wed Apr 05 2017 Valid 00Z Thu Apr 06 2017 - 00Z Sat Apr 08 2017 ...A strong low pressure system is expected to bring strong to severe thunderstorms across the Southeast tonight followed by wet and windy conditions up the East Coast into Friday... ...Moisture moving into the West Coast will culminate on Friday over northern California as a strong Pacific storm approaches... A low pressure system currently centered over the Ohio Valley is forecast to strengthen as it reaches western New York later on Thursday. Strong upper-level dynamics combining with a warm and moist air mass along with a subtle low-level boundary will support the formation of widespread strong to severe thunderstorms in the southeastern U.S. through tonight ahead of a strong cold front. As the cold front sweeps steadily towards the Eastern Seaboard Thursday morning, a new low pressure center is forecast to form in the interior mid-Atlantic. Wind and rain will intensify ahead of this new low pressure center as the storm intensifies rapidly and heads generally northward towards western New England through Thursday night. The low should reach peak intensity early on Friday when the center loops across western New York and the lower Great Lakes. The size of the storm will become very large at that point with the circulation engulfing almost the entire eastern U.S. The large storm will pull down cold air from Canada, changing the rain to snow from over lower Michigan down into the Ohio Valley and as far south as the central Appalachian, where the snow should last into much of Friday as the storm gradually weakens over New England but slow to move out. Cold temperatures for April will be funneled down through the Plains states, even into Florida through Friday! Out West, moisture ahead of a Pacific front has been slowing edging further inland. The front is expected to become nearly stationary near the coast tonight into Thursday before a much stronger low pressure system from off the Pacific quickly approaches Thursday night. Heavy rain associated with a high moisture plume is expected to move into northern California Thursday night where flooding could become an issue. The precipitation will spread farther south into central California on Friday with snow expected to fall over the Sierra Nevada. Farther north, precipitation will continue to overspread much of the Pacific Northwest, the Great Basin, into the Intermountain region and northern Rockies on Friday. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php