Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 346 PM EDT Wed Apr 10 2024 Valid 00Z Thu Apr 11 2024 - 00Z Sat Apr 13 2024 ...Heavy rain, flash flooding and severe weather threat associated with a strengthening storm system to continue this afternoon and tonight in the Southeast... ...Powerful storm system to foster heavy rain and high wind potential over much of the eastern U.S. on Thursday; severe weather and flash flood threats forecast in parts of the Southeast and upper Ohio Valley... ...High winds along with widespread moderate to heavy rain expected to impact the entire Eastern Seaboard into the Great Lakes Thursday night into Friday; warming up in the West... The second half of the work-week features an impressive early-mid April storm system, currently tracking through the Deep South, that will head northeast through the Lower Mississippi Valley this evening and head for both the Tennessee and Ohio Valleys come Thursday morning. The central Gulf Coast is the focus for the most dangerous weather this afternoon and evening as organized thunderstorms track east through the region. The Storm Prediction Center and Weather Prediction Center both issued Moderate Risks for severe storms and Excessive Rainfall respectively, implying that not only is flash flooding anticipated for parts of the central Gulf Coast, but so are severe thunderstorms capable of producing tornadoes, damaging wind gusts, and large hail. Meanwhile, periods of rain will be common from the ArkLaTex and Ozarks this afternoon to the Ohio Valley and Lower Great Lakes overnight. By Thursday morning this strengthening storm system will direct its shield of rain north into the eastern Great Lakes and Mid-Atlantic, then finally into the Northeast by Thursday afternoon. Numerous showers are also still expected in parts of the Lower Mississippi Valley and for much of the Ohio and Tennessee Valleys. In terms of severe weather the upper Ohio Valley is most at-risk, as evident with an expansive Slight Risk area and a smaller Enhanced Risk area that is focused in eastern Ohio and western West Virginia. Tornadoes and damaging winds are the primary modes of severe weather of greatest concern through Thursday afternoon. Farther south, the storm's cold front will act as a trigger for severe storms from the Mid-Atlantic on south to northern Florida. SPC has a Slight Risk that stretches from southern South Carolina on south to the Tampa, FL metro area. There is also the threat for Excessive Rainfall and resulting flash flooding from the Upper Ohio Valley on east through the northern Mid-Atlantic. WPC has a large Slight Risk area in place for portions of these regions, with metro areas such as Pittsburgh, Washington D.C., Baltimore, and Philadelphia all within the Slight Risk zone. In addition to the rain and thunderstorms, gusty winds will be felt across much of the eastern half of the U.S., especially in the central Appalachians and parts of the Southeast where Wind Advisories are in place for tomorrow. By Friday, while the severe threat backs down, there is a Slight Risk for Excessive Rainfall in portions of northern New Hampshire and western Maine. Gusty winds, as well as widespread showers are anticipated in the Great Lakes and Mid-Atlantic during the day Friday. In the West, a tranquil weather pattern this afternoon and through Thursday along the West Coast will conclude as the next Pacific storm system delivers showers and mountain snow to the Pacific Northwest by Thursday night. The storm system dive south along the West Coast and a frontal boundary will set up over the Northern Rockies. This will lead to hit-or-miss showers from the Sierra Nevada and Oregon Cascades on east through most of the northern Rockies Friday afternoon. Temperature-wise, an expansive swath of unusually warm temperatures for mid-April will grow east from the West Coast and the Great Basin today and Thursday, to eventually engulfing much of the Great Plains by Friday. Meanwhile, cool northwest winds on the backside of the large eastern U.S. storm system ushers in a below normal air-mass into the Mississippi Valley and Mid-South on Thursday. While these areas warm up by Friday, the same regime of cooler than normal temperatures moves east into the Great Lakes, Ohio Valley, Mid-Atlantic, and the Southeast. Mullinax Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php