Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 AM EDT Wed May 19 2021 Valid 12Z Wed May 19 2021 - 12Z Fri May 21 2021 ...There is a Moderate Risk of excessive rainfall over the Central/Western Gulf Coast through Friday... ...There is a Slight Risk of severe thunderstorms over parts of the southern tip of Texas through Thursday morning... ...Late-season snow is expected for the Cascades, Northern Rockies, and higher elevations of the Intermountain West... ...There is a Critical Risk of fire danger across the Great Basin and Southwest... Moisture from the Western Gulf of Mexico will continue to flow across the Plains and Mississippi Valley through Friday. Upper-level energy over the Plains will trigger showers and thunderstorms over the region through Friday. The WPC has issued a Moderate Risk of excessive rainfall over the Central/Western Gulf Coast through Friday. The showers and thunderstorms will produce heavy rain over the region producing numerous areas of flash flooding. Additionally, the heavy rain may cause many streams and possibly larger rivers to flood. The SPC has issued a Slight Risk of severe thunderstorms over parts of the southern tip of Texas through Thursday morning. The main threats from the severe thunderstorms are frequent lightning, severe thunderstorm wind gust, hail, and a few tornadoes. On Thursday, the excessive rainfall threat continues over parts of the Western/Central Gulf Coast. Meanwhile, the threat of severe thunderstorms moves northwestward to parts of the Northern/Central High Plains on Thursday. Aiding in this shift is front becoming quasi-stationary from parts of the Upper Midwest to the Southwest through Friday. The boundary and weak onshore flow will produce rain and higher elevation snow over the Pacific Northwest into the Northern Rockies through Friday. A developing upper-level low over the western portion of the country aids in producing gusty winds and low relative humidity led to a Critical Risk of fire weather over portions of the Great Basin into the Southwest through Friday. The eastern U.S. will see mainly dry conditions under high pressure, with only a few showers and thunderstorms over parts of Florida. Temperatures will become above average as an upper-level ridge develops east of the Mississippi Valley, with temperatures in the 80s in most places. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php