246 FXUS01 KWBC 181930 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 328 PM EDT Thu Jun 18 2026 Valid 00Z Fri Jun 19 2026 - 00Z Sun Jun 21 2026 ...Remnants of Tropical Storm Arthur to maintain a substantial flash flooding threat across the Gulf Coast and Southeast... ...A developing low-pressure system will bring a renewed threat of showers and thunderstorms to the Central and Southern Plains by Saturday... ...An active cold front will clear the East Coast, ushering in cooler and significantly drier conditions for the weekend, while the West remains hot to end the week... The deep tropical moisture plume associated with the remnants of Tropical Storm Arthur will continue to maintain a substantial flash flooding threat across the Gulf Coast states and the Southeast over the next couple of days. Strong low-level flow around a surface ridge over the Southeast will continue to transport tropical moisture east-northeastward, supporting widespread clusters of heavy showers and thunderstorms across eastern Texas, Louisiana, Mississippi, Alabama, and into the Florida Panhandle and Georgia. These storms will have the potential to produce torrential rainfall, and given highly saturated soils from recent precipitation, rainfall will be capable of inducing considerable flash and urban flooding. As such, there is a High Risk (level 4/4) of excessive rainfall in this region for the rest of today. Heavy rainfall is then expected to continue into Friday in much of the Southeast, particularly in southern Mississippi and Alabama. Expected rainfall, albeit lighter than today, will continue to exacerbate flooding issues in areas where repeating storms continue. Due to persistent heavy rainfall and very saturated soils heading into Friday, there is a Moderate Risk (level 3/4) of excessive rainfall in southern Mississippi and Alabama, with a widespread Slight Risk (level 2/4) in much of the surrounding area. Farther west, another disturbance is forecast to emerge from the Western U.S. as an upper-level shortwave trough tracks eastward out of the Pacific. A surface low-pressure system is forecast to develop over eastern Colorado and the lee of the Rockies by Saturday afternoon. Strong low-level southeasterly flow will establish a robust moisture return from the Gulf back into the Central and Southern Plains. As an associated cold front approaches the region late Friday into Saturday, strong low-level convergence within a warm, moist, and unstable air mass will support the development of numerous showers and thunderstorms from North Texas northward into Oklahoma and Kansas. High moisture content, will be conducive to heavy rainfall in the Central Plains, bringing the potential for numerous instances of flash flooding. As such, there is a Moderate Risk (level 3/4) of excessive rainfall in parts of the Central Plains on Saturday. Additionally, some of these storms may become strong to severe, capable of producing damaging wind gusts and large hail, with the possibility of tornadoes. The SPC has outlined a Slight Risk (level 2/5) of severe weather for Saturday as a result. Meanwhile, across the Eastern U.S., the active cold front responsible for the recent severe weather will move off the Atlantic coast early Friday morning. In its wake, a gusty westerly to northwesterly wind will usher in a much cooler and comfortably dry post-frontal air mass, characterized by low dew points in the 50s. A return to more seasonable temperatures is expected in the Northeast and parts of the Mid-Atlantic, with widespread high temperatures in the 70s and 80s. In contrast, unseasonably warm conditions will begin to expand across the Pacific Northwest under a developing upper-level ridge, where maximum temperatures are forecast to approach the 80s and lower 90s by Sunday afternoon. Farther west, the Desert Southwest and the Central Valley of California will remain hot into the weekend, with highs hovering in the 110s and 100s, respectively. Blanco-Alcala Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$