


Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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436 FXUS01 KWBC 151931 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 330 PM EDT Tue Jul 15 2025 Valid 00Z Wed Jul 16 2025 - 00Z Fri Jul 18 2025 ...Heavy rainfall and flash flood threat continues for portions of the Mid-Atlantic and Appalachians into mid-week... ...Heavy downpours and possible flash flooding expected with a tropical disturbance moving across Florida into the northern Gulf... ...Potent summer storm system to bring flash flooding and severe weather to the Midwest and northern/central Plains through midweek... ...Heat threat building across much of the eastern U.S. through at least mid-week... A moisture-rich summer airmass will remain in place across much of the eastern and central U.S. through midweek, supporting scattered to widespread showers and thunderstorms capable of producing heavy downpours and flash flooding. A slow-moving and weakening front stretching from the Mid-Atlantic into the Ohio Valley will act as a key focus, with abundant moisture along and south of the boundary fueling rounds of heavy rainfall. Thunderstorms developing this afternoon are likely to continue into the evening hours before gradually diminishing overnight. The greatest concentration of activity today is expected from the central and southern Appalachians through the southern Delmarva Peninsula. On Wednesday, this axis will lift farther north, with the heaviest rainfall expected from the upper Ohio Valley into the northern Mid-Atlantic. Across Florida and the Gulf Coast, the National Hurricane Center continues to monitor a tropical disturbance drifting westward across the peninsula into the northern Gulf of Mexico. Even if the system does not undergo further development, deep tropical moisture and associated thunderstorm activity will bring the potential for heavy rainfall and localized flash flooding across portions of Florida and the eastern to central Gulf Coast through the period. Farther west, a well-defined cold front will push east from the Upper Midwest into the Northeast while sagging south into the northern and central Plains through midweek. This boundary will serve as a focus for multiple rounds of showers and thunderstorms, some of which may become strong to severe and produce heavy rainfall. The Storm Prediction Center has highlighted parts of central Nebraska with an Enhanced Risk (Level 3 of 5) for severe weather, where scattered damaging wind gusts and large hail are likely later this afternoon into the evening. Elsewhere along and ahead of the front, a broader area from the Upper Midwest to the northern Great Basin remains at risk for scattered strong to severe storms into the evening hours. By Wednesday, the severe threat shifts farther south along the front, with scattered strong to severe thunderstorms expected during the afternoon and evening from portions of the central High Plains eastward into the Great Lakes. Damaging wind gusts are expected to be the primary hazard, with large hail also a concern, particularly across parts of the central High Plains. Ahead of the front, the persistent humid airmass will lead to increasingly uncomfortable conditions. Daytime highs are forecast to climb into the 90s as far north as northern New England, while overnight lows will offer limited relief. Major HeatRisk (Level 3 of 4) will expand across portions of the eastern U.S., including the Ohio, Tennessee, and lower Mississippi Valleyssignaling dangerous heat impacts, particularly for vulnerable populations without access to cooling or adequate hydration. In sharp contrast, a much cooler airmass will surge in behind the front. Well-below normal temperatures are expected across the northern and central Plains and the Upper Midwest, with daytime highs running 20 to 30 degrees below average over the northern High Plains on Wednesday. West of the Rockies, temperatures will remain above normal, with highs reaching near 100 degrees across parts of the Pacific Northwest. Across the Southwest, a shift toward cooler, below-normal temperatures is expected beginning Tuesday, as increasing monsoonal moisture brings greater cloud cover and a daily chance for scattered showers and thunderstorms. Pereira Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$