117 FXUS01 KWBC 201928 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 327 PM EDT Mon Jul 20 2026 Valid 00Z Tue Jul 21 2026 - 00Z Thu Jul 23 2026 ...A strong southeastward moving frontal system to support active thunderstorms and flash flooding risks from the Upper Midwest into the Mid-Atlantic... ...T.D. Two to bring heavy rain threats across the Gulf Coast... ...Monsoonal thunderstorms to continue over the next few days from the Southwest into the Great Basin... ...Hazardous heat builds across the Southern Plains and Southeast... ...Canadian wildfire smoke brings Air Quality concerns over northern U.S. over the next few days... An amplified ridge over western and southern U.S. will dominate much of CONUS, while a series of shortwave troughs will travel along the northeast side of the ridge across Midwest/Great Lakes into the upper level trough across the Northeast. This will aid the southeastward progression of a few frontal boundaries ejecting from southern Canada into portions of the Midwest into the Ohio Valley, Mid-Atlantic and Northeast, which will serve as a primary focus for organized convection and heavy rainfall along the boundary. The system will bring severe thunderstorms, damaging winds, isolated very large hail, flash flood threat, and the possibility for a few strong-intense tornadoes across the Upper Midwest/Great Lakes into Tuesday. As the system drops further southeast on Wednesday and interact with warm tropical moisture, chances for heavy rainfall will increase, posing a risk for flash flooding across the Upper Ohio Valley into the Mid-Atlantic. Across the northeast Gulf, Tropical Depression Two is forecasted to move from the Florida Panhandle westward to southern Louisiana and strengthen into a Tropical Storm. This will bring storm surge along the shoreline, heavy precipiation/flash flooding risk along the Alabama, Mississippi, Louisiana and the Middle Texas coastlines through Wednesday. See the latest NHC advisories for additional and updated information on this storm. Over into the southwest, monsoonal moisture circulating around the western periphery of the ridge will continue to support scattered afternoon and evening thunderstorms across the central and southern Rockies. Storm motions will generally remain slow, producing locally heavy rainfall, especially over higher terrain through Wednesday. Across the Southeast and southern Plains, a subtropical ridge will bring anomalous warm temperatures and widespread heat with afternoon highs in the upper 90s into lower 100s, with dewpoints remaining in the upper 70s. This will lead to heat indices exceeding 105-115 F in isolated locations. This heat stress has lead to widespread major, to locally extreme, Heat Risk across much of the Southeast and Southern Plains. With the addition of little overnight recovery, as lows are expected to drop to 75-80 F, heat related illness may be of concern over the next few days, especially for those without adequate cooling or hydration. Further north, below normal temperatures will build behind the cold front, across the Upper Midwest/Great Lakes into the Northeast. As the wildfires persist across portions of Canada, the much of the northern U.S. will continue to experience poor air quality over the next few days. The models continue to show smoke returning southward across into the Upper Midwest/Great Lakes region. Additionally, the fires will bring air quality concerns over the Pacific Northwest and Northern Rockies, where several Air Quality Alerts have been issued. Oudit Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$