334 FXUS01 KWBC 251957 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 PM EDT Sat Jul 25 2026 Valid 00Z Sun Jul 26 2026 - 00Z Tue Jul 28 2026 ...Chances for showers and thunderstorms across the Northern Rockies/Plains into Upper Midwest this weekend... ...Risk of flash flooding expected across Southeast and southern Mid-Atlantic near a stalled frontal boundary... ...Active monsoonal moisture fuels thunderstorms over the Southwest and into portions of the Intermountain West and Rockies... ...Hazardous heat continues over parts of southern U.S. and builds over the Great Basin and Northern Plains through the weekend... A broad upper ridge with be anchored over the southern and central U.S. into next weekend. Hazardous heat is expected across the southern tier and will be steadily building into the Great basin and Northern Plains. There will be widespread Major HeatRisk with isolated Extreme HeatRisk areas from the Rockies/High Plains eastward to th the Mississippi Valley and south to the Gulf Coast. Daily maximums generally ranging in the upper 90s to lower 100s for the central and southern states and with isolated areas in the Desert Southwest seeing 115-120 degrees. High temperatures combined with high humidity can raise heat indices to 105 to 115 degrees, which will pose health risk concerns to anyone without adequate cooling or hydration. Deep tropical moisture will continue to circulate along the southern periphery of the ridge into the Southwest and Great Basin regions. Diurnal heating and plentiful instability will help trigger showers and thunderstorms across the Four Corners and into the Central Plains. Locally heavy rainfall will be possible especially over burn scars and slot canyons where rapid runoff and flash flooding may occur. Additionally, Storm Prediction Center has highlighted portions of Arizona with a severe thunderstorm threat, with a potential for strong to severe winds for Saturday. On the north side of the ridge embedded shortwave disturbances will be tracking across the northern tier driving a frontal boundary eastwards from the Northern Rockies/Plains into the Upper Midwest/Great Lakes on Saturday. Low-level moisture pooling along the boundary, combined with strong daytime heating and instability, will support isolated thunderstorm development across portions of Northern Rockies into the Upper Midwest, with a chance for large hail and damaging gusty winds. The severe weather threat increases on Sunday, as several shortwave disturbances shift eastward and mid-level flow increases, reinforcing organized thunderstorms from the Upper Mississippi Valley into the Upper Midwest. These storm may also produce heavy rainfall, damaging wind gust, and isolated instances of flash flooding where antecedent soils are saturated. As the front moves into the eastward by late Sunday into Monday, showers and thunderstorms may develop along the boundary across portions of the Ohio Valley into the Mid-Atlantic. A secondary quasi-stationary front will drape across the Tennessee Valley into the south Mid-Atlantic and the Southeast on Saturday. Persistent southerly flow ahead of the approaching front will maintain a warm and humid air mass. With abundant moisture, slow storm motions, and high rainfall rates, a Slight Risk (level 2/4) of excessive rainfall have been placed for scattered instances of flash flooding over portions of the eastern Carolinas and the Southeast, while a Marginal Risk (level 1/4) includes portions of the Tennessee Valley. Flash flooding concerns continue for portions of Florida on Sunday as a shortwave trough and the stationary front continues to produce showers and thunderstorms. Campbell/Oudit Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$