Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
Versions:
1
2
951 FXUS01 KWBC 080804 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 AM EDT Tue Sep 08 2026 Valid 12Z Tue Sep 08 2026 - 12Z Thu Sep 10 2026 ...Strong to severe thunderstorms with heavy rainfall shift southeastward into the Midwest today, stretching from the Midwest to interior New England by Wednesday night... ...Modest relief from the heat across the midsection of the country by late Wednesday as some heat returns to the Mid-Atlantic.... As a large high-pressure system brings fine and cool weather across much of the eastern U.S., a frontal system trailing from an intensifying low-pressure system across southern Canada has triggered strong to severe thunderstorms scattered across the upper Midwest to the central Plains early this morning. The southern portion of the front will begin to lose momentum, allowing showers and thunderstorms to develop and move more slowly across the north-central Plains, gradually advancing across the Upper Midwest and reaching the Great Lakes by tonight. WPC continues to highlight a slight risk of excessive rainfall across Iowa as SPC maintains a slight risk of severe thunderstorms for the same general area today into early Wednesday. By Wednesday, showers and thunderstorms are expected to stretch from the central Plains, through the Midwest and Ohio Valley, reaching into interior New England by Wednesday night as the front advances gradually to the south and east. WPC now highlights a slight risk of excessive rainfall across central Missouri into adjacent areas for Wednesday into early Thursday. As the high pressure system continues to expand southward into the eastern U.S. against the heat dome anchored over the country`s midsection, a frontal boundary will remain stalled across the eastern Gulf Coast and the Florida Peninsula. This pattern will allow scattered showers and embedded thunderstorms to linger across the eastern Gulf Coast region, including the Sunshine State, through the next few days. Meanwhile, much of the Northeast and Mid-Atlantic will begin a gradual warming trend towards more seasonable temperatures as the cool airmass begins to moderate. The exception will be across northern New England where a reinforcing surge of cold air is forecast to drop temperatures into the 30s by Wednesday morning. Temperatures across the western U.S. will follow a similar warming trend starting today as mid-level heights rise with the departure of the lingering upper-low. East of the Rockies, some much needed relief from the oppressive heat is in store late Wednesday with the arrival of the trailing cold front from the Canadian cyclone. Until then, however, daytime highs in the upper-90s and triple digits combined with record warm temperatures will maintain dangerous heat today into Wednesday from the central Plains to the mid-Mississippi Valley. Some heat is expected to return to the Mid-Atlantic as highs climb back into the upper 80s. Elsewhere, some late-day monsoonal showers and storms will maintain a marginal risk of flash flooding mainly across Arizona and New Mexico through the next couple of days, possibly extending into interior California on Wednesday. Kong/Asherman Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php Extreme Heat Key Messages available at: https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png $$