Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
Versions:
1
2
101 FXUS01 KWBC 070806 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Mon Sep 07 2026 Valid 12Z Mon Sep 07 2026 - 12Z Wed Sep 09 2026 ...Strong to severe thunderstorms expected across the northern Rockies and the northern Plains, with heavy rain threat across northwestern Montana today, followed by strong thunderstorms across the north-central Plains Tuesday... ...Heat persists across the midsection of the country while cooler air expands further into the West Coast and eastern U.S.... ...Scattered thunderstorms linger across the Southeast... As a large high-pressure system brings fine and cool weather across the Great Lakes and the Northeast this Labor Day, a low-pressure system is spreading unsettled weather into the northern Rockies and the northern Plains. This is in response to a deep upper-level low getting ready to eject out of the northern Rockies toward southern Canada. Strong dynamics associated with this weather system will bring scattered to widespread strong to severe thunderstorms across the northern Rockies to the northern Plains as today progresses. The low-pressure system is forecast to intensify and move into the southern prairies of Canada by tonight, but the potent cold front trailing from the low center will bring a round of strong to severe thunderstorms as the front sweeps through the northern Plains today, reaching into the upper Midwest tonight. By Tuesday, the southern portion of the front will lose some momentum, allowing showers and thunderstorms to develop over the north-central Plains and advance gradually into the upper Midwest by Wednesday morning. WPC is now highlighting a slight risk of excessive rainfall across Iowa Tuesday to early Wednesday. In addition, a slight risk of excessive rainfall is maintained across northwestern Montana for today. As the cool high pressure system continues to expand southward into the eastern U.S. and encounters the heat dome anchoring over the country`s midsection, the frontal boundary will eventually stall before reaching the Gulf Coast. This pattern will allow scattered thunderstorms to linger across the Southeast, including the Sunshine State, through the next few days. Meanwhile, much of the Northeast and Mid-Atlantic will enjoy a break from the heat as high temperatures only reach into the mid-70s and low-80s for the next couple of afternoons. Morning lows dropping into the 40s and 50s will bring a first taste of Fall across New England, with a reinforcing surge of cool air reaching northern Maine Wednesday morning. Below normal temperatures beneath the upper low will expand across the West for the remainder of this weekend into the new week as daytime highs dip 10 to 25 degrees below normal, except for much of the Four Corners region. In fact, below-freezing morning temperatures are expected across the higher elevations as far south as northern California and the Sierra Nevada peaks. Meanwhile, oppressive heat will continue through Labor Day in the Nation`s Heartland with the unrelenting upper-level ridge over the nation`s midsection. Heat indices of 105 to 110 degrees and record warm overnight temperatures will be widespread across the Central/Southern Plains States and Mississippi Valley through today and into the work week. See WPC`s Key Messages for more information on the heat, limit afternoon outdoor activity if possible, and stay hydrated regardless of your Labor Day plans. 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 $$