019 FXUS01 KWBC 070909 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 506 AM EDT Wed Oct 07 2026 Valid 12Z Wed Oct 07 2026 - 12Z Fri Oct 09 2026 ...The ongoing October heatwave across central and southern California begins to show signs of letting up by Friday... ...Watching the future progress of Tropical Storm Isaias in the Gulf as lingering heavy rainfall and isolated flood threats in Florida begin to move north later on Thursday... An increasingly active weather pattern is in store heading into the latter half of the week as tropical activity ramps up and gets caught amid major changes in the upper-air pattern in the mid-latitudes. First of all, the October heatwave continues today across portions of California and the Desert Southwest, where temperatures remain 15-20 degrees above average with highs reaching into the 90s to low 100s, with overnight lows in the mid- to upper 70s providing little relief from the heat. Major to locally Extreme HeatRisk means that the heat is dangerous to anyone without adequate cooling or hydration where Heat Advisories and Extreme Heat Warnings remain in effect. Temperatures are expected to gradually cool for coastal California Thursday and then interior areas by Friday so some relief from the heat is in sight. While not dangerously hot, conditions across the western to central U.S. remain well above average for October with widespread highs in the 70s and 80s. Some daily record highs will be challenged or broken. On the other hand, conditions remain cooler and below average along the East Coast and particularly for the Northeast. Frost and Freeze related Advisories and Warnings are in place for portions of New England into northeastern Pennsylvania early this morning. Temperatures will moderate quite a bit over the next couple of days with much warmer highs into the 70s expected for most locations by Thursday, while a brief intrusion of cool air reaches interior New England by Friday. Meanwhile, tropical moisture interacting with a quasi-stationary boundary through Florida will continue to lead to widespread thunderstorms across most of the Florida Peninsula and parts of the Panhandle into coastal southeastern Georgia through the next couple of days. This occurs as Tropical Storm Isaias is forecast to intensify over the southwestern Gulf and begin tracking toward the central portion of the Gulf Coast region. Locally heavy downpours across northern to central Florida could lead to a few inches of rain daily, with isolated flooding or ponding possible, particularly in urban areas. Heavy rainfall lurking just off the Gulf Coast will begin progressing northward Thursday night as Tropical Storm Isaias is forecast to turn toward a more northerly direction, raising the threat of heavy rain reaching the Florida Panhandle by Friday morning. Please refer to the National Hurricane Center (NHC) for the latest forecast updates on this system at https://www.nhc.noaa.gov. The Weather Prediction Center will continue to collaborate with NHC on the rainfall aspects of T.S. Isaias. Otherwise, the rest of the country will be mostly dry through mid-week with only some widely scattered showers expected over the central Rockies/Four Corners region, and from the upper Great Lakes to northern New England today as a frontal system moves through. Some showers will begin to develop over the north-central Plains by early Friday morning as a low-pressure system develops on the lee side of the northern Rockies. Kong/Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$