406 FXUS01 KWBC 040819 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 418 AM EDT Sun Oct 04 2026 Valid 12Z Sun Oct 04 2026 - 12Z Tue Oct 06 2026 ...Moderate risk of excessive rainfall today along the lower Texas coast while a slight risk extends from the central Gulf Coast through the Southeast... ...A long duration October heatwave building across central and southern California, and spreading into the Great Basin... Heavy rainfall threat will remain focused along the Gulf Coast and across the Southeast, while an anomalous October heatwave builds across the western U.S. The lingering wet weather pattern is the result of continued interaction of a tropical wave in the Gulf with a cool and dry air mass that has settled across the eastern two-thirds of the country. The Weather Prediction Center now highlights a Moderate Risk of excessive rainfall for the lower Texas coast for today and tonight as additional heavy rain bands forming along a stationary convergence zone just offshore are expected to swing onshore. Meanwhile, moderate to heavy rainfall near a wavy stationary front is forecast to overspread the central Gulf Coast through the Southeast and into the Carolinas. The heaviest forecast rainfall remains near the Gulf Shores to the western portion of the Florida Panhandle where a maximum of 7 inches is possible with the passage of a convection cluster. Flood Watches are in effect from coastal Mississippi to the Florida Panhandle. The heavy rainfall threat will gradually decrease late tonight and into Monday morning for the Southeast and along the Gulf Coast as the front nudges farther south. However, heavy rainbands associated with the stationary offshore convergence zone will be slow to depart the lower Texas coast through much of Monday. Meanwhile, a low pressure system sweeping across the Canadian border will fuel scattered showers and thunderstorms across the Great Lakes this morning. A strong cold front trailing from the intensifying system could bring heavy showers and embedded thunderstorms into interior New England by early Monday morning. Across the Mid-Atlantic, showers behind a cold front early this morning will move off the coast as the cool air mass from the Ohio Valley to the Northeast takes over. A high pressure system across the Great Lakes to the Midwest will build eastward, delivering fine and cool fall weather for much of the eastern U.S. Monday and Tuesday except the Sunshine state where showers and thunderstorms associated with the wavy front persist. While the wet pattern persists across the South, an anomalous ridge of high pressure will build a late season October heatwave across the western U.S. through this week. Temperatures will run 15 to 20 degrees above normal, bringing highs well into the 90s toward the coast and adjacent urban areas, with some areas in the Central Valley of California soaring into the lower 100s. Overnight lows in the mid to upper 70s in the Los Angeles and San Diego urban areas will provide little relief through the heatwave. Extreme Heat Warnings are in effect for much of Southern California, with Heat Advisories extending across the Central Valley and Bay Area. The heat will then expand farther northeast over the next couple of days, with high temperatures in the 80s and near 90 degrees emerging across the Great Basin. A few daily temperature records could fall over the next few days in California and the Great Basin as a result. Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$