666 FXUS21 KWNC 251808 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT September 25 2026 SYNOPSIS: A cold front is forecast to shift southward across the Southeast and Gulf Coast on Oct 3 and 4 with an elevated risk of heavy precipitation. Behind this cold front, at least a brief period of cooler-than-normal temperatures are expected to overspread the central U.S. There is an increasing chance of the first widespread frost or freeze of the season for the northern to central Great Plains, western Corn Belt, and Upper Midwest. A series of low pressure systems with enhanced onshore flow results in a slight risk of heavy precipitation and high winds for south-central and southeastern Alaska. HAZARDS Slight risk of heavy precipitation for parts of the Southeast and Gulf Coast, Sat-Sun, Oct 3-4. Slight risk of heavy precipitation for the Florida Peninsula, Sat-Fri, Oct 3-9. Slight risk of much below-normal temperatures for the northern to central Great Plains, western Corn Belt, and Upper Midwest, Sun-Tue, Oct 4-6. Slight risk of heavy precipitation for parts of south-central and southeastern Alaska, Sat-Fri, Oct 3-9. Slight risk of high winds for coastal parts of south-central and southeastern Alaska, Sat-Fri, Oct 3-9. DETAILED SUMMARY FOR MONDAY SEPTEMBER 28 - FRIDAY OCTOBER 02: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SATURDAY OCTOBER 03 - FRIDAY OCTOBER 09: The GEFS and ECENS are in better agreement today with an amplifying 500-hPa ridge over western North America during early October, which results in a cold front advancing southward across the Southeast and likely south of the Gulf Coast by Oct 5. Ahead of the cold front, there is a slight risk of heavy precipitation for parts of the Southeast and Gulf Coast on Oct 3 and 4. This is supported by 24-hour precipitation amounts from the GEFS and ECENS along with good model continuity. The slight risk of heavy precipitation continues through the end of week-2, Oct 9, across the Florida Peninsula as a stationary front may be a focus for enhanced rainfall across the region. The Bay of Campeche will have to be closely monitored for tropical cyclone (TC) development through early to mid-October. Following Hurricane Polo in the East Pacific, the National Hurricane Center (NHC) states that there is a 90% chance of another tropical cyclone (TC) forming offshore of southwestern Mexico within the next week. By week-2, there is a large spread among the GEFS and ECENS ensemble members on the eventual track of this likely TC. Therefore, uncertainty is high on how much if any rainfall shifts north into the Desert Southwest from Oct 3-9. In the wake of a strong cold front for early October, multi-model ensemble mean solutions are in good agreement indicating a surface high shifting south from Canada into the north-central U.S. A slight risk of much below-normal temperatures, valid Oct 4-6, is posted for the northern to central Great Plains, western Corn Belt, and Upper Mississippi Valley where the ECENS Probabilistic Extremes Tool (PET) depicts >20% chance of minimum temperatures falling below freezing and the 15th percentile climatologically. This would be the first widespread frost and freeze of the season for these areas. Typically, the first freeze of the fall occurs either in late September (northern Plains) or early October (central Plains and western Corn Belt). A highly amplified 500-hPa trough over the northeast Pacific is likely to promote a series of low pressure systems to track from the Alaska Peninsula eastward to the Gulf of Alaska. Based on the enhanced onshore flow, associated with these low pressure systems, and support from the ECMWF and GEFS PETs (20% chance of 3-day precipitation amounts > 85th percentile and 3 inches), a slight risk of heavy precipitation is designated from the Kenai Peninsula to southeastern Alaska. Since the GEFS, ECENS, and CMCE persist the deep 500-hPa trough over the North Pacific through early October, the heavy precipitation hazard is maintained for the entirety of week-2. Although most of the model ensemble members only depict surface lows of moderate strength, a slight risk of high winds is maintained based on pattern recognition and support from the ECENS PET wind tool. The high wind hazard is also valid from Oct 3-9. FORECASTER: Brad Pugh $$