501 FXUS21 KWNC 041821 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT October 04 2026 SYNOPSIS: A stalled frontal boundary over the Gulf Coast, along with deep tropical moisture is favored to produce widespread heavy and potentially hazardous precipitation and elevated wind speeds across the region through the middle of week-2, particularly along the central and eastern Gulf Coast. Low pressure at the surface and mid-levels is favored to transit from the Bering Sea to the Gulf of Alaska, bringing the potential for high winds and heavy precipitation for much of the southern and southeastern coast of the state through the middle of the forecast period. HAZARDS Slight risk of heavy precipitation for parts of the Upper Texas coast, much of the Lower Mississippi and Tennessee Valleys, Southeast, Mid-Atlantic, and much of New England, Mon-Tue, Oct 12-13. Slight risk of high winds for most of the Gulf Coast, Mon-Fri, Oct 12-16. Slight risk of heavy precipitation for parts of southcentral and southeastern Alaska, Mon-Fri, Oct 12-16. Slight risk of high winds across the Aleutians, Alaska Peninsula, and coastal portions of southwestern, southcentral, and southeastern Alaska, Mon-Fri, Oct 12-16. Flooding possible for much of the Gulf Coast region including northern and central Florida. DETAILED SUMMARY FOR WEDNESDAY OCTOBER 07 - SUNDAY OCTOBER 11: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR MONDAY OCTOBER 12 - SUNDAY OCTOBER 18: The GEFS and ECENS continue to be in good agreement on the large-scale height pattern, with the 7-day average height pattern featuring a mean ridge axis near the West Coast, a broad trough over the Central and interior Eastern contiguous U.S. (CONUS), zonal flow across the North Atlantic, and a trough over the Bering Sea and western Alaska. South and east of the mid-level troughing predicted east of the Rocky Mountains, a stationary front is forecast to extend from near the Gulf Coast to the Southeast Coast. This pattern supports a prolonged period of episodic heavy rainfall for much of the Gulf Coast, Florida, Tennessee, and from the Appalachians eastward to the Atlantic coast through the first few days of week-2, where a slight risk for heavy precipitation is posted, Oct 12-13. For approximately the Mid-Atlantic and much of New England, the heavy precipitation is expected to come mostly from a northern stream trough moving across the Great Lakes region.The GEFS and ECENS Probabilistic Extremes Tools (PETs) agree on at least a 20% chance of 3-day precipitation totals exceeding the 85th percentile and one inch across the designated hazard area through day 10, with the ECENS topping out near 30%. This is also well supported by the uncalibrated precipitation forecasts from these ensemble means. Shortly before the start of week-2, WPC predicts a wave will develop over or near the western and central portion of the stationary front situated near the Gulf Coast. Surface high pressure moving off the Mid-Atlantic coast will help strengthen and sustain the moist, southerly, onshore flow from the Gulf of America northward into the Gulf Coast states and Southeast. Whether or not this wave disturbance becomes a full-fledged tropical system, or whether it originates entirely from the Bay of Campeche is unclear at this time. As of today (Oct 4), the National Hurricane Center has a 40% (medium) chance of tropical cyclone formation within the next 7-days over the Bay of Campeche. A slight risk of high winds (at least 25 mph) is also posted for most of the Gulf Coast, Oct 12-16, which is tied to the elevated potential of lower surface pressure over the Gulf. This is supported by predicted GEFS/ECENS surface low pressure center distributions, and the ECENS wind PET. Anticipated heavy rainfall and strong onshore flow, combined with expected enhanced rainfall totals from week-1 (ranging from 2-7+ inches near the coast), could lead to widespread potential for urban and flash flooding across the central and eastern Gulf Coast. Therefore a flooding possible hazard remains valid for the affected region, which includes northern and portions of central Florida. Caution is highly advised with regard to flooded roads and waterways and if widespread flooding is occurring in your area, unnecessary travel is strongly discouraged. For the western CONUS, model ensemble solutions favor mid-level troughing and somewhat cooler temperatures early in week-2, giving way to ridging and warmer temperatures for the second half of the outlook period. The possibility of renewed heat in southern California will need to be reassessed, noting areas around Los Angeles yesterday reached between 100-105 F. In addition, with the tropical eastern Pacific continuing to be very active, there is an elevated chance of increased moisture influx into the Southwest due to recurving tropical cyclones and/or gulf surges. Conditions will be reassessed tomorrow to see if there is enough confidence to justify any temperature or precipitation risks for the Southwest. An amplified 500-hPa trough over the Bering Sea and western Alaska is likely to promote a series of low pressure systems that track from the Bering Sea and Alaska Peninsula eastward to the Gulf of Alaska. This favors widespread onshore flow to most of coastal southern Alaska, and results in 2-3 inch precipitation amounts according to the GEFS and ECENS model ensembles. Uncalibrated and PET precipitation guidance supports this hazard at least into the middle portion of week-2, with precipitation totals exceeding the 85th percentile. An even greater concern regarding impacts for the state would be for high winds, as this is the time of year when western Pacific typhoons often recurve into the temperate westerlies and have a significant impact on the circulation pattern downstream over Alaska. The specific details regarding timing and intensity of impacts are very uncertain, but for now a broad slight risk of high winds is depicted for the entire southern coast of Alaska, Oct 12-16, for wind speeds of at least 40 mph. FORECASTER: Anthony Artusa $$