105 FXUS21 KWNC 221813 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT September 22 2026 SYNOPSIS: A stationary front and enhanced moist flow are expected to set up across the Florida Peninsula and Gulf Coast, in addition to a series of fronts sweeping across the central and eastern CONUS during week-2. This pattern may bring enhanced rainfall to these regions, with the greatest chances for heavy rain across the Southern Plains, Lower Mississippi and Tennessee Valleys, and Southeast U.S. There is an increased likelihood of high winds across parts of the California Coast associated with a tight pressure gradient, with surface low pressure over the West Coast and Southwest and adjacent surface high pressure over the Northeast Pacific. Surface low pressure in the Gulf of Alaska has the potential to bring increased precipitation and winds to parts of southern Alaska at times, and the continuing active tropical season in the East Pacific increases the chances that at least one disturbance impacts Hawaii. HAZARDS Slight risk of heavy precipitation for parts of the Southern Plains, Lower Mississippi and Tennessee Valleys, and the Southeast U.S., Wed-Sun, Sep 30-Oct 4. Slight risk of episodic high winds for parts of the California coast, Wed-Tue, Sep 30-Oct 6. DETAILED SUMMARY FOR FRIDAY SEPTEMBER 25 - TUESDAY SEPTEMBER 29: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR WEDNESDAY SEPTEMBER 30 - TUESDAY OCTOBER 06: Dynamical models generally indicate fairly zonal mid-level flow with a series of shortwave troughs propagating across the CONUS during week-2. A series of fronts are anticipated to track across the central and eastern CONUS while a stationary front meanders across the Gulf Coast and Florida. These features combined with periods of enhanced onshore flow over the south-central and southeastern CONUS and possible surface low formation in the Gulf supports periods of enhanced rainfall across the central and eastern CONUS. The risk of heavy rain is expanded in coverage compared to yesterday due to uncertainty in where the heaviest precipitation will occur and more widespread potential in the Probabilistic Extremes Tools (PETs) and uncalibrated guidance. A broad area is highlighted with a slight risk of heavy precipitation across portions of the Southern Plains, Lower Mississippi and Tennessee Valleys, and Southeast U.S., Sep 30-Oct 4. The greatest chances for heavy rain across the Southern Plains/Lower Mississippi Valley would be at the beginning of week-2. Multiple PETs indicate 3-day rainfall totals exceeding the 85th percentile climatologically and one inch. Rainfall would be beneficial in areas where antecedent conditions have been dry. Some areas of heavy rain including potential thunderstorms are possible in these areas, potentially triggering isolated flash flooding, although no particular area appears vulnerable to widespread and persistent flood conditions. Potential surface low formation over Baja California, the West Coast, and Southwest further enhanced by tropical cyclones nearing Baja California, combined with adjacent surface high pressure near or just offshore the West Coast, may result in a tight pressure gradient across parts of coastal California. This pattern may result in periods of enhanced wind speeds across coastal portions of California, thus a slight risk of episodic high winds is designated throughout week-2. This is supported by the PETs indicating at least a 20% chance of wind speeds exceeding the 85th percentile and 25 mph (35 mph locally) and model ensembles showing increased chances of wind gusts exceeding 34 knots (about 40 mph) in the region. Mid-level troughing is expected to be centered over Alaska and the Gulf of Alaska throughout week-2, supporting surface low formation in the Gulf of Alaska. In general the models indicate a more favorable pattern for a stronger low and associated onshore flow from the Gulf of Alaska toward the end of week-2 which may bring enhanced rainfall and gusty winds to south-central and southeastern Alaska. No hazards are designated at this time but will be monitored closely in the upcoming days. As the active tropical season continues in the Eastern Pacific, tropical cyclone (TC) development enhances the odds of at least one system bringing hazardous impacts to Hawaii. Grounds are saturated in many areas due to periods of heavy rain over the past few months, and any additional episodes of heavy rain may renew impacts caused by the wetness, such as flooding and possibly mudslides. At this time, several areas of potential tropical development are being monitored in the Central and Eastern Pacific, including the remnants of Tropical Depression Fifteen-E currently located several hundred miles southeast of Hawaii as of 8am HST and currently has a high (90 percent) chance of TC formation over the next 7 days according to the National Hurricane Center, with possible lingering impacts to the island chain at the beginning of week-2. FORECASTER: Melissa Ou $$