587
FXUS21 KWNC 281823
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 28 2025
SYNOPSIS: THE MAJOR STORY LEADING UP TO THE WEEK-2 PERIOD IS THE EVENTUAL TRACK
OF TROPICAL STORM IMELDA AND ITS IMPACTS ACROSS THE SOUTHERN MID-ATLANTIC AND
SOUTHEAST. MODELS CONTINUE TO INDICATE THE CENTER REMAINING OFFSHORE, BUT
POSSIBLY GETTING CLOSE ENOUGH TO THE COAST TO RESULT IN HEAVY RAIN ACROSS THE
EASTERN CAROLINAS, EASTERN GEORGIA, AND NORTHEASTERN FLORIDA BEFORE BEING
PULLED FURTHER OUT TO SEA AS IT INTERACTS WITH THE CIRCULATION OF HURRICANE
HUMBERTO. IT IS BECOMING MORE LIKELY THAT THIS SYSTEM IS NO LONGER A FACTOR BY
THE OUTSET OF WEEK-2, BUT FRONTAL ACTIVITY STILL FAVORS ENHANCED PRECIPITATION
CONTINUING OVER PORTIONS OF THE COASTAL MID-ATLANTIC AND SOUTHEAST, INCLUDING
FLORIDA, EARLY IN THE PERIOD. LINGERING FLOODING ALSO REMAINS A CONCERN DURING
WEEK-2 ACROSS THE EASTERN CAROLINAS SOUTHWARD THROUGH THE NORTHEASTERN FLORIDA
COAST. FOR THE REMAINDER OF THE CONUS, WEEK-2 IS RATHER UNEVENTFUL, WITH THE
MID-LEVEL HEIGHT PATTERN BECOMING MORE ZONAL FAVORING INCREASED PACIFIC FLOW
AND ABOVE-NORMAL, BUT NOT HAZARDOUS TEMPERATURES.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE COASTAL MID-ATLANTIC
AND SOUTHEAST, AND FLORIDA, MON-WED, OCT 6-8.
FLOODING POSSIBLE ACROSS PORTIONS OF THE COASTAL MID-ATLANTIC AND SOUTHEAST.
RAPID ONSET DROUGHT (ROD) POSSIBLE FOR PARTS OF TEXAS AND LOUISIANA.
DETAILED SUMMARY
FOR WEDNESDAY OCTOBER 01 - SUNDAY OCTOBER 05:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR MONDAY OCTOBER 06 - SUNDAY OCTOBER 12: DURING WEEK-1, TROPICAL STORM IMELDA
IS FORECAST TO REMAIN OFFSHORE BUT COME CLOSE ENOUGH TO THE COAST TO
POTENTIALLY BRING HEAVY RAIN AND POSSIBLE FLOODING TO PORTIONS OF THE COASTAL
MID-ATLANTIC AND SOUTHEAST, WITH INLAND IMPACTS BECOMING LESS LIKELY AS MODELS,
ALONG WITH THE OFFICIAL NATIONAL HURRICANE CENTER (NHC) FORECAST, DEPICT A MORE
OFFSHORE TRACK DUE TO THE INTERACTION WITH THE LARGER CIRCULATION OF HURRICANE
HUMBERTO. ANY FLOODING MAY LINGER INTO WEEK-2 AND THE FLOODING POSSIBLE HAZARD
REMAINS POSTED ACROSS THE EASTERN CAROLINAS SOUTHWARD TO NORTHEASTERN COASTAL
FLORIDA. WHILE IMELDA IS FORECAST TO MOVE FURTHER AWAY FROM THE U.S. PRIOR TO
THE START OF WEEK-2, A LINGERING STATIONARY FRONT STILL FAVORS ENHANCED CHANCES
OF HEAVY PRECIPITATION ACROSS THE COASTAL MID-ATLANTIC AND SOUTHEAST EARLY IN
THE PERIOD, WHICH COULD ALSO EXACERBATE EXISTING FLOODING CONDITIONS. THE ECENS
PROBABILISTIC EXTREMES TOOL (PET) CONTINUES TO BE THE MOST ROBUST DEPICTING
PARTS OF THE SOUTHEAST, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, AND SOUTHERN
APPALACHIANS HAVING AT LEAST A 20 PERCENT CHANCE 3-DAY PRECIPITATION TOTALS
EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND 1-INCH. HOWEVER, THE GEFS PET
SHOWS VERY LITTLE SIGNAL, AND THE UNCALIBRATED 0Z GEFS AND ECENS ODDS TILT TO
BELOW-NORMAL PRECIPITATION FOR NON-COASTAL AREAS DURING WEEK-2. THEREFORE, THE
SLIGHT RISK OF HEAVY PRECIPITATION IS SCOPED ONLY TO IMMEDIATE COASTAL AREAS OF
THE MID-ATLANTIC AND SOUTHEAST, AS WELL AS FLORIDA, FOR OCT 6-8. THE SLIGHT
RISK FOR HIGH WINDS IS DISCONTINUED DUE TO DECREASING SIGNALS IN THE ECENS PET
AND A PREDICTED WEAKENING OF THE PRESSURE GRADIENT. INTERESTS ACROSS THE
EASTERN CAROLINAS AND COASTAL SOUTHEAST SHOULD MONITOR UPDATES FROM NHC, WPC,
AND THEIR LOCAL WEATHER FORECAST OFFICES (WFOS) REGARDING THE CONTINUED
EVOLUTION AND IMPACTS FROM TROPICAL STORM IMELDA DURING THE NEXT WEEK.
THE 0Z ECENS AND GEFS INDICATE POSITIVE 500-HPA HEIGHT ANOMALIES OVER MUCH OF
THE CENTRAL AND NORTHEASTERN CONUS DURING WEEK-2 TIED TO INITIAL RIDGING OVER
EASTERN CANADA, FOLLOWED BY ADDITIONAL RIDGING DEVELOPING ACROSS THE
NORTH-CENTRAL CONUS TOWARD THE MIDDLE OF THE PERIOD. THIS PATTERN SUPPORTS
ABOVE-NORMAL TEMPERATURES OVER MUCH OF THE CONUS, WITH THE LARGEST POSITIVE
TEMPERATURE ANOMALIES (EXCEEDING +10 DEG F) FAVORED ACROSS THE UPPER MIDWEST
AND GREAT LAKES. WHILE THIS WOULD BE CONSIDERED UNSEASONABLY WARM BY FALL
STANDARDS, IT IS NOT HAZARDOUS WITH TEMPERATURES GENERALLY IN THE 60S AND 70S
DEG F. ALTHOUGH TEMPERATURES ARE LIKELY TO BE WARMER FARTHER SOUTH ACROSS THE
SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY (80S TO LOW 90S DEG F), HEAT RISK
GUIDANCE IS UNSUPPORTIVE OF HEAT INDICES EXCEEDING HAZARD CRITERIA, PRECLUDING
ANY TEMPERATURE RELATED HAZARDS.
LATE IN WEEK-1, SURFACE LOW PRESSURE IS FORECAST TO TRACK ACROSS THE BERING SEA
INTO WESTERN ALASKA. THE STRONGEST ONSHORE FLOW IS PREDICTED TO BE ALONG THE
SOUTHERN COAST OF THE STATE. HOWEVER, THE HIGHEST 24-HOUR PRECIPITATION TOTALS
IN THE 0Z ECENS OCCURS ON DAY-7 AND BEGINS TO DECREASE ON DAY-8. THE SIGNAL IN
THE 0Z GEFS IS ALSO COMPARATIVELY WEAKER AT THE START OF WEEK-2. THEREFORE, THE
SLIGHT RISK FOR HEAVY PRECIPITATION IS DISCONTINUED GIVEN THAT THE GREATEST
POTENTIAL IS NOW WITHIN THE WEEK-1 PERIOD. ENHANCED PRECIPITATION AND HIGHER
ELEVATION SNOW ARE ALSO POSSIBLE ACROSS PORTIONS OF WESTERN MAINLAND ALASKA,
WITH AMOUNTS LIKELY REMAINING BELOW HAZARDS THRESHOLDS.
THE 0Z ECENS AND GEFS DEPICT MORE TROUGHING ACROSS THE WESTERN CONUS EARLY IN
WEEK-2 COMPARED TO YESTERDAY, WHICH MAY BRING RELATIVELY COOLER TEMPERATURES TO
PORTIONS OF THE NORTHWEST AND GREAT BASIN. THE 0Z ECENS AND GEFS INDICATE
INCREASED WIND SPEEDS ALONG THE COAST OF CALIFORNIA AND OREGON BEGINNING LATE
IN WEEK-1 AS SURFACE PRESSURES FALL ACROSS THE WEST, AND A TIGHT GRADIENT WITH
SURFACE HIGH PRESSURE OVER THE EASTERN PACIFIC DEVELOPS. HOWEVER, THE SIGNAL
BECOMES WEAKER GOING INTO WEEK-2 PRECLUDING A RELATED HAZARD. INCREASED WINDS
ARE ALSO POSSIBLE ACROSS THE GREAT PLAINS AT THE START OF WEEK-2. WHILE
PROBABILITIES FOR WIND SPEEDS EXCEEDING 20-MPH EXCEEDS 20 PERCENT IN THE ECENS
PET, THEY FALL BELOW 20 PERCENT AT THE 25-MPH THRESHOLD. AS A RESULT, NO
RELATED WIND HAZARD IS POSTED ACROSS THE PLAINS. BOTH THE GEFS AND ECENS PETS
DEPICT AN UPTICK IN PRECIPITATION ACROSS THE PACIFIC NORTHWEST LATE IN WEEK-2,
WITH DAY 12-14 PRECIPITATION TOTALS HAVING AT LEAST A 20 PERCENT CHANCE OF
EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND 1-INCH, TIED TO TROUGHING
RELOADING ACROSS THE WEST. THESE TRENDS WILL CONTINUE TO BE MONITORED
THROUGHOUT THE WEEK.
ACROSS PORTIONS OF TEXAS AND SOUTHWESTERN LOUISIANA, PRECIPITATION DEFICITS OF
SEVERAL INCHES HAVE ACCUMULATED DURING THE PAST 30-DAYS. PERCENT-OF-NORMAL
PRECIPITATION (PNP) FALLS WITHIN THE TWO LOWEST QUARTILES (1ST THROUGH 25TH
PERCENTILES AND 26TH THROUGH 50TH PERCENTILES) OF THE CLIMATOLOGICAL
DISTRIBUTION. ABOVE-NORMAL TEMPERATURES PREDICTED FOR THE NEXT TWO WEEKS, AND
GENERALLY LITTLE OR NO PRECIPITATION INCREASES THE POTENTIAL FOR RAPID ONSET
DROUGHT (ROD) ACROSS THIS REGION.
FORECASTER: THOMAS COLLOW
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