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
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