449
FXUS21 KWNC 231929
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 23 2025
SYNOPSIS: FAIRLY HIGH UNCERTAINTY CONTINUES TO MAKE THE WEEK-2 U.S. HAZARDS
OUTLOOK CHALLENGING THIS WEEK. THERE ARE SIGNIFICANT VARIATIONS IN THE TIMING
AND AMPLITUDE OF MID-LEVEL CIRCULATION FEATURES AND THE PREDOMINANCE OF FAST
WESTERLY FLOW. AN ACTIVE WEATHER PATTERN ACROSS THE GULF OF ALASKA SUPPORTS A
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF SOUTHEAST ALASKA DURING THE
SECOND HALF OF THE FORECAST PERIOD. THE TROPICAL ATLANTIC REMAINS ACTIVE, WITH
THE NATIONAL HURRICANE CENTER MONITORING THE POTENTIAL FOR TWO TROPICAL SYSTEMS
TO DEVELOP OVER THE WESTERN ATLANTIC WITHIN THE NEXT 7 DAYS. IT IS CURRENTLY
UNCLEAR AS TO THE EXACT TRACK AND INTENSITY OF EACH OF THESE TROPICAL SYSTEMS,
AND WHETHER OR NOT THEY WILL REMAIN OFFSHORE OR APPROACH THE MID-ATLANTIC COAST.
HAZARDS
SLIGHT RISK OF HIGH WINDS ALONG THE EAST COAST, WED-THU, OCT 1-2.
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE ALASKA PANHANDLE, SAT-TUE, OCT 4-7.
DETAILED SUMMARY
FOR FRIDAY SEPTEMBER 26 - TUESDAY SEPTEMBER 30:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY OCTOBER 01 - TUESDAY OCTOBER 07: THE LARGE-SCALE CIRCULATION
PATTERN PREDICTED BY THE DYNAMICAL MODELS FOR THE WEEK-2 PERIOD IS
CHARACTERIZED BY SHORTWAVE TROUGHS MOVING ACROSS THE BERING SEA AND GULF OF
ALASKA, AND A BROAD FLAT RIDGE OVER CANADA ACCOMPANIED BY MAXIMUM POSITIVE
HEIGHT ANOMALIES ON THE ORDER OF 60-120 METERS ABOVE AVERAGE. RELATIVELY FAST
WESTERLY FLOW IS PREDICTED OVER MOST OF THE LOWER 48 STATES BY THE ECENS AND
GEFS ENSEMBLE MEAN SOLUTIONS.
SURFACE LOW PRESSURE CENTERED IN THE VICINITY OF THE ALASKA
PENINSULA/NORTHWESTERN GULF OF ALASKA SUPPORTS ONSHORE FLOW ACROSS SOUTHEAST
ALASKA AND PORTIONS OF SOUTH-CENTRAL ALASKA DURING THE PERIOD. THE GEFS
PRECIPITATION PROBABILISTIC EXTREMES TOOL (PET) PREDICTS 2-3 INCHES OF
PRECIPITATION FROM ABOUT YAKUTAT SOUTHWARD TO KETCHIKAN, WHERE A SLIGHT RISK OF
HEAVY PRECIPITATION HAS BEEN POSTED FROM OCT 4-7. FARTHER DOWN THE WEST COAST,
THE PACIFIC NORTHWEST IS FORECAST BY CALIBRATED AND UNCALIBRATED TOOLS TO
RECEIVE 1.0-1.5 INCHES OF PRECIPITATION, BUT THIS IS NOT UNUSUAL FOR THIS TIME
OF YEAR. ANOTHER AREA THAT IS BEING MONITORED FOR THE POTENTIAL OF HEAVY
PRECIPITATION IS THE MID-ATLANTIC REGION, WHICH MAY SEE THE APPROACH OF ONE OR
TWO TROPICAL SYSTEMS FROM THE WESTERN ATLANTIC LATER IN WEEK-1 OR EARLY WEEK-2.
AT THIS TIME, IT IS UNCERTAIN AS TO WHETHER THE HEAVIEST PRECIPITATION WILL
AFFECT NORTHERN PORTIONS OF THE MID-ATLANTIC (ECENS) OR SOUTHERN PORTIONS OF
THE MID-ATLANTIC (GEFS), PRECLUDING ANY DESIGNATED HEAVY PRECIPITATION SHAPE IN
THIS REGION. HOWEVER, A SLIGHT RISK OF HIGH WINDS IS POSTED FROM NORTH CAROLINA
TO LONG ISLAND, NY, ON OCT 1-2, AS AN ENHANCED PRESSURE GRADIENT RESULTS FROM
THE GRADUAL CONVERGENCE OF A TROPICAL SYSTEM FROM THE SOUTHEAST, AND SURFACE
HIGH PRESSURE OVER THE NORTHEAST. WINDS OF 20-25 MPH ARE FAVORED AT THIS TIME,
THOUGH DEPENDENT OF COURSE ON HOW INTENSE THE TROPICAL SYSTEMS ARE AS THEY
APPROACH THE REGION FROM THE SOUTHEAST.
POSITIVE 500-HPA HEIGHT DEPARTURES AND FAST WESTERLY FLOW OVER MUCH OF THE
CONTIGUOUS U.S. (CONUS) SUPPORTS ABOVE-NORMAL TEMPERATURES DURING WEEK-2.
HOWEVER, THE ACTUAL TEMPERATURES FORECAST OVER THE NORTH-CENTRAL STATES AND THE
SOUTHERN CONUS ARE NOT EXPECTED TO REACH HAZARDS CRITERIA, PRECLUDING THE
DESIGNATION OF A HEAT HAZARD. THIS IS COMMONLY OBSERVED DURING THE SHOULDER
SEASONS, AND SIGNIFIES THE GRADUAL WANING OF ONE SEASON AND THE GRADUAL WAXING
OF ANOTHER.
FORECASTER: ANTHONY ARTUSA
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