760
FXUS21 KWNC 191802
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 19 2025
SYNOPSIS: MODEL ENSEMBLES FAVOR A TRANSITION FROM AN AMPLIFIED WAVE TRAIN IN
MID-LEVEL PRESSURE TO A MORE FLATTENED PATTERN, RESULTING IN FEW CONCERNS FROM
A HAZARDOUS WEATHER PERSPECTIVE. EARLY IN WEEK-2 MID-LEVEL LOW PRESSURE OVER
THE NORTH PACIFIC MAY ENHANCE SURFACE WINDS ALONG PORTIONS OF THE CALIFORNIA
COAST.
HAZARDS
SLIGHT RISK OF EPISODIC HIGH WINDS FOR COASTAL PORTIONS OF CALIFORNIA FROM CAPE
MENDOCINO TO POINT CONCEPTION, SAT-MON, SEP 27-29.
DETAILED SUMMARY
FOR MONDAY SEPTEMBER 22 - FRIDAY SEPTEMBER 26:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY SEPTEMBER 27 - FRIDAY OCTOBER 03: TODAY’S MODEL SOLUTIONS FOR
500-HPA HEIGHTS INDICATE A TRANSITION AWAY FROM AN AMPLIFIED WAVE TRAIN
STRETCHING OVER NORTH AMERICA TO A MUCH MORE ZONAL PATTERN DURING THE WEEK-2
PERIOD, RESULTING IN RELATIVELY TRANQUIL WEATHER WITH FEW CONCERNS WITH RESPECT
TO THE POTENTIAL FOR HAZARDOUS WEATHER OVER THE CONTIGUOUS U.S. (CONUS). AT THE
OUTSET OF WEEK-2 GUIDANCE CONTINUES TO DEPICT A FAIRLY DEEP TROUGH OFF THE WEST
COAST. THIS PATTERN, IN ADDITION TO PREDICTED SURFACE HIGH PRESSURE NEAR THE
WEST COAST AND ADJACENT SURFACE LOW PRESSURE OVER WEST COAST STATES, MAY RESULT
IN A TIGHT PRESSURE GRADIENT AT THE SURFACE AND INCREASED LIKELIHOOD FOR HIGH
WINDS ACROSS THE WEST COAST. A SLIGHT RISK OF EPISODIC HIGH WINDS IS
HIGHLIGHTED FOR COASTAL PORTIONS OF CALIFORNIA BETWEEN CAPE MENDOCINO AND POINT
CONCEPTION FOR SEP 27-29, WHERE PROBABILISTIC EXTREME TOOLS (PETS) INDICATE AT
LEAST A 20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH PERCENTILE AND 25 MPH AND
ENSEMBLE MEAN WIND SPEED FROM BOTH THE GEFS AND ECMWF INDICATE ENHANCED WINDS
FOR MUCH OF THE CALIFORNIA COAST EARLY IN WEEK-2.
IN ADDITION TO ENHANCED WINDS, MODELS DEPICT SIGNIFICANT MOISTURE TRANSPORT
INTO THE PACIFIC NORTHWEST AS THIS TROUGH MOVES INTO THE INTERIOR WEST. THIS IS
LIKELY TO RESULT IN PERIODS OF ENHANCED PRECIPITATION FOR MUCH OF THE
NORTHWESTERN CONUS THROUGH THE MIDDLE OF WEEK-2. WHILE LOW ELEVATION
ACCUMULATIONS (I.E. RAIN) ARE NOT LIKELY TO REACH HAZARDOUS THRESHOLDS, MODEL
SOLUTIONS HAD BEEN INDICATING THE POTENTIAL OF HEAVY SNOW ACROSS HIGH ELEVATION
AREAS OF THE NORTHERN CASCADES AND ROCKIES AS A COLDER AIRMASS MOVES IN WITH
THE TROUGH. TODAY’S MODEL SOLUTIONS ARE LESS BULLISH WITH REGARD TO
SUFFICIENTLY LOW TEMPERATURES FOR SNOW THEREFORE NO ASSOCIATED HAZARD IS POSTED
AT THIS TIME.
FORECASTER: DANNY BARANDIARAN
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