714
FXUS21 KWNC 281926
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 28 2025
SYNOPSIS: MID-LEVEL HIGH PRESSURE IS A DOMINANT FEATURE OVER THE CONTIGUOUS
U.S. (CONUS) FOR MUCH OF THE WEEK-2 FORECAST PERIOD, RESULTING IN GENERALLY
QUIET WEATHER FROM A HAZARDS PERSPECTIVE. TEMPERATURES FOR MUCH OF THE LOWER 48
ARE LIKELY TO BE ABOVE-NORMAL, BUT MODEL GUIDANCE OFFERS LITTLE EVIDENCE OF
TEMPERATURES REACHING HAZARDOUS THRESHOLDS. MID-LEVEL LOW PRESSURE ALONG THE
WEST COAST AT THE OUTSET OF WEEK-2 IS FAVORED TO BRING ENHANCED WINDS TO MUCH
OF THE GREAT BASIN AND SOUTHERN ROCKIES. A WEAK DISTURBANCE OVER THE
U.S.-CANADA BORDER AT THE OUTSET OF WEEK-2 HAS THE POTENTIAL TO BRING PERIODS
OF HEAVY PRECIPITATION TO PORTIONS OF THE GREAT LAKES, AND THE OHIO AND
MISSISSIPPI VALLEYS, ESPECIALLY EARLY IN THE FORECAST PERIOD.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE GREAT LAKES, AND THE
OHIO AND MIDDLE AND UPPER MISSISSIPPI VALLEYS, TUE-THU, AUG 5-7.
SLIGHT RISK OF EPISODIC HIGH WINDS FOR MUCH OF THE GREAT BASIN, CENTRAL AND
SOUTHERN ROCKIES, AS WELL AS WESTERN PORTIONS OF THE CENTRAL AND SOUTHERN
PLAINS, TUE-THU, AUG 5-7.
SLIGHT RISK OF HIGH WINDS FOR COASTAL CALIFORNIA FROM POINT CONCEPTION TO CAPE
MENDOCINO, TUE-MON, AUG 5-11.
DETAILED SUMMARY
FOR THURSDAY JULY 31 - MONDAY AUGUST 04:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY AUGUST 05 - MONDAY AUGUST 11: ENSEMBLE SOLUTIONS FOR 500-HPA HEIGHT
ANOMALIES FROM THE GEFS, ECMWF, AND CMCE ALL INDICATE WIDESPREAD RIDGING OVER
THE LOWER 48 FOR MOST OF THE FORECAST PERIOD, USHERING IN A PERIOD OF
RELATIVELY QUIET, IF WARMER THAN AVERAGE, WEATHER. AT THE OUTSET OF WEEK-2 A
WEAKENING TROUGH OVER THE WEST COAST IS FAVORED TO ENHANCE DAYTIME WINDS FOR
MUCH OF THE HIGHER ELEVATIONS IN THE WESTERN CONUS. A SLIGHT RISK OF HIGH WINDS
IS POSTED FOR MUCH OF THE GREAT BASIN, CENTRAL AND SOUTHERN ROCKIES, AS WELL AS
WESTERN PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS FOR AUG 5-7, WHERE THE
ECMWF PROBABILISTIC EXTREMES TOOL (PET) INDICATES AT LEAST A 20% CHANCE OF
3-DAY MAXIMUM WINDS TO EXCEED THE 85TH PERCENTILE. THE GEFS PET IS LESS
BULLISH, CONFINING ENHANCED WINDS PRIMARILY TO THE NORTHERN GREAT BASIN, BUT
RAW PROBABILISTIC GUIDANCE FROM BOTH MODEL ENSEMBLES INDICATE VERY HIGH
LIKELIHOOD OF DAYTIME WINDS EXCEEDING 10 KTS FOR THE SAME PERIOD OF TIME, AFTER
WHICH THIS THRESHOLD BECOMES LESS LIKELY. THE REGION IS ALSO FAVORED FOR
BELOW-NORMAL PRECIPITATION AND ABOVE NORMAL TEMPERATURES, ENHANCING THE
POTENTIAL FOR INITIATION AND GROWTH OF WILDFIRES.
THE SUMMER SUB-TROPICAL SURFACE HIGH OVER THE NORTH PACIFIC HAS BEEN QUITE
STRONG RECENTLY, WHICH HAS HAD THE POTENTIAL OF ENHANCING COASTAL WINDS TYPICAL
FOR THIS TIME OF YEAR. MODEL GUIDANCE FOR WEEK-2 INDICATES THAT THIS
ENHANCEMENT IS LIKELY THROUGHOUT THE FORECAST PERIOD. THE GEFS AND ECMWF PETS
BOTH INDICATE VERY HIGH PROBABILITIES (>60%) OF WINDS NEAR THE CALIFORNIA COAST
EXCEEDING 25 MPH THROUGHOUT WEEK-2, THEREFORE A SLIGHT RISK OF HIGH WINDS IS
POSTED FOR COASTAL PORTIONS OF CALIFORNIA FROM POINT CONCEPTION TO CAPE
MENDOCINO FOR ALL OF WEEK-2, AUG 5-11.
WEAK SURFACE LOW PRESSURE IS FAVORED ALONG THE U.S.-CANADA BORDER FOR MUCH OF
WEEK-2, AND MODELS ARE DEPICTING ENHANCED PRECIPITATION FOR A GOOD PORTION OF
THE MIDWEST. THE GEFS AND ECMWF PETS BOTH INDICATE AT LEAST A 20% PROBABILITY
OF 3-DAY PRECIPITATION TOTALS TO EXCEED THE 85TH PERCENTILE AND AT LEAST 0.75
INCHES FOR AUG 5-7, THEREFORE A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED
FOR PORTIONS OF THE MIDDLE AND UPPER MISSISSIPPI VALLEY, GREAT LAKES, AND OHIO
VALLEY FOR THESE DAYS. MODEL SOLUTIONS DIVERGE SOMEWHAT AFTER THE 7TH, BUT
THERE ARE SOME INDICATIONS THAT THIS EVENT MIGHT EXTEND FURTHER SO THE
SITUATION WILL BE CLOSELY MONITORED.
WIDESPREAD UPPER-LEVEL RIDGING OVER THE CONUS FAVORS ABOVE-NORMAL TEMPERATURES
FOR MOST OF THE LOWER 48. THE GEFS AND ECMWF PETS BOTH INDICATE AT LEAST A 20%
CHANCE OF MAXIMUM TEMPERATURE EXCEEDING THE 85TH PERCENTILE FOR MANY PORTIONS
OF THE CONUS, AND THE NORTHEAST U.S., SOUTHERN PLAINS, DESERT SOUTHWEST AND
GREAT BASIN ARE ALL HIGHLIGHTED AS AREAS OF INTEREST. HOWEVER, IN ALL CASES,
TEMPERATURES ARE NOT EXPECTED TO REACH HAZARDOUS THRESHOLDS SO NO HAZARDS ARE
POSTED AT THIS TIME, BUT THE SITUATION WILL BE MONITORED CLOSELY.
FORECASTER: DANNY BARANDIARAN
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