250
FXUS21 KWNC 241820
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 24 2025
SYNOPSIS: DEVELOPING MID-LEVEL LOW PRESSURE OVER EASTERN NORTH AMERICA IS
EXPECTED TO BRING A WELCOMED COOLDOWN FOR MANY PARTS OF THE CENTRAL AND EASTERN
CONTIGUOUS U.S. (CONUS) EXPERIENCING EXTREME HEAT CONDITIONS, THOUGH A
LINGERING THREAT OF HEAT IS EXPECTED OVER SOUTHEASTERN CONUS BY LATE NEXT WEEK.
POTENTIALLY STALLED FRONTAL ACTIVITY FAVORED OVER THE LOWER EASTERN SEABOARD
SUPPORTS AN INCREASED RISK FOR HEAVY PRECIPITATION OVER THE GULF STATES AND
INTO THE MID-ATLANTIC. ASSOCIATED WITH MID-LEVEL HIGH (LOW) PRESSURE FAVORED
OVER THE GREAT PLAINS (WEST COAST), PERIODS OF ELEVATED WINDS ARE POSSIBLE OVER
THE WESTERN CONUS, AS WELL AS HEAVY PRECIPITATION OVER PARTS OF THE LOWER FOUR
CORNERS, GREAT PLAINS AND MISSISSIPPI VALLEY.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PARTS OF THE COASTAL SOUTHEAST AND
MID-ATLANTIC, FRI-SUN, AUG 1-3.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE LOWER MISSISSIPPI VALLEY,
SOUTHEAST, AND MID-ATLANTIC, FRI-TUE, AUG 1-5.
SLIGHT RISK OF EXTREME HEAT FOR PARTS OF THE SOUTHERN PLAINS, LOWER MISSISSIPPI
VALLEY, AND THE SOUTHEAST, FRI, AUG 1.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS MANY PARTS OF THE GREAT PLAINS AND
MISSISSIPPI VALLEY, FRI-MON, AUG 1- 4.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE DESERT SOUTHWEST, FRI-SUN,
AUG 1-3.
SLIGHT RISK OF HIGH WINDS FOR MANY PARTS OF THE WESTERN CONUS, FRI-MON, AUG 1-4.
DETAILED SUMMARY
FOR SUNDAY JULY 27 - THURSDAY JULY 31:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY AUGUST 01 - THURSDAY AUGUST 07: BY THE OUTSET OF WEEK-2, THERE IS
GOOD AGREEMENT BETWEEN THE 0Z GEFS AND ECMWF ENSEMBLE MEAN 500-HPA HEIGHT
FORECASTS FAVORING A FAIRLY STRONG ANOMALOUS RIDGE CENTER OVER CENTRAL CANADA,
AND A PAIR OF TROUGHS OVERSPREADING THE EASTERN NORTH AMERICA AND ACROSS THE
NORTHEASTERN PACIFIC. CONSISTENT WITH PREVIOUS GUIDANCE, THIS FORMER TROUGHING
FEATURE LOOKS TO BRING A WELCOMED COOLDOWN TO THE EXTREME HEAT CONDITIONS BEING
FELT DURING WEEK-1, AND LIKELY KEEP ANY RENEWED HEAT RISKS AT BAY MAINLY EAST
OF THE ROCKIES INTO EARLY AUGUST. WITH A MEAN SURFACE FRONTAL BOUNDARY FAVORED
TO BE POSITIONED NEAR THE OHIO AND TENNESSEE VALLEY LATE NEXT WEEK, PORTIONS OF
THE LOWER MISSISSIPPI VALLEY AND THE SOUTHEAST MAY CONTINUE TO EXPERIENCE
EXTREME HEAT CONDITIONS BEFORE THE TEMPERATURES GRADUALLY MODERATE. THIS IS
REFLECTED IN THE PROBABILISTIC EXTREME TOOLS (PETS), AND A SLIGHT RISK OF
EXTREME HEAT REMAINS POSTED AND VALID THROUGH AUG 1 WITH MUCH OF ITS COVERAGE
REMOVED FROM THE SOUTHERN PLAINS BASED ON COOLER TEMPERATURES FAVORED IN THE
ENSEMBLES OVER TEXAS. LATER IN THE PERIOD, ENSEMBLES CONTINUE TO POINT TO THE
MEAN RIDGE RETROGRADING INTO THE INTERIOR WEST ALONG WITH A DEAMPLIFICATION OF
THE MEAN TROUGH OVER THE NORTHEASTERN PACIFIC. WHILE THE ECMWF HAS BECOME
BETTER ALIGNED WITH THE GEFS IN ITS DEPICTION OF A WARMING RESPONSE OVER THE
WESTERN CONUS, HEAT SIGNALS IN BOTH PETS REMAIN FAIRLY MODEST IN THE LATEST
GUIDANCE. AS A RESULT, NO ADDITIONAL HEAT HAZARDS ARE INCLUDED IN THE OUTLOOK,
BUT THE POTENTIAL WILL CONTINUE TO BE MONITORED THIS WEEK.
TIED TO THE AFOREMENTIONED FRONTAL BOUNDARY OVER THE EASTERN CONUS, ENSEMBLES
CONTINUE TO FAVOR THIS SURFACE FEATURE BECOMING QUASI-STATIONARY OVER THE
SOUTHEASTERN CONUS, WHICH COULD BRING A PROLONGED PERIOD OF ENHANCED
PRECIPITATION TO PORTIONS OF THE LOWER EASTERN SEABOARD. THERE CONTINUES TO BE
GOOD AGREEMENT IN THE PETS INDICATING AT 20-30% CHANCES FOR 3-DAY AMOUNTS
EXCEEDING THE 85TH PERCENTILE AND 1 INCH, WHERE NOTABLY, THE UNCALIBRATED ECMWF
DEPICTS A LARGER AREA ONSHORE WITH HIGHER CHANCES (40-60%) FOR 3-DAY AMOUNTS
EXCEEDING AN INCH RELATIVE TO YESTERDAY. DUE TO THIS UPTICK IN POTENTIAL, AND
BETTER AGREEMENT IN REGARDS TO THE EVOLUTION OF THIS SURFACE FEATURE, A
MODERATE RISK OF HEAVY PRECIPITATION IS ISSUED FROM COASTAL GEORGIA NORTHWARD
TO THE DELMARVA REGION OF THE MID-ATLANTIC FOR AUG 1-3. A CORRESPONDING SLIGHT
RISK AREA REMAINS POSTED FOR BROADER AREA, AND IS EXTENDED THROUGH AUG 5 BASED
ON THE PERSISTENCE OF SIGNALS IN THE UPDATED RAW AND CALIBRATED TOOLS. WITH
SOILS EXPECTED TO BECOME DRIER ASSOCIATED WITH THE HEAT EVENT FAVORED ACROSS
PARTS OF THE SOUTHEASTERN CONUS DURING WEEK-1, URBAN FLASH FLOODING IS STILL
POSSIBLE WITH THE HIGHLIGHTED MODERATE RISK AREA. CONSISTENT WITH RECENT
RAINFALL EVENTS WITH THIS SYNOPTIC SETUP, ADDITIONAL SURFACE LOW FORMATION
REMAINS POSSIBLE ALONG A STALLED FRONTAL BOUNDARY, WHICH COULD GAIN TROPICAL
CHARACTERISTICS SHOULD ANY DEVELOPMENT OCCUR OFFSHORE AND THIS POTENTIAL WILL
CONTINUE TO BE MONITORED IN UPCOMING OUTLOOKS.
ALONG THE NORTHERN PERIPHERY OF THE MEAN 500-HPA RIDGE OVER THE CENTRAL CONUS,
EPISODIC SHOWER AND THUNDERSTORM ACTIVITY MAY BRING LOCALLY HEAVY PRECIPITATION
AMOUNTS ACROSS THE GREAT PLAINS AND PARTS OF THE MISSISSIPPI VALLEY. THIS
POTENTIAL REMAINS SUPPORTED IN THE PETS THROUGH THE MIDDLE OF WEEK-2, WITH GOOD
CONSISTENCY INDICATING INCREASED CHANCES FOR AMOUNTS EXCEEDING THREE QUARTERS
TO AN INCH ACROSS MUCH OF THE MISSOURI RIVER BASIN. THEREFORE, A SLIGHT RISK OF
HEAVY PRECIPITATION REMAINS ISSUED FOR THE CENTRAL AND NORTHERN PLAINS AND
PORTIONS OF THE WESTERN MISSISSIPPI VALLEY, VALID THROUGH AUG 4 BEFORE THE MEAN
RIDGING BEGINS TO SLIDE WESTWARD.
UPSTREAM, ENHANCED ONSHORE FLOW TIED TO A FAIRLY DEEP 500-HPA TROUGH
ENCROACHING THE WEST COAST IS ANTICIPATED TO BRING ABOVE-NORMAL PRECIPITATION
INTO MUCH OF THE NORTHWESTERN CONUS. ALTHOUGH THERE ARE ELEVATED PROBABILITIES
FOR 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE, ACTUAL TOTALS ARE EXPECTED TO
REMAIN BELOW HAZARD THRESHOLDS. PERIODS OF ELEVATED WINDS ARE HOWEVER, A
CONCERN AT OR NEAR THE BASE OF THE MEAN TROUGHING ALOFT, AND A SLIGHT RISK OF
HIGH WINDS IS POSTED (AUG 1-4) FOR MUCH OF THE WESTERN CONUS WHERE PETS
MAINTAIN INCREASED SIGNALS FOR WIND SPEEDS EXCEEDING THE 85TH PERCENTILE. THE
COMBINATION OF ELEVATED WIND SPEEDS, LOW HUMIDITY AND HIGH TEMPERATURES
INCREASES THE RISK FOR WILDFIRE ACTIVITY ACROSS PARTS OF THE WEST.
OVER THE SOUTHWESTERN CONUS, THE COMBINATION OF DEEPER TROUGHING IN THE WEST,
AS WELL AS A RENEWED POTENTIAL FOR TROPICAL CYCLONE ACTIVITY FAVORED IN THE
EASTERN PACIFIC, SUPPORTS INCREASED CHANCES FOR ABOVE-NORMAL AND POSSIBLY HEAVY
PRECIPITATION IN THE LOWER FOUR CORNERS. THE GEFS IS COMPARABLY DRIER THAN THE
ECMWF IN THE PETS, BUT THESE SYNOPTIC FACTORS, ALONG WITH INCREASED DEWPOINT
TEMPERATURES FAVORED IN THE DESERT SOUTHWEST CONTINUE TO SUPPORT A SLIGHT RISK
OF HEAVY PRECIPITATION OVER PARTS OF ARIZONA AND NEW MEXICO (AUG 1-3).
NO HAZARDS ARE ISSUED OVER ALASKA. ALTHOUGH AMPLIFIED TROUGHING IS FAVORED OVER
THE GULF OF ALASKA TO PROMOTE INCREASED WINDS AND ENHANCED PRECIPITATION
AMOUNTS OVER THE SOUTHEAST, TOOLS INDICATE AMOUNTS REMAINING BELOW HAZARD
THRESHOLDS.
FORECASTER: NICK NOVELLA
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