879
FXUS21 KWNC 011839
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 01 2026
SYNOPSIS: REBUILDING MID-LEVEL HIGH PRESSURE OVER PARTS OF THE WESTERN AND
CENTRAL CONTIGUOUS U.S. (CONUS) SUPPORTS ABOVE-NORMAL SUMMERTIME TEMPERATURES
WITH AN INCREASED HEAT RISK EXTENDING FROM THE SOUTHWESTERN U.S. INTO THE UPPER
MIDWEST DURING WEEK-2. FURTHER SOUTH, ENHANCED SUBTROPICAL HIGH PRESSURE ALSO
FAVORS THE POTENTIAL FOR EXTREME HEAT CONDITIONS FOR PARTS OF EASTERN GULF OF
AMERICA COAST DURING THE PERIOD. SURFACE LOW DEVELOPMENT AND AN ACCOMPANYING
HEAVY PRECIPITATION RISK REMAINS FAVORED OVER PARTS OF THE SOUTHEAST AND
MID-ATLANTIC. OVER THE WEST COAST, STRENGTHENING PRESSURE GRADIENTS FAVORED
LEADS TO INCREASED CHANCES FOR EPISODES OF HIGH WINDS ACROSS THE PACIFIC
NORTHWEST AND CALIFORNIA FOR MUCH OF THE PERIOD.
HAZARDS
SLIGHT RISK OF EXTREME HEAT ACROSS MUCH OF THE GREAT BASIN, NORTHERN
INTERMOUNTAIN, ROCKIES, SOUTHWEST, AND GREAT PLAINS, THU-WED, JUL 9-15.
SLIGHT RISK OF EXTREME HEAT FOR THE EASTERN GULF COAST AND FLORIDA PENINSULA,
THU-WED, JUL 9-15.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE MID-ATLANTIC AND THE
SOUTHEAST, THU-SAT, JUL 9-11.
SLIGHT RISK OF EPISODIC HIGH WINDS FOR PORTIONS OF CALIFORNIA AND THE PACIFIC
NORTHWEST, THU-WED, JUL 9-15.
DETAILED SUMMARY
FOR SATURDAY JULY 04 - WEDNESDAY JULY 08:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY JULY 09 - WEDNESDAY JULY 15: FOLLOWING A SIGNIFICANT HEAT EVENT
THAT IS FORECAST TO AFFECT MUCH OF THE CENTRAL AND EASTERN CONUS DURING WEEK-1,
MODELS HAVE BEEN CONSISTENT IN FAVORING A RETROGRADING 500-HPA RIDGE BY EARLY
NEXT WEEK. ANOMALOUSLY WARM TEMPERATURES AND POTENTIAL EXTREME HEAT CONDITIONS
ARE MAINLY FAVORED ALONG A MEAN RIDGE AXIS THAT BECOME ESTABLISHED OVER THE
WESTERN AND NORTHCENTRAL CONUS TOWARDS THE MIDDLE OF NEXT WEEK. HEADING INTO
THE WEEK-2 PERIOD (JUL 9-10), MUCH OF THE RIDGING IS FAVORED TO DEAMPLIFY,
WHERE BOTH THE GEFS AND ECMWF ENSEMBLES SHOW A WEAKER MEAN SOLUTION OF THIS
MID-LEVEL FEATURE COMPARED TO YESTERDAY. HOWEVER, THIS DEAMPLIFICATION LOOKS
TO ONLY BE TEMPORARY, AS THERE IS GROWING MODEL SUPPORT FOR A REBUILDING RIDGE
ACROSS THE INTERIOR WEST TOWARDS THE MIDDLE OF WEEK-2. THE ECMWF APPEARS MOST
BULLISH WITH THIS RESTRENGTHENING, AND FEATURES A MEAN 597 DM HEIGHT FIELD
PEAKING OVER THE EASTERN FOUR CORNERS ON DAYS 12-13 (JUL 13-14). THE PATTERN
REAMPLIFICATION AND POTENTIAL RENEWAL OF HEAT IS NOTEWORTHY, AS NOT OFTEN
ANOMALIES OF THIS MAGNITUDE ARE EVIDENT AT THESE LONGER LEADS DUE TO ENSEMBLE
SPREAD. ACROSS THE LOWER LATITUDES, ENHANCED SUBTROPICAL RIDGING OVER THE GULF
OF AMERICA AND WESTERN ATLANTIC LOOKS TO REMAIN A FACTOR IN THE OUTLOOK.
CONSISTENT WITH THE EVOLUTION OF MID-LEVEL RIDGE FURTHER NORTH OVER THE
INTERIOR WEST, A REAMPLIFICATION IS DEPICTED IN THE ENSEMBLE GUIDANCE WHERE
COUPLED WITH ANOMALOUSLY WARM SEA SURFACE TEMPERATURES IN THE EASTERN GULF,
THIS FAVORS MORE PERSISTENCE OF ABOVE-NORMAL TEMPERATURES AND HEAT RISKS OVER
PARTS OF THE SOUTHEAST THROUGHOUT WEEK-2.
DUE TO THE VARYING STRENGTH OF THE 500-HPA RIDGE FAVORED DURING THE PERIOD,
THERE IS MORE RELIANCE ON THE RAW TEMPERATURE TOOLS IN THE UPDATED OUTLOOK, AS
THESE TOOLS APPEAR TO SHOW A MORE CONSISTENT RESPONSE TO THE EVOLVING PATTERN
ALOFT COMPARED TO THE CALIBRATED GUIDANCE. WITH THE RIDGE AXIS REMAINING IN A
FAIRLY STABLE POSITION DURING THE PERIOD, A SLIGHT RISK OF EXTREME HEAT REMAINS
POSTED FROM THE SOUTHWESTERN CONUS NORTHEASTWARD TO THE UPPER MIDWEST BUT IS
NOW VALID FOR ALL OF WEEK-2 TO CAPTURE FLUCTUATIONS IN ANOMALOUS TEMPERATURES
AND ACCOMPANYING HEAT RISKS. RELATIVELY COOLER DAYTIME TEMPERATURES AND
DECREASED HEAT RISKS ARE POSSIBLE WITHIN THE HIGHLIGHTED AREA AS THE RIDGE
DEAMPLIFIES EARLY IN THE PERIOD, WHICH IS BEST SUPPORTED BY LOW CHANCES FOR
DAYTIME TEMPERATURES EXCEEDING THE 85TH PERCENTILE IN THE ECMWF PET. OVER TIME,
BOTH THE GEFS AND ECMWF PETS COME INTO BETTER AGREEMENT FAVORING REMERGING WARM
SIGNALS WITH 20-30% CHANCES OF MAXIMUM TEMPERATURE EXCEEDING THE 85TH
PERCENTILE OVER THE INTERIOR WEST, AS WELL AS IN THE RAW TOOLS DEPICTING HIGHER
TEMPERATURE EXCEEDANCE SIGNALS BY DAYS 10 AND 11 (JUL 11-12) WITH PROBABILITIES
SUPPORTIVE OF THE SLIGHT RISK. SHOULD THE MODELS SHOW GOOD CONTINUITY IN
MAINTAINING THE VERY STRONG MID-LEVEL HEIGHT DEPARTURES (AS ADVERTISED BY THE
ECMWF LATE IN WEEK-2) OVER THE INTERIOR WEST IN THE COMING DAYS, HIGHER RISK
DESIGNATIONS OF EXTREME HEAT (INCLUDING MODERATE AND HIGH RISKS) ARE LIKELY TO
BE ADDED IN UPCOMING OUTLOOKS. THE POTENTIAL FOR A HIGHER RISK DESIGNATION IS
ALSO SUPPORTED BY MODELS TENDENCY TO UNDERESTIMATE HIGH TEMPERATURES OVER AREAS
WITH ANTECEDENT DRYNESS, WHERE ACTUAL TEMPERATURES COULD END UP BEING HIGHER
THAN FAVORED.
TIED TO THE MORE PERSISTENT ENHANCED SUBTROPICAL RIDGING FAVORED OVER THE GULF
AND WESTERN ATLANTIC, A SLIGHT RISK OF EXTREME HEAT IS ALSO POSTED OVER THE
EASTERN GULF COAST AND FLORIDA PENINSULA AND NOW VALID FOR ALL OF WEEK-2. THIS
RISK IS SUPPORTED BY THE DETERMINISTIC NBM DEPICTING APPARENT TEMPERATURES
ABOVE 100 DEG F LATE NEXT WEEK, AND THE PETS INDICATING INCREASED CHANCES FOR
DAYTIME TEMPERATURES EXCEEDING THE 85TH PERCENTILE THROUGHOUT WEEK-2. VERY
WARM SEA SURFACE TEMPERATURES IN THE EASTERN GULF, WITH ANOMALIES REGISTERING
UPWARDS OF 1.5 TO 2 DEG C ABOVE NORMAL. THE NBM ALSO CONTINUES TO SHOW A NUMBER
OF LOCATIONS WITH VERY WARM NIGHTTIME LOWS APPROACHING AND/OR BREAKING RECORDS
ALONG THE GULF COAST THROUGH LATE NEXT WEEK.
DOWNSTREAM OF THE ANOMALOUS RIDGING OVER THE WESTERN AND CENTRAL CONUS, MORE
MID-LEVEL TROUGHING IS FAVORED OVER THE EASTERN U.S. WHERE THERE CONTINUES TO
BE ENSEMBLE SUPPORT FOR SURFACE LOW DEVELOPMENT POTENTIALLY AFFECTING PARTS OF
THE SOUTHEAST AND MID-ATLANTIC. SIMILAR TO YESTERDAY, THERE ARE SEVERAL LOW
MEMBERS FEATURED OVER THE LOWER EASTERN SEABOARD AND JUST OFFSHORE IN WESTERN
ATLANTIC WHICH ARE ALSO REFLECTED IN PROBABILISTIC ECMWF AND GOOGLE AI TROPICAL
CYCLONE DEVELOPMENT TOOLS. AS IS OFTEN THE CASE WITH THESE TYPES OF LOWS
FORMING NEAR SHORE, THERE IS HIGH UNCERTAINTY AS TO WHETHER ANY LOW THAT
DEVELOPS WILL ACQUIRE TROPICAL CHARACTERISTICS, BUT SUCH A REALIZATION CANNOT
BE RULED OUT. REGARDLESS, ENHANCED PRECIPITATION IS FAVORED TO ACCOMPANY ANY
DEVELOPING SURFACE LOW AS PETS AND RAW TOOLS CONTINUE TO SHOW INCREASED CHANCES
FOR 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE AND 1 INCH EARLY IN WEEK-2.
THEREFORE, A SLIGHT RISK OF HEAVY PRECIPITATION REMAINS ISSUED FOR PARTS OF THE
SOUTHEAST AND LOWER MID-ATLANTIC, JUL 9-11. WITHIN THE HIGHLIGHTED SLIGHT RISK
AREA, ANY ENHANCED PRECIPITATION IS EXPECTED TO BE WELCOME FOLLOWING THE HEAT
FAVORED DURING WEEK-1, THOUGH LOCALIZED URBAN FLOODING IS POSSIBLE. BASED ON
THE PETS, ELEVATED WIND SPEEDS ARE POSSIBLE ALONG THE COASTAL CAROLINAS AND
GEORGIA, HOWEVER THE STRONGEST WINDS ARE FAVORED OFFSHORE AND NO CORRESPONDING
WIND HAZARD IS POSTED.
ACROSS THE DESERT SOUTHWEST, THE ECMWF PET SHOWS A NORTHWARD EXTENSION OF THE
WET SIGNAL INTO THE GREAT BASIN, WHEREAS THE GEFS PETS MAINTAINS A MORE
SUPPRESSED SIGNAL OVER WESTERN MEXICO TOWARDS THE MIDDLE OF WEEK-2. DESPITE
THIS DIFFERENCE, THE INCREASE IN PERCENTILE SPACE WELL ALIGNS WITH THE TIME
WHERE MODELS FAVOR THE REAMPLIFICATION OF THE RIDGE, AND SUGGESTS A MORE ACTIVE
MONSOONAL CIRCULATION LATER IN WEEK-2. DUE TO THE CONTINUED LACK OF SUPPORT IN
THE RAW TOOLS WITH BOTH DAILY AND 3-DAY MEAN TOTALS REMAINING LOW, NO
CORRESPONDING PRECIPITATION HAZARDS ARE POSTED. LOCALIZED THUNDERSTORMS ARE
STILL POSSIBLE AND THIS AREA WILL CONTINUE TO BE MONITORED WITH ENSEMBLE
GUIDANCE INDICATING PRECIPITABLE WATER INCREASING DURING THE WEEK-2 PERIOD.
SURFACE HIGH PRESSURE OFF THE WEST COAST ALONG WITH THERMALLY INDUCED LOW
PRESSURE OVER THE GREAT BASIN AND DESERT SOUTHWEST INCREASE CHANCES FOR
EPISODES OF HIGH WINDS DURING WEEK-2. THE GEFS AND ECMWF PETS CONTINUE TO
INDICATE AT LEAST A 20 PERCENT CHANCE OF WIND SPEEDS EXCEEDING THE 85TH
CLIMATOLOGICAL PERCENTILE. THEREFORE, A SLIGHT RISK OF HIGH WINDS REMAINS
POSTED ACROSS THIS REGION, JUL 9-15. IT SHOULD BE NOTED THAT ANY SUBSTANTIAL
INCREASE IN MONSOONAL MOISTURE AND PRECIPITATION WILL BRING COOLER
TEMPERATURES, WHICH IS LIKELY TO BREAK DOWN THE THERMAL LOW PRESSURE AND WEAKEN
THIS HIGH WIND POTENTIAL DURING THE PERIOD.
FORECASTER: NICK NOVELLA
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