941
FXUS02 KWBC 251822
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
222 PM EDT SAT JUL 25 2026
VALID 12Z TUE JUL 28 2026 - 12Z SAT AUG 01 2026
..LENGTHY HEAT WAVE FOR MUCH OF THE WEST AND SOUTH
..PATTERN OVERVIEW
A STRENGTHENING UPPER RIDGE INTO THE FOUR CORNERS REGION WILL BE
THE DOMINANT FORCE IN SUSTAINING A LONG DURATION HEAT WAVE OVER THE
WESTERN AND SOUTHERN US NEXT WEEK. PLEASE SEE OUR KEY MESSAGES FOR
THIS EVENT THAT ARE LINKED ON OUR MAIN WEB PAGE. THE WESTERN
RIDGE, IN TURN, WILL FAVOR TROUGHING OVER THE NORTHEAST WITH A
MODESTLY STRONG SYSTEM TUE-WED AND SOME STORMY/RAINY WEATHER. A
WAVY FRONTAL BOUNDARY FROM THE PLAINS TO THE SOUTHEAST WILL PROMOTE
SCATTERED SHOWERS/STORMS THROUGH THE PERIOD IN ADDITION TO MAINLY
AFTERNOON STORMS OVER THE INTERMOUNTAIN WEST, THOUGH THIS WILL BE
SUPPRESSED BENEATH THE UPPER HIGH.
..GUIDANCE/PREDICTABILITY ASSESSMENT
WITH AN AMPLIFIED BUT NOT COMPLETELY BLOCKY PATTERN IN PLACE, THE
MODELS/ENSEMBLES WHERE IN VERY GOOD AGREEMENT OVERALL. A BLEND OF
THE LATEST MODELS AND ENSEMBLES PROVIDED A GOOD STARTING POINT.
THIS CONSENSUS WAS CLOSER TO THE 00Z ECMWF ENSEMBLE MEAN IN THE
NORTHEAST WITH THE LEAD SYSTEM, WITH SUPPORT FROM THE AIFS. THERE
IS ALREADY STRONG POTENTIAL FOR A CLOSED 6000M UPPER HIGH NEAR THE
UT/AZ BORDER NEXT WEEKEND.
..WEATHER/HAZARDS HIGHLIGHTS
EXTREME HEAT WILL CONTINUE TO MAKE WEATHER HEADLINES ACROSS A
LARGE EXPANSE OF THE COUNTRY GOING INTO NEXT WEEK. WIDESPREAD UPPER
90S AND LOW 100S ARE EXPECTED FROM MONTANA TO THE DAKOTAS, WHICH
IS ABOUT 10-15 DEGREES ABOVE AVERAGE. IT WILL ALSO BE VERY HOT AND
HUMID FROM TEXAS TO THE GULF COAST STATES WITH HIGHS RANGING FROM
95 TO 105 DEGREES ON MOST DAYS, WITH SOME AREAS OF EXTREME HEATRISK
GIVEN THE LONGEVITY OF THE HEAT AND EXPECTED HEAT INDICES
EXCEEDING 110 DEGREES AT TIMES. IT WILL ALSO BE QUITE HOT FROM THE
DESERT SOUTHWEST AND EXTENDING NORTH ACROSS THE INTERMOUNTAIN WEST
WITH THE UPPER RIDGE EXERTING ITS INFLUENCE. HIGHS IN THE 110S TO
120F IN THE HOTTEST DESERTS OF SOUTHERN ARIZONA/SOUTHEASTERN
CALIFORNIA WILL ONLY COOL INTO THE UPPER 80S TO MID 90S AT NIGHT.
FARTHER NORTH, TEMPERATURES NEAR 100 DEGREES WILL BE COMMON OVER
THE GREAT BASIN. OVER THE NORTHEAST/MID-ATLANTIC, UPPER TROUGHING
WILL FAVOR NEAR TO BELOW NORMAL TEMPERATURES IN THE GENERALLY
PLEASANT 70S/80S DURING THE DAY AND 50S/60S AT NIGHT.
AN ORGANIZED LOW PRESSURE SYSTEM CROSSING THE NORTHEAST AND MID-
ATLANTIC REGION ON TUESDAY, IN COMBINATION WITH AN AMPLIFYING UPPER
LEVEL SHORTWAVE TROUGH, WILL FUEL THE DEVELOPMENT OF NUMEROUS
SHOWERS AND STORMS FROM VIRGINIA TO NEW ENGLAND. A RISK OF FLASH
FLOODING IS POSSIBLE IN THE REGION TUESDAY INTO WEDNESDAY WITH A
POTENTIAL FOR 1 TO 2+ INCHES OF RAINFALL. THERE IS ALSO A THREAT OF
SEVERE WEATHER ACROSS PORTIONS OF THE MID-ATLANTIC IN THE WARM
SECTOR OF THE LOW PRESSURE SYSTEM. DAMAGING WINDS ARE THE PRIMARY
HAZARD WITH THE STRONGEST STORMS.
ELSEWHERE ACROSS THE COUNTRY, ELEVATED MONSOONAL MOISTURE WILL
LINGER ACROSS THE FOUR CORNERS REGION TO START THE PERIOD OVER THE
CENTRAL AND SOUTHERN ROCKIES. THE BUILDING RIDGING WILL LIKELY
SUPPRESS THE MOISTURE SOURCE SOMEWHAT OVER THE REGION, BUT ISOLATED
TO PERHAPS SCATTERED SHOWERS AND STORMS ARE POSSIBLE INTO THE
START OF NEXT WEEKEND. THE GREATEST COVERAGE IS EXPECTED AROUND THE
CORE OF THE UPPER HIGH -- ACROSS COLORADO AND THEN INTO NORTHERN
NEW MEXICO. FARTHER EAST ACROSS THE PLAINS AND MIDWEST, NORTHWEST
FLOW ALOFT AROUND THE NORTHERN PERIPHERY OF THE UPPER RIDGE SHOULD
SUPPORT THE DEVELOPMENT OF SOME MESOSCALE CONVECTIVE COMPLEXES, BUT
THE TIMING AND PLACEMENT OF THESE REMAIN UNCERTAIN AT THIS TIME.
FRACASSO/HAMRICK
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES
ARE AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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