195
FXUS02 KWBC 271958
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 PM EDT MON JUL 27 2026
VALID 12Z THU JUL 30 2026 - 12Z MON AUG 03 2026
...LONG DURATION HEAT WAVE TO SPREAD FROM THE SOUTHERN
ROCKIES/PLAINS TO THE SOUTHWEST/WEST/ROCKIES/HIGH PLAINS....
..PATTERN OVERVIEW
A HOT UPPER RIDGE WILL BUILD FROM THE SOUTHERN PLAINS/ROCKIES
THROUGH THE SOUTHWEST/WEST AND THEN NORTHEASTWARD UP THROUGH THE
ROCKIES/HIGH PLAINS OVER THE NEXT WEEK TO SUPPORT A LENGTHY AND
ANOMALOUSLY POTENT HEAT WAVE. THIS RIDGE WILL MEANWHILE BE
SANDWICHED BY AN UPSTREAM UPPER TROUGH/CLOSED LOW FROM THE
NORTHEAST PACIFIC TO THE PACIFIC NORTHWEST AND A FAR DOWNSTREAM
AMPLIFIED TROUGH OVER THE NORTHEAST. THIS POTENT CLOSED LEAD
TROUGH/LOW WILL BE SLOW TO DEPART THE NORTHEAST STATES ALONG WITH
HEAVIEST RAINFALL LATE WEEK IN COOLED/UNSETTLED FLOW. MULTIPLE
ADDITIONAL INFLUXES OF DIGGING NORTHERN STREAM ENERGY WILL MAINTAIN
AN OVERALL TROUGH POSITION OVER THE EAST-CENTRAL U.S. WELL INTO
NEXT WEEK ALONG WITH ADDITIONAL PROSPECTS FOR SHOWERS AND STORMS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
RECENT MODEL GUIDANCE FEATURES GOOD OVERALL SYNOPTIC SCALE
AGREEMENT ACROSS THE CONTINENTAL U.S. TO CLOSE OUT THE WORKWEEK,
WITH THE BEST AGREEMENT NOTED ON THE CLOSED UPPER HIGH CENTER
POSITIONED ACROSS THE INTERIOR WESTERN U.S. THROUGH THE WEEKEND
INTO NEXT WEEK. GUIDANCE HAS STARTED COMING INTO BETTER FOCUS WITH
A SHORTWAVE TROUGH TRACKING FROM THE UPPER MIDWEST TO THE TENNESSEE
VALLEY INTO SUNDAY, WITH THE GFS SLIGHTLY MORE PROGRESSIVE IN
BRINGING THE TROUGH SOUTHWARD. RECENT UKMET RUNS DIFFER THE MOST
WITH A STRONGER SURFACE LOW BY SATURDAY MORNING AND ONWARD
DOWNSTREAM. THERE IS ALSO IMPROVED AGREEMENT WITH THE NORTHEAST
PACIFIC CLOSED LOW/TROUGH THAT MOVES INLAND ACROSS SOUTHERN CANADA
INTO MONDAY. OTHERWISE, A COMPOSITE GUIDANCE BLEND SEEMS TO PROVIDE
A GOOD FORECAST BASIS WITH OVERALL ABOVE NORMAL PREDICTABILITY.
..WEATHER/HAZARDS HIGHLIGHTS
IT GENERALLY REMAINS THE CASE THAT THE COASTAL LOW THAT WILL BE
AFFECTING THE NORTHEAST U.S. FOR THE MIDDLE OF THIS WEEK WILL
SLOWLY EXIT THE REGION AND TAKE MOST OF THE HEAVY RAINFALL OUT TO
SEA BY FRIDAY. LINGERING SHOWERS AND BREEZY CONDITIONS WILL REMAIN
ACROSS NEW ENGLAND IN THIS PERIOD. THE AREA WITH THE HEAVIEST
RAINFALL TO CLOSE OUT THE WORK WEEK WILL LIKELY BE ACROSS THE
MIDWEST AS A SHORTWAVE DISTURBANCE ALOFT PROMOTES THE DEVELOPMENT
OF MESOSCALE CONVECTIVE COMPLEXES THAT WILL LIKELY BRING MULTIPLE
ROUNDS OF HEAVY RAINFALL AND STRONG THUNDERSTORMS, WITH A SLIGHT
RISK OF EXCESSIVE RAINFALL EXTENDING FROM EASTERN SOUTH DAKOTA TO
ILLINOIS AND VICINITY OVER THE THURSDAY TO FRIDAY TIME PERIOD.
ADDITIONAL HEAVY RAINFALL IS LIKELY ACROSS PORTIONS OF THE DEEP
SOUTH AND GULF COAST REGION LATER WEEK AND ESPECIALLY GOING INTO
NEXT WEEKEND AS A FRONTAL BOUNDARY STALLS OUT ACROSS THE REGION,
AND SHOWERS/STORMS BECOME MORE WIDESPREAD FOR THE EASTERN U.S. BY
SUNDAY AND INTO MONDAY. DAILY AFTERNOON AND EVENING THUNDERSTORMS
ARE EXPECTED FROM THE CENTRAL ROCKIES TO THE DESERT SOUTHWEST
THROUGH SATURDAY, WITH SLIGHTLY LESS MONSOONAL MOISTURE EXPECTED
INTO SUNDAY AND MONDAY AS THE UPPER HIGH EXPANDS OVER THE REGION.
WIDESPREAD HEAT WILL CONTINUE TO MAKE WEATHER HEADLINES ACROSS A
LARGE PORTION OF THE WESTERN AND CENTRAL U.S. AS A LARGE UPPER
RIDGE BECOMES PARKED OVER THE SOUTHWESTERN QUADRANT OF THE COUNTRY.
THE MOST EXTREME HEAT IS EXPECTED OVER THE LOWER ELEVATIONS OF THE
DESERT SOUTHWEST THROUGH MUCH OF THE FORECAST PERIOD, WITH HIGHS
WELL INTO THE 110S AND APPROACHING 120 DEGREES IN SOME INSTANCES,
AND READINGS NEAR 100 DEGREES EXTENDING NORTH INTO SOUTHERN IDAHO
AND WESTWARD TO INCLUDE THE CENTRAL VALLEY OF CALIFORNIA. ANOTHER
AREA OF EXCESSIVE HEAT IS LIKELY FROM MONTANA INTO WESTERN PORTIONS
OF THE DAKOTAS WITH HIGHS REACHING OR SURPASSING 100 DEGREES NEXT
WEEKEND BEFORE A COLD FRONT PASSES THROUGH EARLY NEXT WEEK. HOT AND
HUMID CONDITIONS WILL CONTINUE THROUGH THE END OF THE WEEK ACROSS
THE GULF COAST REGION, WITH HEAT INDICES ON THE ORDER OF 105-115
DEGREES WITH DEWPOINTS WELL INTO THE 70S SOUTH OF THE STALLED
FRONT. A SLIGHT ABATEMENT IN THE HEAT IS LIKELY BY THE WEEKEND WITH
MORE CLOUDS AND RAINFALL ACROSS THE REGION.
HAMRICK/SCHICHTEL
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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