115
FXUS02 KWBC 191838
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 PM EDT SAT JUL 19 2025
VALID 12Z TUE JUL 22 2025 - 12Z SAT JUL 26 2025
...MAJOR HEAT WAVE BUILDING FROM THE SOUTHEAST INTO PARTS OF THE
CENTRAL U.S. NEXT WEEK AND BEYOND...
..OVERVIEW
THE OVERALL WEATHER PATTERN NEXT WEEK WILL BE DOMINATED BY A
BUILDING UPPER LEVEL RIDGE THAT WILL BE SITUATED OVER THE SOUTH
AND EXTENDING NORTH TO THE TENNESSEE AND OHIO RIVER VALLEYS. HEAT
AND HUMIDITY BUILD TO DANGEROUS LEVELS ACROSS MUCH OF THE CENTRAL
U.S./MIDWEST AND EXTENDING TO THE SOUTHEAST AND THE SOUTH. AN
ACTIVE FLOW PATTERN WILL BE IN PLACE TO THE NORTH OF THIS HIGH AS
MULTIPLE SHORTWAVE IMPULSES TRACK EASTWARD OVER THE NORTHERN TIER
STATES AND THEN NEW ENGLAND. A COLD FRONT PROVIDES SOME RELIEF FROM
RECENT HEAT AND HUMIDITY FROM THE MID-ATLANTIC TO THE NORTHEAST TO
START THE WEEK, FOLLOWED BY HOTTER WEATHER MID-WEEK AND BEYOND.
MEANWHILE, AN UPPER LEVEL TROUGH LIKELY DEVELOPS NEAR THE WEST
COAST GOING INTO EARLY NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE SOLUTIONS SEEM CLUSTERED MUCH BETTER THAN NORMAL VALID
FOR TUESDAY-THURSDAY IN A PATTERN WITH ABOVE NORMAL PREDICTABILITY
OVERALL. A FAVORED MODEL COMPOSITE HAS GOOD ENSEMBLE SUPPORT AND
PROVIDES A SOLID FORECAST BASIS. FAVOR A SWITCH TO A STILL VERY
REASONABLE COMPOSITE OF THE COMPATIBLE MODELS AND ENSEMBLE MEANS
ALONG WITH WPC CONTINUITY AMID SLOWLY INCREASING FORECAST SPREAD.
..WEATHER/HAZARDS HIGHLIGHTS
AN AXIS OF UNSETTLED WEATHER WILL REMAIN IN PLACE ACROSS THE UPPER
MIDWEST AND ALSO THE SOUTHEAST U.S. FOR THE BEGINNING TO MIDDLE OF
THE WEEK. THUNDERSTORM COMPLEXES TRAVELING AROUND THE NORTHERN
PERIPHERY OF THE BIG UPPER HIGH WILL LIKELY PRODUCE LOCALIZED AREAS
OF HEAVY RAINFALL, POTENTIALLY EXCEEDING AN INCH PER HOUR OR MORE.
THEREFORE, A BROAD MARGINAL RISK AREA EXTENDS FROM THE EASTERN
DAKOTAS TO THE WESTERN GREAT LAKES ON TUESDAY WHERE A COLD FRONT
WILL BE INTERSECTING A WARM AND HUMID AIRMASS TO THE SOUTH. A
SLIGHT RISK HAS BEEN INTRODUCED WITH CONFIDENCE ON THE MAIN QPF
AXIS BECOMING SOME MORE CERTAIN. ACROSS THE SOUTH/SOUTHEAST AND
NORTHERN FLORIDA, A LINGERING STATIONARY FRONT WILL HELP FOCUS DEEP
MOISTURE WITH A POTENTIAL WAVE OF LOW PRESSURE DEVELOPING ALONG
IT, WITH SOME 1-3+ INCH RAINFALL TOTALS POSSIBLE FOR SOME AREAS.
THEREFORE, A MARGINAL RISK AREA IS VALID HERE ON TUESDAY/WEDNESDAY.
HEAT WILL ONCE AGAIN MAKE WEATHER HEADLINES FOR MUCH OF NEXT WEEK
ACROSS A LARGE PORTION OF THE SOUTHERN AND CENTRAL U.S. WITH A
LARGE UPPER HIGH BECOMING ANCHORED OVER THE MID-SOUTH. WIDESPREAD
MAJOR IMPACTS ON THE HEAT RISK SCALE ARE EXPECTED FROM THE CENTRAL
PLAINS TO THE SOUTHEAST STATES EARLY IN THE WEEK, AND THESE HIGHER
IMPACTS THEN REACH THE MIDWEST AND OHIO VALLEY BY MID TO LATE WEEK.
THIS WILL BE DUE TO WIDESPREAD HIGHS IN THE LOWER 90S TO LOW 100S
FOR MANY OF THESE AREAS, IN COMBINATION WITH DEWPOINTS WELL INTO
THE 70S, AND OVERNIGHT LOWS REMAINING UNCOMFORTABLY WARM. THIS WILL
LIKELY HAVE SOME STAYING POWER BEYOND THIS FORECAST PERIOD BASED
ON THE LATEST WEEK TWO OUTLOOK FROM THE CLIMATE PREDICTION CENTER
FROM THE CENTRAL PLAINS TO THE GULF COAST REGION.
ELSEWHERE ACROSS THE NATION, THERE SHOULD BE JUST ENOUGH MONSOONAL
MOISTURE IN PLACE ACROSS EASTERN ARIZONA AND MUCH OF NEW MEXICO,
AND PROBABLY EXTENDING INTO SOUTHERN PORTIONS OF COLORADO, AND
GIVEN THE POTENTIAL FOR SOME ISOLATED SLOW MOVING STORMS, A
MARGINAL RISK IS IN PLACE FOR BOTH TUESDAY AND WEDNESDAY. ACROSS
THE EAST COAST REGION, A COLD FRONT IS FORECAST TO CLEAR THE
NORTHEAST AND THE MID-ATLANTIC REGION THROUGH TUESDAY, AND
BRINGING A HIGHER QUALITY AIRMASS AFTER ALL OF THE HEAT AND
OPPRESSIVE HUMIDITY LATELY AND LOWER RAIN CHANCES. HOWEVER, THE
HEAT WILL LIKELY RETURN TOWARDS THE END OF THE WEEK AS THE CANADIAN
SURFACE HIGH MOVES OFFSHORE AND A MORE SOUTHERLY FLOW COMMENCES.
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 (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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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