374
FXUS02 KWBC 011836
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EDT WED JUL 1 2026
VALID 12Z SAT JUL 04 2026 - 12Z WED JUL 08 2026
...SIGNIFICANT HEAT WAVE EXPECTED TO LAST INTO AT LEAST SATURDAY
FOR THE MIDWEST TO EASTERN U.S. BEFORE WANING EARLY NEXT WEEK..
..PATTERN OVERVIEW
IT REMAINS THE CASE THAT THE STRONG RIDGE SUPPORTING A SIGNIFICANT
AND DANGEROUS HEAT WAVE DURING THE SHORT RANGE PERIOD SHOULD
FINALLY BEGIN TO WEAKEN SOMEWHAT BY THE MEDIUM RANGE PERIOD,
HOWEVER HAZARDOUS HEAT MAY STILL CONTINUE THROUGH THE WEEKEND,
ESPECIALLY FOR PARTS OF THE EAST. ENERGY FROM THE WEST SHOULD
EVENTUALLY WORK ITS WAY INTO THE NORTHERN PLAINS AND GREAT LAKES
SUPPRESSING THE RIDGE COMPLETELY BY EARLY NEXT WEEK. RIDGING THEN
LOOKS TO BUILD BACK INTO THE FOUR CORNERS REGION NEXT WEEK. SHOWERS
AND STORMS WILL EXPAND ACROSS THE OHIO VALLEY AND THE SOUTH/EAST
NEXT WEEKEND AND INTO NEXT WEEK AS THE RIDGE WEAKENS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
GUIDANCE SOLUTIONS CONTINUE TO BE REASONABLY WELL CLUSTERED AT
MID-LARGER SCALES AS IS OFTEN THE CASE DURING THE WARM SEASON IN
THE ABSENCE OF ORGANIZED TROPICAL SYSTEMS. MOST LINGERING MODEL,
ENSEMBLE AND MACHINE LEARNING GUIDANCE ISSUES REMAIN AT SMALLER
SCALES AND ESPECIALLY WITH CONVECTIVE FOCUS. A COMPOSITE GUIDANCE
BLEND FAVORING THE MODELS OVER THE WEEKEND AND THE ENSEMBLE MEANS
AND MACHINE LEARNING GUIDANCE NEXT WEEK SEEMS TO BEST MITIGATE
SMALLER SCALE VARIANCES AS CONSISTENT WITH INDIVIDUAL FEATURE
PREDICTABILLITY THAT LOWERS OVER TIME.
..WEATHER/HAZARDS HIGHLIGHTS
THE FOCUS FOR A MAJOR ONGOING HEAT WAVE WILL PERSIST THROUGH THE
HOLIDAY WEEKEND FROM PARTS OF THE MIDWEST INTO MUCH OF THE EAST.
WIDESPREAD AND DAILY RECORD BREAKING MAXIMUM TEMPERATURES INTO THE
90S TO LOW 100S, COMBINED WITH HIGH HUMIDITY, WILL RESULT IN HEAT
INDICES APPROACHING OR EXCEEDING 105-110 IN MANY PLACES, ESPECIALLY
FOR SATURDAY. THIS EQUATES TO SOME WIDESPREAD MAJOR TO EXTREME
HEATRISK THREATS. OVERNIGHT LOWS WILL LINGER AND ALSO BE QUITE
WARM, WITH NUMEROUS RECORD HIGH MINIMUMS POSSIBLE, BRINGING LITTLE
TO NO RELIEF FROM THE HEAT IN THE NIGHTTIME HOURS. HEAT MAY FINALLY
BEGIN TO ABATE BY SUNDAY, WITH UPPER TEMPERATURE LIMITS THROUGH
THE WEEKEND POSSIBLY RESTRICTED BY INCREASING CLOUDS/CONVECTION AS
RIDGE BREAKDOWN BEGINS. ABOVE NORMAL TEMPERATURES SHOULD EXPAND
WESTWARD INTO THE SOUTHERN AND CENTRAL PLAINS AS WELL, WITH
TEMPERATURES OUT WEST NEAR TO BELOW NORMAL UNDERNEATH OF
GENERAL/WEAKENED TROUGHING.
RAIN AND THUNDERSTORMS SHOULD EXPAND IN COVERAGE ACROSS MUCH OF
THE EASTERN HALF OF THE NATION THIS WEEKEND WITHIN A VERY WARM,
MOIST, AND UNSTABLE AIR MASS. FAIRLY WEAK OVERALL FLOW MAY ALSO
HELP TO SUPPORT AT LEAST A LOCALIZED FLASH FLOOD THREAT ACROSS MUCH
OF THIS REGION, WITH POSSIBLY SOME BETTER CONVECTION FOCUS NEAR A
WAVY FRONTAL BOUNDARY FROM THE MIDWEST TO THE MID-ATLANTIC. WPC
MARGINAL RISKS ARE IN PLACE FROM THE NORTH-CENTRAL PLAINS INTO
PARTS OF THE EAST FOR THE DAYS 4/SATURDAY AND 5/SUNDAY EXCESSIVE
RAINFALL OUTLOOKS.
ELSEWHERE, DIURNALLY DRIVEN SHOWERS AND STORMS ARE EXPECTED FROM
PARTS OF THE CENTRAL GULF COAST TO FLORIDA MOST OF THE PERIOD WITH
INCREASING MOISTURE. SHOWERS MAY REFIRE AGAIN LATER IN THE PERIOD
FOR PARTS OF THE SOUTHERN/CENTRAL ROCKIES AND HIGH PLAINS, AS WELL
AS THE NORTHERN TIER AHEAD OF ADDITIONAL SHORTWAVE ENERGY. THE REST
OF THE WEST LOOKS TO REMAIN MOSTLY DRY OVER THIS FORECAST PERIOD.
SANTORELLI/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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