179
FXUS02 KWNH 020650
PREEPD
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 AM EDT THU JUL 2 2026
VALID 12Z SUN JUL 05 2026 - 12Z THU JUL 09 2026
...SIGNIFICANT AND DANGEROUS OHIO VALLEY TO EAST HEAT WAVE TO WANE
FOR MOST BY THE END OF THIS WEEKEND...
..PATTERN OVERVIEW
THE STRONG RIDGE SUPPORTING A SIGNIFICANT AND DANGEROUS HEAT WAVE
DURING THE SHORT RANGE PERIOD SHOULD BE WEAKENING BY THE START OF
THE MEDIUM RANGE PERIOD, HOWEVER HAZARDOUS HEAT MAY STILL CONTINUE
THROUGH SUNDAY FOR PARTS OF THE OHIO VALLEY INTO THE EAST,
LINGERING A BIT LONGER INTO EARLY NEXT WEEK FOR THE SOUTHEAST.
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
EASTERN HALF OF THE COUNTRY INTO NEXT WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST GUIDANCE CONTINUES TO BE REASONABLY WELL CLUSTERED
THROUGH MUCH OF THE PERIOD, ESPECIALLY ON THE LARGE SCALE. A
GENERAL DETERMINISTIC MODEL BLEND SEEMED TO HANDLE THE EARLY PERIOD
FORECAST, FEATURING A SHORTWAVE SKIRTING THE U.S./CANADA BORDER
AND GENERAL TROUGHING OVER THE NORTHEAST. BY TUESDAY NEXT WEEK,
ANOTHER SHORTWAVE WILL ENTER THE NORTHWEST AND THERE IS QUITE A BIT
OF UNCERTAINTY REGARDING THE TIMING AND AMPLITUDE OF THIS FEATURE,
WHICH DIRECTLY IMPACTS THE STRENGTH OF THE RIDGE TO THE SOUTH OVER
THE FOUR CORNERS. SEEMS A BLEND TOWARDS MAJORITY ENSEMBLE MEAN
GUIDANCE WORKED BEST TO MITIGATE THESE UNCERTAINTIES.
..WEATHER/HAZARDS HIGHLIGHTS
A MAJOR ONGOING HEAT WAVE OVER MUCH OF THE MIDWEST INTO THE EAST
SHOULD FINALLY BE LESSENING BY THE START OF THE PERIOD. THOUGH NOT
AS HOT AS THE SHORT RANGE, TEMPERATURES MAY STILL REMAIN WELL ABOVE
NORMAL INTO SUNDAY FOR PARTS OF THE OHIO VALLEY INTO THE EAST.
MAXIMUM TEMPERATURES INTO SUNDAY MAY STILL APPROACH THE 90S TO LOW
100S FOR SOME, BUT ARE MORE UNCERTAIN AND POSSIBLY COULD BE
RESTRICTED BY INCREASING CLOUDS/CONVECTION AS THE RIDGE BREAKDOWN
CONTINUES. HEATRISK CONTINUES TO REMAIN IN THE MAJOR TO EXTREME
CATEGORY INTO SUNDAY THOUGH, WITH MAJOR TO LOCALIZED EXTREME EVEN
PERSISTING LONGER ACROSS THE SOUTHEAST.
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 INTO THE MID-ATLANTIC AND NORTHEAST.
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 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
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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