576
FXUS02 KWBC 221958
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 PM EDT SAT AUG 22 2026
VALID 12Z TUE AUG 25 2026 - 12Z SAT AUG 29 2026
...HAZARDOUS HEAT TO CONTINUE FROM THE LOWER MISSISSIPPI VALLEY
ACROSS THE SOUTHERN PLAINS TO THE DESERT SOUTHWEST...
..OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST SUITE OF GUIDANCE MAINTAINS A WELL CLUSTERED LARGE SCALE
PATTERN OF A STRONG HIGH ANCHORED OVER THE SOUTHWEST ALONG WITH A
MEAN UPPER TROUGH OVER THE EAST-CENTRAL U.S. THROUGH THE EXTENDED
PERIOD. THIS PATTERN WILL HAVE LITTLE CHANGE AS THE WEEK PROGRESSES
AND AS SUCH, WILL SUPPORT A MULTI-DAY HEATWAVE FOR MUCH OF THE
SOUTHERN TIER STATES. HAZARDOUS HEAT WILL BE THE MOST PROMINENT FOR
THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. ALONG THE RIDGE'S
PERIPHERY MONSOONAL MOISTURE WILL PROMOTE SCATTERED CONVECTION
ACROSS THE INTERMOUNTAIN WEST AND ROCKIES AND STRONG CONVECTION
WITH LOCAL DOWNPOURS SPILL ACROSS PARTS OF THE CENTRAL STATES.
SHORTWAVES WILL MAINTAIN UPPER TROUGHING OVER THE EAST-CENTRAL U.S.
TO FAVOR WAVY AND MODERATING FRONTAL SURGES. WRAPPING RAINS
LINGERING OVER THE NORTHEAST EARLY NEXT WEEK AS A LEAD LOW PULLS
AWAY WILL BE FOLLOWED BY BROAD PERIODS WITH ORGANIZED
RAIN/THUNDERSTORMS FOR PORTIONS OF THE EAST/SOUTHEAST THE REST OF
THE WEEK WITH WAVY FRONTAL SYSTEMS.
..WEATHER/HAZARDS HIGHLIGHTS
DAILY MAXIMUM TEMPERATURES
UNDER THE HIGH PRESSURES DAILY TEMPERATURES ACROSS THE SOUTH WILL
CLIMB INTO THE 90S AND 100S WITH OPPRESSIVE HEAT INDICES. RECORD-
BREAKING WARM OVERNIGHT TEMPERATURES ACROSS THE SOUTHERN TIER WILL
FURTHER LIMIT RECOVERY FROM THE HEAT, ESPECIALLY GIVEN HEATWAVE
LONGEVITY WHICH MAY CONTINUE TO HEAT RELATED ILLNESSES. WIDESPREAD
MAJOR TO EXTREME HEATRISK WILL PERSIST IN THE SOUTHERN PLAINS AND
LOWER MISSISSIPPI VALLEY. FOR THE DESERT SOUTHWEST DAY MAXIMUMS MAY
EASILY SOAR TO/ABOVE THE 110S WHICH COULD ALSO CAUSE HEAT CONCERNS
NEXT WEEK. AREAS OF THE SOUTHEAST MAY REACH A FEW DEGREES ABOVE
NORMAL AT TIMES WITH MOIST DEWPOINTS AND HIGH HEAT INDICES. PLEASE
SEE WPC'S KEY MESSAGES FOR MORE DETAILS ON THE EXTREME HEAT.
ELSEWHERE, MOST AREAS WILL SEE NEAR AVERAGE TEMPERATURES, WITH THE
OHIO VALLEY AND VICINITY BELOW AVERAGE.
THE INTERIOR NORTHEAST WILL HAVE CONTINUED CHANCES FOR OVERCAST
SKIES AND WRAPPING RAINS AS THE UPPER LOW MAKES A SLOW EXIT.
MEANWHILE, MONSOONAL MOISTURE WILL BE STREAMING NORTHWARD ALONG THE
PERIPHERY OF THE UPPER RIDGE AND WILL HELP TRIGGER SCATTERED,
DIURNALLY DRIVEN CONVECTION TO THE INTERMOUNTAIN WEST AND ROCKIES.
INDIVIDUAL CELLS MAY LEAD TO ISOLATED INSTANCES OF FLASH FLOODING
FOR SENSITIVE LOCATIONS SUCH AS BURN SCARS, FAVORED TERRAIN LIKE
SLOT CANYONS AND URBAN AREAS. WPC MAINTAINS A MARGINAL RISK FOR
EXCESSIVE RAINFALL FOR BOTH TUESDAY AND WEDNESDAY.
SHORTWAVES ROUNDING THE TOP OF THE RIDGE WILL TRIGGER SHOWERS AND
THUNDERSTORMS ACROSS THE CENTRAL U.S. AND WILL SHIFT SOUTHWEST WITH
TIME. SOME OF THESE STORMS WILL BE STRONG, POSSIBLY SEVERE,
HOWEVER THE EXACT LOCATION AND TIMING REMAINS A BIT UNCERTAIN.
GIVEN THE FRONTAL PROXIMITY AND A POOLING MOISTURE/INSTABILITY
FOCUS OVER THE CENTRAL PLAINS, WPC HAS MARGINAL RISK FOR EXCESSIVE
RAINFALL AREAS IN PLACE. ORGANIZED RAIN/THUNDERSTORM CHANCES FROM
THE MIDWEST/GREAT LAKES EARLY-MID NEXT WEEK WILL WITH WAVY FRONTAL
PUSHES INCREASINGLY SPREAD OVER A HOT/MOIST/UNSTABLE EAST/SOUTHEAST
NEXT WEEK THUS MAINTAINING MARGINAL RISK AREAS FOR
TUESDAY/WEDNESDAY GIVEN REPEAT MULTI-DAY POTENTIAL.
CAMPBELL/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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page