895
FXUS02 KWBC 241901
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 PM EDT FRI JUL 24 2026
VALID 12Z MON JUL 27 2026 - 12Z FRI JUL 31 2026
...WESTERN, CENTRAL AND SOUTHERN U.S. HAZARDOUS HEAT CONTINUES
INTO NEXT WEEK WHILE MONSOONAL RAINS PROCEED OVER THE FOUR CORNERS
STATES...
...HEAVY RAIN/CONVECTIVE POTENTIAL FROM THE OHIO VALLEY TO
NORTHEAST/MID-ATLANTIC EARLY NEXT WEEK...
..PATTERN OVERVIEW
A PERSISTENT UPPER-LEVEL RIDGE CENTERED OVER CENTRAL U.S. WILL
MAINTAIN DANGEROUS HEAT ACROSS MUCH OF THE CENTRAL-SOUTHERN U.S.
AND THE SOUTHEAST. MEANWHILE, TROUGHING OVER EASTERN U.S. WILL
SUPPORT A MORE ACTIVE PATTERN FROM THE GREAT LAKES AND OHIO VALLEY
TO THE MID-ATLANTIC AND EAST COAST, WITH REPEATED ROUNDS OF SHOWERS
AND THUNDERSTORMS. MONSOONAL MOISTURE WILL CONTINUE TO STREAM
NORTHWARD INTO THE FOUR CORNERS REGION, PROMOTING SCATTERED TO
NUMEROUS THUNDERSTORMS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS ARE IN REASONABLY GOOD AGREEMENT ON THE OVERALL SYNOPTIC
PATTERN EVOLUTION DURING THE MEDIUM RANGE. THE MAIN AREA OF
UNCERTAINTY SURROUNDS THE TIMING/SPEED OF NORTHERN STREAM ENERGY
PROPAGATING THROUGH SOUTHERN CANADA NEXT WEEK. THE GFS, UKMET AND
CANADIAN SLOW DOWN AND DIG THE SHORTWAVE INTO THE NORTHEAST/LOWER
GREAT LAKES MID-WEEK, WHILE THE EURO SUITE (INCLUDING THE ECAIFS).
THUS A GENERAL MODEL BLEND CONSISTING OF A COMPOSITE BLEND OF THE
AVAILABLE DETERMINISTIC AND AI GUIDANCE WERE USED IN THE DAYS 3-5
BLEND. THIS WAS FOLLOWED BY A MAJORITY ENSEMBLE MEAN BLEND ON DAYS
6-7 TO MITIGATE SOME OF THE DISCREPANCY BETWEEN DETERMINISTIC
MODELS REGARDING THE MID-LEVEL DISTURBANCE EVOLUTION IN THE GREAT
LAKES/NORTHEAST MID-TO-LATE-WEEK.
..WEATHER/HAZARDS HIGHLIGHTS
THE DOMINATE SENSIBLE WEATHER STORY REMAINS THE PERSISTENCE OF
ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF SOUTHERN AND CENTRAL U.S.
BENEATH THE UPPER-LEVEL RIDGE. AFTERNOON HIGHS ARE FORECAST TO
REACH THE UPPER 90S AND LOWER 100S ACROSS THE PLAINS, MISSISSIPPI
VALLEY, AND THE SOUTHEAST, WITH OVERNIGHT LOW REMAINING WELL ABOVE
CLIMATOLOGICAL NORMALS. COMBINED WITH HIGH HUMIDITY VALUES,
WIDESPREAD HEAT INDICES EXCEEDING 105 DEGREES APPEAR LIKELY, WITH
LOCALIZED VALUES APPROACHING 115, WHERE CLOUD COVER REMAINS
LIMITED. THIS WILL LEAD TO MAJOR TO EXTREME HEATRISK THREATS ACROSS
CENTRAL U.S. AND THE SOUTHEAST EARLY NEXT WEEK, AND GRADUALLY
ISOLATING TO SOUTH-CENTRAL U.S. AND THE SOUTHEAST THROUGH THE
REMAINDER OF THE WEEK.
OVER THE NORTHERN PERIPHERY OF THE RIDGE, MULTIPLE SHORTWAVE
DISTURBANCES WILL INTERACT WITH A FRONTAL BOUNDARY EXTENDING FROM
THE INTERMOUNTAIN WEST ACROSS THE DAKOTAS INTO THE GREAT LAKES,
SERVING AS A PRIMARY CORRIDOR FOR ORGANIZED CONVECTION. STRONG
INSTABILITY, ABUNDANT MOISTURE, AND DEEP-LAYER SHEAR MAY PROMOTE
REPEATED ROUNDS OF CONVECTION, WHICH MAY LEAD TO HEAVY RAINFALL
ACROSS THE GREAT LAKES/OHIO VALLEY ON MONDAY. THE FRONTAL BOUNDARY
GRADUALLY SHIFTS EASTWARD BY TUESDAY, BRINGING CHANCES FOR HEAVY
RAINFALL AND THUNDERSTORMS ACROSS PORTIONS OF THE MID-
ATLANTIC/OHIO VALLEY INTO THE NORTHEAST. THEREFORE, A MARGINAL
RISK OF EXCESSIVE RAINFALL HAVE BEEN PLACED FOR MONDAY ACROSS THE
GREAT LAKES/OHIO VALLEY, WITH THE RISK SHIFTING ACROSS MUCH OF THE
NORTHEAST ON TUESDAY.
ACROSS THE SOUTHWEST, AN ACTIVE MONSOON PATTERN PERSIST THROUGH
MUCH OF THE WEEK. DEEP TROPICAL MOISTURE CIRCULATING AROUND THE
WESTERN FLANK OF THE SUBTROPICAL RIDGE WILL CONTINUE TO SUPPORT
CONVECTION ACROSS THE FOUR CORNERS EARLY NEXT WEEK, AND GRADUALLY
EXPANDING INTO THE ROCKIES AND PLAINS BY MID-WEEK. THE POTENTIAL
FOR HEAVY RAINFALL RATES WILL LEAD TO LOCALIZED FLASH FLOODING
CONCERNS, ESPECIALLY OVER RECENT BURN SCARS, STEEP TERRAIN, AND
OTHER SENSITIVE AREAS SUSCEPTIBLE TO FLOODING. THEREFORE, A
MARGINAL RISK ARE IN PLACE FOR MONDAY AND TUESDAY FOR WPC EXCESSIVE
RAINFALL OUTLOOK (ERO).
TOWARDS MID-WEEK, THE FRONTAL BOUNDARY WILL DRAPE ACROSS THE
SOUTHEAST, BRINGING SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF
THE SOUTHEAST. WITH THE COMBINATION OF TROPICAL MOISTURE AND SLOW
MOVING STORMS, CHANCES FOR ISOLATED FLASH FLOODING REMAINS
POSSIBLE.
KEBEDE/OUDIT
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