852
FXUS02 KWBC 111939
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
339 PM EDT FRI SEP 11 2026
VALID 12Z MON SEP 14 2026 - 12Z FRI SEP 18 2026
...HAZARDOUS HEAT OVER THE SOUTHERN PLAINS AS HEAVY RAIN AND SEVERE
WEATHER THREATS EMERGE ACROSS THE MIDWEST/GREAT LAKES EARLY NEXT
WEEK...
..OVERVIEW
UPPER-LEVEL RIDGING IS EXPECTED TO BUILD ACROSS THE SOUTHEAST AND
SOUTH-CENTRAL U.S. NEXT WEEK. THIS RIDGE WILL BE RESPONSIBLE FOR
CONTINUED HAZARDOUS HEAT FROM THE SOUTHERN PLAINS TO MID-SOUTH.
MEANWHILE, ROUNDS OF SHORTWAVE ENERGY PROPAGATING THROUGH THE
NORTHERN TIER AND GENERAL TROUGHING OVER THE NORTHEAST AND
NORTHWEST WILL FUEL SEVERE WEATHER AND EXCESSIVE RAINFALL CONCERNS
PRIMARILY ACROSS PORTIONS OF THE MIDWEST/GREAT LAKES EARLY TO
MIDDLE OF NEXT WEEK. CONTINUED MONSOONAL MOISTURE IN THE SOUTHWEST
WILL ALSO ALLOW FOR CONTINUED ISOLATED TO SCATTERED FLASH FLOODING
CONCERNS.
..GUIDANCE/PREDICTABILITY ASSESSMENT
OVERNIGHT AND EARLY MORNING MODELS WERE IN FAIRLY GOOD AGREEMENT
WITH THE OVERALL PATTERN UNTIL THE 06Z GFS, AND GEFS TO A LESSER
DEGREE, DIVERGED BY DAY 5 WITH A FASTER AND PHASED SOLUTION
ASSOCIATED WITH A STRONG SHORTWAVE THAT IS EXPECTED TO ENTER THE
NORTHWEST ON TUESDAY. AI GUIDANCE AND THE ECMWF/CMC SPLIT THE FLOW
AND LEFT THE SHORTWAVE TO CUT OFF INTO AN UPPER LOW NEAR THE WEST
COAST BEFORE SHEERING INTO A WEAK POSITIVELY TILTED TROUGH BY THE
END OF NEXT WEEK. IT IS WORTH NOTING THAT THE 12Z GFS DID TREND
AWAY FROM IT'S FAST AND PHASED SOLUTION AND TOWARDS THE GENERAL
(SLOWER) CONSENSUS WITH THIS FEATURE.
A GENERAL MODEL BLEND CONSISTING OF THE AVAILABLE DETERMINISTIC
AND AI GUIDANCE IS USED ON DAYS 3-4. THE 06Z GFS WAS REMOVED FROM
THE BLEND FOR DAYS 5-7 AND REPLACED WITH A MORE ENSEMBLE MEAN AND
AI FAVORED BLEND DUE TO LINGERING UNCERTAINTIES WITH THE NORTHERN
STREAM SHORTWAVES AND WEST COAST TROUGH.
..WEATHER/HAZARDS HIGHLIGHTS
A POTENT LOW PRESSURE SYSTEM MOVING FROM THE NORTHERN PLAINS TO
SOUTH-CENTRAL CANADA WILL STALL ONE OF ITS ATTENDANT FRONTS
STRETCHING FROM THE CENTRAL PLAINS TO THE LOWER GREAT LAKES THROUGH
AT LEAST THURSDAY. THIS WILL LEAD TO A MULTI- DAY HEAVY RAIN
THREAT WITH THE POTENTIAL FOR EXCESSIVE RAINFALL LEADING TO FLASH
FLOODING TO DEVELOP. THIS THREAT IS EXPECTED TO BEGIN OVER THE
UPPER MIDWEST/GREAT LAKES ON MONDAY ALONG WITH SOME SEVERE WEATHER
POTENTIAL EXTENDING FROM THE CENTRAL PLAINS TO THE MIDDLE
MISSISSIPPI VALLEY. THE EXCESSIVE RAINFALL THREAT REDEVELOPS OVER
THE CENTRAL PLAINS INTO THE MIDDLE/UPPER MISSISSIPPI VALLEY ON
TUESDAY AND CONTINUES THROUGH WEDNESDAY. A SLIGHT RISK (LEVEL 2/4)
OF EXCESSIVE RAINFALL IS IN EFFECT FOR MONDAY AND TUESDAY FROM
EASTERN KANSAS TO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS.
A STRONG RIDGE (POTENTIALLY A RECORD MAX FOR MID-SEPTEMBER PER THE
NAEFS ESAT) OVER THE SOUTH AND SOUTHEAST WILL GENERATE WELL ABOVE
AVERAGE TEMPERATURES ACROSS THE CENTRAL/SOUTHERN PLAINS AND INTO
THE LOWER MISSISSIPPI VALLEY/MID-SOUTH NEXT WEEK. HEAT INDICES
BETWEEN 100-110 DEGREES MAY SUPPORT MAJOR TO LOCALLY EXTREME
HEATRISK OVER PORTIONS OF THE AFOREMENTIONED AREAS BETWEEN MONDAY
AND WEDNESDAY.
THE RETURN OF THE CENTRAL U.S. RIDGE SHOULD REINVIGORATE MONSOONAL
STORMS ACROSS THE SOUTHWEST BEGINNING EARLY NEXT WEEK. MOIST
SOUTHERLY FLOW INTO THE SOUTHWEST COULD PRODUCE ISOLATED INSTANCES
OF FLASH FLOODING ACROSS PORTIONS OF EASTERN ARIZONA THROUGH MUCH
OF NEW MEXICO. BURN SCARS, DRY WASHES AND SLOT CANYONS ARE
ESPECIALLY SENSITIVE TO ANY HEAVY RAINFALL THAT OCCURS.
ADDITIONALLY, PERSISTENT EASTERLY FLOW ACROSS THE FLORIDA
PENINSULA ALONG WITH AN EMBEDDED WEAK UPPER LOW/TROUGH WILL
INCREASE RAINFALL CHANCES ACROSS THE SOUTHERN HALF OF THE STATE AS
WELL AS SPECIFICALLY THE URBAN CORRIDOR OF SOUTHEAST FLORIDA.
SNELL/KEBEDE
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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