519
FXUS02 KWBC 211956
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 PM EST FRI NOV 21 2025
VALID 12Z MON NOV 24 2025 - 12Z FRI NOV 28 2025
...HEAVY RAIN THREAT FROM THE ARKLATEX TO THE MIDSOUTH ON
MONDAY...
..OVERVIEW
A POTENT SHORTWAVE CROSSING THE SOUTHERN PLAINS MONDAY WILL
SUSTAIN A SURFACE LOW, WITH PLENTY OF DEEP MOISTURE SURGING NORTH
TO SUPPORT WIDESPREAD HEAVY SHOWERS AND THUNDERSTORMS. THIS
SHORTWAVE SHOULD WEAKEN THROUGH TUESDAY AS A STORM SYSTEM OVER THE
NORTHERN PLAINS AND UPPER MIDWEST BECOMES THE DOMINANT WEATHER
FEATURE BY THE MIDDLE OF THE WEEK. THIS WILL USHER IN A MUCH COLDER
CANADIAN SURFACE HIGH BEHIND A COLD FRONT TRACKING TOWARDS THE
EAST COAST AROUND THANKSGIVING. MEANWHILE, PERIODS OF RAIN AND
MOUNTAIN SNOW ARE LIKELY FOR THE PACIFIC NORTHWEST WITH AN ACTIVE
STORM TRACK OVER THE NORTHEAST PACIFIC.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST GUIDANCE CONTINUES TO SHOW OVERALL GOOD SYNOPTIC
AGREEMENT FOR THE BEGINNING OF THE WEEK, BUT THE GFS HAS BEEN
CONSISTENTLY SLOWER TUESDAY AND BEYOND WITH THE PROGRESSION OF THE
MAIN COLD FRONT ACROSS THE EASTERN U.S.. THERE IS BETTER CONSENSUS
FOR A FASTER SOLUTION, SIMILAR TO THE ECMWF, CMC, AI GUIDANCE, AND
THE MEANS AND THAT IS HOW THE WPC FORECAST TODAY TRENDED. OUT WEST,
DISAGREEMENTS BEGIN TO POP UP LATER IN THE WEEK WITH REGARDS TO
WEAKER SHORTWAVES THROUGH THE FLOW AND DEEPER TROUGHING OFF THE
COAST. THE WPC FORECAST USED A NON-GFS BLEND FOR THE FIRST HALF OF
THE PERIOD, TRANSITIONING TO 60 PERCENT OF THE ENSEMBLE MEANS WITH
40 PERCENT OF THE ECMWF AND CMC. THIS APPROACH MAINTAINS GOOD
AGREEMENT WITH THE PREVIOUS WPC FORECAST AS WELL. CHANGES TO THE
NBM WITH RESPECT TO THE GRIDDED FORECAST WERE BASED OFF THE ABOVE
PREFERENCES TOO, WITH MOST CHANGES SURROUNDING DECREASING PRECIP
ACROSS THE EAST MID WEEK AND INCREASING PRECIPITATION ACROSS THE
GREAT LAKES ON THE BACKSIDE OF THE SYSTEM.
..WEATHER/HAZARDS HIGHLIGHTS
WIDESPREAD MODERATE TO HEAVY RAINFALL AND REPEATING ROUNDS OF
THUNDERSTORMS, IS LIKELY FROM NORTHEASTERN TEXAS TO THE GREATER
MEMPHIS METRO AREA. THIS REGION WILL BE IN THE WARM AND HUMID
SECTOR OF A DEVELOPING STORM SYSTEM. IN TERMS OF THE EXCESSIVE
RAINFALL OUTLOOKS, THE DAY 4/MONDAY PERIOD FEATURES A SLIGHT RISK
AREA FROM NORTHEAST TEXAS INTO MUCH OF ARKANSAS AND FAR
NORTHWESTERN MISSISSIPPI. FOR DAY 5/TUESDAY OUTLOOK, A MARGINAL
RISK IS IN PLACE FROM MISSISSIPPI TO THE SOUTHERN APPALACHIANS
WHERE THE BEST MODEL SIGNAL EXISTS FOR ORGANIZED SHOWERS AND
STORMS, ALBEIT SOME WEAKENING IS EXPECTED COMPARED TO SUNDAY AND
MONDAY. SHOWERS WILL ALSO ACCOMPANY THE COLD FRONT AS IT ADVANCES
THROUGH THE EAST TUESDAY INTO WEDNESDAY, WITH MOST GUIDANCE, AT
THIS POINT, SUGGESTING IT CLEARS THE COAST JUST IN TIME FOR
THANKSGIVING. COLD AIR ADVECTION COMBINED WITH THE DEFORMATION ZONE
ON THE WESTERN SIDE OF THE UPPER MIDWEST STORM SYSTEM WILL LIKELY
RESULT IN MODERATE SNOW FROM THE DAKOTAS TO NORTHERN MINNESOTA. OUT
WEST, A POTENTIAL ATMOSPHERIC RIVER INTO THE REGION LOOK TO ADVECT
AMPLE MOISTURE RESULTING IN MODERATE TO HEAVY MID- WEEK RAIN AND
HIGHER ELEVATION SNOWS.
TEMPERATURES ARE EXPECTED TO BE MILD FOR THIS TIME OF YEAR FROM
THE GULF COAST TO THE GREAT LAKES REGION AHEAD OF THE COLD FRONT,
WITH HIGHS RUNNING 5-15+ DEGREES ABOVE LATE NOVEMBER AVERAGES
THROUGH TUESDAY. THIS MILD AIRMASS THEN REACHES THE EAST COAST BY
WEDNESDAY WITH HIGHS WELL INTO THE 50S AND 60S FOR MANY AREAS,
FOLLOWED BY A RETURN TO SLIGHTLY BELOW AVERAGE CONDITIONS TO CLOSE
OUT THE WEEK. THERE WILL BE ENOUGH COLD AIR ADVECTION ACROSS THE
GREAT LAKES TO SUPPORT LAKE EFFECT SNOWS ACROSS NORTHERN MICHIGAN,
AND ALSO FROM NORTHEAST OHIO TO CENTRAL NEW YORK FOR THANKSGIVING
AND INTO EARLY FRIDAY. A MODEST WARM-UP IS LIKELY FOR THE
NORTHWESTERN U.S. TOWARDS THANKSGIVING AS THE EARLY COLDER AIRMASS
MODIFIES AND FLOW FROM THE PACIFIC MOVES INTO THE REGION.
SANTORELLI/HAMRICK
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 (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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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