401
FXUS02 KWBC 230742
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 AM EST SUN NOV 23 2025
VALID 12Z WED NOV 26 2025 - 12Z SUN NOV 30 2025
..GENERAL OVERVIEW
A STRONG LOW PRESSURE SYSTEM CROSSING THE NORTHERN GREAT LAKES
MID-WEEK IS EXPECTED TO MOVE OVER QUEBEC, WITH A TRAILING COLD
FRONT THAT SHOULD EXIT THE EAST COAST BY THANKSGIVING MORNING. A
PLEASANTLY MILD AIRMASS AHEAD OF THE BOUNDARY WILL BE REPLACED BY
MUCH COLDER CONDITIONS BY THE END OF THE WEEK, WITH A SPRAWLING
CANADIAN SURFACE HIGH ENVELOPING AREAS FROM THE NORTHERN PLAINS TO
THE SOUTHEAST STATES, AND LAKE EFFECT SNOWS FROM MICHIGAN TO NEW
YORK STATE. AN UPPER LEVEL TROUGH AMPLIFIES ACROSS THE WESTERN U.S.
GOING INTO NEXT WEEKEND, WHICH WILL LIKELY SPUR SURFACE
CYCLOGENESIS ACROSS THE WESTERN HIGH PLAINS BY THIS TIME, AND MORE
OF A ZONAL FLOW PATTERN DEVELOPS OVER THE EASTERN HALF OF THE
NATION.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THERE IS GOOD OVERALL SYNOPTIC SCALE AGREEMENT ACROSS THE
CONTINENTAL U.S. TO BEGIN THE FORECAST PERIOD WEDNESDAY, WITH A
GENERAL MODEL BLEND USED FOR FRONTS AND PRESSURES, AND OVERALL
AGREEMENT HAS IMPROVED WITH FRONTAL TIMING NEAR THE EAST COAST ON
THANKSGIVING WITH THE GFS NOW CLOSE TO THE CONSENSUS. THE QPF FOR
THE GREAT LAKES REGION WAS RAISED SLIGHTLY ABOVE NBM, WHICH IS
PROBABLY UNDERDONE WITH LAKE EFFECT SNOW AMOUNTS WEDNESDAY THROUGH
EARLY FRIDAY.
MODEL DIFFERENCES ARE MORE NOTICEABLE ACROSS THE WESTERN HALF OF
THE NATION GOING INTO NEXT WEEKEND WITH THE EVOLUTION OF THE LARGE
SCALE TROUGH AND THE ASSOCIATION SURFACE LOW DEVELOPMENT OVER THE
WESTERN HIGH PLAINS. AT THE TIME OF FRONTS/PRESSURES PREPARATION, A
SOLUTIONS CLOSER TO THE ECMWF/AIFS/ECENS WAS USED BY SATURDAY AND
SUNDAY, WHICH HAS THE DEVELOPING FRONTAL BOUNDARY FARTHER EAST
ACROSS THE CENTRAL PLAINS, AND THIS ALSO HAD SOME SUPPORT FROM THE
GEFS MEAN. THE GFS AND CMC WERE ON THE WESTERN SIDE OF THE GUIDANCE
WITH RESPECT TO UPPER TROUGH PLACEMENT AND SURFACE LOW DEVELOPMENT.
..WEATHER/HAZARDS HIGHLIGHTS
IN TERMS OF THE EXCESSIVE RAINFALL OUTLOOKS, THE NEW DAY
4/WEDNESDAY ERO MAINTAINS THE MARGINAL RISK AREA ACROSS PORTIONS OF
NORTHWESTERN OREGON AND WESTERN WASHINGTON WHERE AN ATMOSPHERIC
RIVER ADVECTS COPIOUS MOISTURE TOWARDS THE TERRAIN, WITH SOME 2 TO
3 INCH RAINFALL TOTALS LIKELY. THERE WILL PROBABLY BE ABATEMENT IN
THE RAINFALL INTENSITY GOING INTO DAY 5/THANKSGIVING DAY, AND NO
RISK AREAS ARE CURRENTLY WARRANTED NATIONWIDE.
LOOKING AHEAD TO SATURDAY, DEPENDING ON THE LEVEL OF MOISTURE
RETURN AHEAD OF THE DEVELOPING STORM SYSTEM OVER THE PLAINS,
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY FROM THE TEXAS GULF COAST TO THE ARKLATEX REGION. IN
ADDITION, MOISTURE OVER-RUNNING THE ARCTIC AIRMASS OVER THE
NORTHERN PLAINS COULD LEAD TO MORE WIDESPREAD SNOWFALL CHANCES FROM
EASTERN WYOMING TO THE UPPER MIDWEST SATURDAY INTO EARLY SUNDAY,
AND HEAVY SNOW FOR THE HIGHER TERRAIN OF THE CENTRAL ROCKIES.
IN TERMS OF TEMPERATURES, A MILD DAY FOR THIS TIME OF YEAR CAN BE
EXPECTED ON WEDNESDAY FROM FLORIDA TO THE NORTHEAST U.S. WITH HIGHS
RUNNING ABOUT 10-15 DEGREES ABOVE AVERAGE, BUT THIS WILL BE SHORT-
LIVED AS A STRONG COLD FRONT HERALDS THE ARRIVAL OF A DECEMBER-LIKE
AIRMASS TO THE REGION, DROPPING TEMPERATURES ABOUT 20 DEGREES FOR
MANY AREAS BY FRIDAY. A MUCH COLDER ARCTIC AIRMASS THEN OOZES
SOUTHWARD ACROSS MONTANA AND MUCH OF THE DAKOTAS BY NEXT WEEKEND,
WITH SOME SUBZERO OVERNIGHT LOWS WITHIN THE REALM OF POSSIBILITY
NEAR THE CANADIAN BORDER, WHILST TEMPERATURES REMAIN WARM ACROSS
SOUTHERN TEXAS.
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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