317
FXUS02 KWBC 240756
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 AM EST MON NOV 24 2025
VALID 12Z THU NOV 27 2025 - 12Z MON DEC 01 2025
..GENERAL OVERVIEW
A STRONG LOW PRESSURE SYSTEM CROSSING QUEBEC WILL HAVE A TRAILING
COLD FRONT THAT WILL EXIT THE EAST COAST BY THANKSGIVING MORNING.
MUCH COLDER CONDITIONS WILL ARRIVE FOR THE EASTERN U.S. BY THE END
OF THE WEEK, WITH A SPRAWLING CANADIAN SURFACE HIGH ENVELOPING
AREAS FROM THE NORTHERN PLAINS TO THE SOUTHEAST STATES, AND HEAVY
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 THURSDAY, WITH A
GENERAL MODEL BLEND USED FOR FRONTS AND PRESSURES. SIMILAR TO THE
PAST FEW DAYS, THE QPF FOR THE GREAT LAKES REGION WAS RAISED
SLIGHTLY ABOVE NBM, WHICH IS PROBABLY UNDERDONE WITH LAKE EFFECT
SNOW AMOUNTS THURSDAY THROUGH LATE FRIDAY.
MODEL DIFFERENCES ARE MORE NOTICEABLE ACROSS THE WESTERN HALF OF
THE NATION GOING INTO NEXT WEEKEND AND BEYOND WITH THE EVOLUTION
OF THE LARGE SCALE TROUGH AND THE ASSOCIATION SURFACE LOW
DEVELOPMENT OVER THE WESTERN HIGH PLAINS. THE GFS IS STRONGEST IN
DEPICTING A CLOSED LOW THAT HANGS BACK OVER CALIFORNIA BY SUNDAY,
WHEREAS THE CMC AND ECMWF HAVE THE MAIN TROUGH AXIS FARTHER TO THE
EAST OVER THE ROCKIES. THE MODELS ALSO KEEP THE SURFACE LOW ON THE
WEAKER SIDE OF THINGS AND KEEPS IT MORE CONFINED TO THE SOUTHERN
U.S. INSTEAD OF TAKING IT NORTH TOWARDS THE GREAT LAKES. THE
ENSEMBLE MEANS WERE INCREASED TO ABOUT HALF BY NEXT MONDAY.
..WEATHER/HAZARDS HIGHLIGHTS
MOISTURE FROM AN ATMOSPHERIC RIVER ACROSS THE PACIFIC NORTHWEST
MOVES INLAND AND GENERALLY BECOMES LIGHTER GOING INTO THANKSGIVING,
WITH MOST RAINFALL TOTALS UNDER AN INCH FOR THE NEW DAY 4/THURSDAY
TIME PERIOD, SO NO RISK AREAS ARE NECESSARY FOR THE EXCESSIVE
RAINFALL OUTLOOK. THE SAME HOLDS TRUE FOR DAY 5/FRIDAY WITH MAINLY
LIGHT RAIN FOR THE LOWER ELEVATIONS OF THE NORTHWESTERN STATES, AND
SHOWERS BEGIN DEVELOPING FROM TEXAS TO THE MIDWEST, BUT MAINLY
LIGHT TO MODERATE IN INTENSITY, WITH NO RISK AREAS NEEDED. MODERATE
TO HEAVY LAKE EFFECT SNOW WILL ALSO MAKE WEATHER HEADLINES FROM
MICHIGAN TO WESTERN NEW YORK THROUGH LATE FRIDAY, WITH SOME AREAS
POTENTIALLY GETTING 6-12+ INCHES OF SNOW ACCUMULATION.
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 MID-SOUTH, WITH HEAVIER
RAINFALL LIKELY ON SUNDAY. 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 FRIDAY NIGHT INTO SATURDAY, AND HEAVY SNOW FOR THE HIGHER
TERRAIN OF THE CENTRAL ROCKIES.
IN TERMS OF TEMPERATURES, A STRONG COLD FRONT HERALDS THE ARRIVAL
OF A DECEMBER-LIKE AIRMASS TO THE EASTERN U.S. FOR THE END OF THE
WEEK, DROPPING TEMPERATURES ABOUT 20 DEGREES FOR MANY AREAS BY
FRIDAY COMPARED TO THE MILD WEATHER MIDWEEK. 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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