077
FXUS02 KWBC 240801
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 AM EST WED DEC 24 2025
VALID 12Z SAT DEC 27 2025 - 12Z WED DEC 31 2025
..OVERVIEW
AMPLIFIED UPPER RIDGING WILL SHIFT THROUGH THE EAST-CENTRAL U.S.
INTO THE WEEKEND, AS SPLIT UPPER TROUGHING SHIFTS INLAND OVER THE
WEST TO BRING AN END TO A VERY WET PERIOD. IMPACTING CALIFORNIA.
WIDESPREAD, BUT RELATIVELY MODEST ACTIVITY WILL ALSO CONTINUE IN
THIS PERIOD FOR THE INTERMOUNTAIN WEST AND ROCKIES. ACROSS THE
CENTRAL TO EAST-CENTRAL U.S., EXPECT UNSEASONABLE WARMTH WITH
RECORD TEMPERATURES INTO THE WEEKEND BEFORE STARK FRONTAL PASSAGE.
THE COLDER NORTHERN TIER WILL HAVE SEVERAL PLOWABLE SNOW CHANCES
FROM THE GREAT LAKES TO THE NORTHERN MID-ATLANTIC/NORTHEAST WITH
ADVENT OF NORTHERN STREAM UPPER TROUGHING AND WAVY FRONTAL SYSTEMS.
EXPECT ENHANCED LAKE EFFECT SNOWS SUNDAY/MONDAY IN STRONG COLD
FLOW IN THE WAKE OF MAIN LOW PASSAGE.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODELS AND ENSEMBLE FORECAST SPREAD STILL SEEMS MANAGEABLE THROUGH
MEDIUM RANGE TIME SCALES IN A SPLIT FLOW PATTERN OVER THE LOWER 48
HIGHLIGHTED BY AN ENERGETIC AND STEADILY PROGRESIVE NORTHERN
STREAM AND SEPARATED/SLOWER SOUTHERN STREAM. WHILE PREDICTABILITY
HAS IMPROVED WITH THE EVOLUTION OF THIS PATTERN OVER MUCH OF THE
NEXT WEEK, REMAINING DIFFERENCES CAN BE PARTIALLY MITIGATED AS
CONSISTENT WITH UNCERTAINTY WITH USAGE OF A COMPOSITE BLEND OF BEST
CLUSTERED GUIDANCE OF THE GFS/ECMWF AND GEFS/ECMWF ENSEMBLE MEANS,
ALBEIT WITH GREATER LINGERING UNCERTAINTIES STILL ASSOCIATED
WITH THE HANDLING OF SOUTHERN STREAM UPPER TROUGHING OVER/OFF THE
SOUTHWEST U.S. INTO NEXT WEEK. EVEN SO, THE WPC SOLUTION MAINTAINS
GOOD PRODUCT CONTINUITY IN LINE WITH THE NATIONAL BLEND OF MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
LEADING SHALLOW SHORTWAVES MOVING THROUGH THE NORTHERN TIER AND
ASSOCIATED SURFACE SYSTEM REFLECTION AND POSSIBLE FLOW
AMPLIFICATION WITH THE DIGGING OF NORTHERN STREAM UPPER TROUGHING
INTO THE LOWER 48 WILL BRING GROWING PRECIPITATION CHANCES DOWN
FROM THE NORTH-CENTRAL U.S. TO THE GREAT LAKES, OHIO VALLEY, THE
NORTH- CENTRAL APPALACHIANS AND ACROSS THE NORTHERN MID-ATLANTIC
AND NORTHEAST TO INCLUDE MULTIPLE CHANCES FOR ENHANCED SNOW/ICE.
TEMPERATURES WILL CONTINUE TO BE ANOMALOUSLY WARM FROM THE CENTRAL
TO EAST-CENTRAL U.S. MID-LOWER LATITUDES INTO SATURDAY. DAYTIME
HIGHS 25-30+ DEGREES ABOVE NORMAL MAY SET DAYTIME AND WARM MORNING
LOW RECORDS. THE AIRMASS MOVES EAST WITH TIME AND MODERATES. THIS
AIRMASS WILL BE IN STARK CONTRAST WITH SUBSEQUENT COLDER FLOW
SET TO DROP ACROSS THE CENTRAL AND EASTERN U.S. WITH NORTHERN
STREAM UPPER TROUGH AMPLIFICATION AND FRONTAL SYSTEM AND DEEPENED
LOW PASSAGE AND LEADING/WRAPPING ORGANIZED PRECIPITATION. OUT
WEST, TEMPERATURES SHOULD MODERATE TOWARDS NORMAL THIS WEEKEND,
WITH ANOTHER WARMUP POSSIBLE EARLY NEXT WEEK AS UPPER RIDGING
BUILDS IN.
LATER, THERE IS SOME GUIDANCE SIGNAL FAVORING RE-EMERGING HEAVIER
PRECIPITATION CHANCES INTO THE PACIFIC NORTHWEST/NORTHWEST WITH
RENEWED/WINDY ONSHORE FLOW IN ABOUT A WEEK LENDING INTO THE
CLIMATE PREDICTION CENTER'S WEEK 2 FORECAST TO RING IN 2026.
SCHICHTEL
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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