101
FXUS02 KWBC 021855
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
155 PM EST SUN NOV 2 2025
VALID 12Z WED NOV 05 2025 - 12Z SUN NOV 09 2025
..OVERVIEW
THE OVERALL UPPER LEVEL WEATHER PATTERN WILL BE CHARACTERIZED BY
MAINLY ZONAL FLOW WITH SEVERAL PROGRESSIVE TROUGHS/DISTURBANCES
MOVING WEST TO EAST ACROSS THE COUNTRY. THIS PATTERN WILL BRING
SEVERAL LOW PRESSURE SYSTEMS ACROSS THE NORTHERN TIER OF THE NATION
AND SUPPORT PRECIPITATION CHANCES FROM THE NORTHWEST TO THE
NORTHEAST. THE HEAVIEST PRECIPITATION WILL LIKELY FOCUS OVER THE
WEST COAST WHERE PERSISTENT STORMY CONDITIONS ARE EXPECTED AS
PACIFIC LOW PRESSURE SYSTEMS MOVE ONSHORE. THE UPPER LEVEL PATTERN
SHOULD AMPLIFY MORE LATER THIS WEEK AS A STRONGER UPPER LEVEL
LOW/TROUGH APPROACHES THE WEST COAST. PRECIPITATION CHANCES WILL
LIKELY EXPAND INTO MIDWEST AND TENNESSEE VALLEY THEN NORTHEAST
LATER WEEK AS WELL WITH BACK-TO-BACK LOW PRESSURE SYSTEMS MOVING
ACROSS THE REGION. MUCH OF THE SOUTHERN AND CENTRAL U.S. WILL STAY
DRY THIS PERIOD UNDER THE INFLUENCE OF WEAK MEAN RIDGING.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT ON THE OVERALL LARGE SCALE
PATTERN, WITH DIFFERENCES IN THE DETAILS OF INDIVIDUAL SYSTEMS. THE
MOST UNCERTAIN PART OF TODAY'S FORECAST IS THE TIMING OF EACH
FAST-MOVING SYSTEM AS IT MOVES ACROSS THE COUNTRY. RECENT
GFS/CANADIAN MODEL SOLUTIONS HAVE VARIED SOME WITH PROGRESSION,
WHILE ECMWF RUNS HAVE FAVORED SLIGHTLY SLOWER/MORE AMPLIFIED FLOW.
WPC'S FORECAST CONTINUES TO FAVOR A SOLUTION ON THE MORE AMPLIFIED
SIDE OF THE FULL ENVELOPE OF SOLUTIONS, WHICH IS SUPPORTED BY MOST
MACHINE LEARNING GUIDANCE AND TRENDS FROM LATEST 12 UTC GUIDANCE.
ACCORDINGLY, THE WPC MEDIUM RANGE PRODUCT SUITE WAS MAINLY DERIVED
FROM COMPOSITE OF THE GFS/ECMWF, GEFS/ECMWF ENSEMBLE MEANS AND WPC
CONTINUITY TO PROVIDE AS MUCH DETAIL AND CONTINUITY AS REASONABLE
WHILE MITIGATING TIMING DIFFERENCES AS CONSISTENT WITH INDIVIDUAL
SYSTEM PREDICTABILITY. THIS PLAN OVERALL SEEMS IN LINE WITH A NEWER
12 UTC GUIDANCE COMPOSITE AND THE NATIONAL BLEND OF MODELS.
..WEATHER/HAZARDS HIGHLIGHTS
IT GENERALLY REMAINS THE CASE THAT PRECIPITATION CHANCES THIS
PERIOD WILL FOCUS OVER THE NORTHWEST AND NORTHEAST AS A SERIES OF
UPPER TROUGHS AND ACCOMPANYING SURFACE LOW PRESSURE SYSTEMS MOVE
ACROSS THE NORTHERN TIER OF THE COUNTRY. THESE SYSTEMS SHOULD BE
FAIRLY PROGRESSIVE, BUT REPEATED ROUNDS OF RAIN AND MOUNTAIN SNOW
OVER THE TERRAIN ALONG THE WEST COAST COULD RESULT IN LOCALLY HEAVY
PRECIPITATION AMOUNTS. PRECIPITATION RATES WILL LIKELY BE HIGH
ENOUGH ALONG THE COAST FROM NORTHERN CALIFORNIA THROUGH OREGON AND
WASHINGTON TO POSE A RISK OF ISOLATED INSTANCES OF FLASH FLOODING,
ESPECIALLY NEAR STEEP TERRAIN AND BURN SCAR AREAS. THEREFORE, THERE
ARE MARGINAL RISKS OF EXCESSIVE RAINFALL IN EFFECT FOR PORTIONS OF
THE COASTLINE ON WEDNESDAY AND THURSDAY. PRECIPITATION CHANCES
WILL CONTINUE ACROSS THE NORTHWEST THROUGH THE END OF THE WEEK, BUT
PRECIPITATION INTENSITIES ARE FORECAST TO DECREASE.
ELSEWHERE, PRECIPITATION RATES WITH THESE SYSTEMS WILL LIKELY BE
LIGHT TO MODERATE OVER THE INTERIOR NORTHWEST, GREAT LAKES, AND
NORTHEAST, AND THERE WILL BE WINTER WEATHER POTENTIAL IN THE
NORTHERN ROCKIES AND NORTHERN NEW ENGLAND. PERIODS OF MOUNTAIN SNOW
ARE EXPECTED WITH EACH PASSING SYSTEM IN THE NORTHERN ROCKIES, AND
SOME PLOWABLE WRAP AROUND SNOWS WILL BE POSSIBLE ON THE BACKSIDE
OF THESE SYSTEMS LATER THIS WEEK IN NORTHERN NEW ENGLAND.
PRECIPITATION CHANCES WILL EXPAND FROM THE MIDWEST THROUGH THE
TENNESSEE VALLEY LATER THIS WEEK AS THE PATTERN AMPLIFIES AND TWO
BACK-TO-BACK LOW PRESSURE SYSTEMS SWEEP ACROSS THE REGION.
FOR THE SOUTHERN AND CENTRAL U.S., WEAK UPPER LEVEL RIDGING WILL
DOMINATE THE WEATHER PATTERN, KEEPING THE FORECAST MOSTLY DRY,
EXCEPT FOR SOME ISOLATED SHOWER CHANCES OVER THE FLORIDA PENINSULA
AND POSSIBLY SOME SHOWERS IN THE NORTHERN PLAINS LATE THIS WEEK.
RIDGING WILL ALSO RESULT IN ABOVE AVERAGE TEMPERATURES, WITH HIGH
TEMPERATURES FORECAST TO RUN 10-20 DEGREES ABOVE AVERAGE.
ELSEWHERE, TEMPERATURES SHOULD BE NEAR AVERAGE.
DOLAN
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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