132
FXUS02 KWBC 310649
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 AM EDT FRI OCT 31 2025
VALID 12Z MON NOV 03 2025 - 12Z FRI NOV 07 2025
..OVERVIEW
EARLY NEXT WEEK, A DEEP UPPER TROUGH WILL SWING ACROSS THE GREAT
LAKES REGION WHILE A CUTOFF LOW MOVES EAST ACROSS THE SOUTHEAST. IT
IS APPEARING INCREASINGLY LIKELY THAT THE SOUTHERN LOW WILL BE
INFLUENCED BY THE TROUGH AND MOVE FAIRLY QUICKLY OFFSHORE, BUT
THERE IS STILL A CHANCE THAT THE LOW MAY LINGER NEAR THE SOUTHEAST
COAST ON TUESDAY. ANOTHER TROUGH IS EXPECTED TO SWEEP ACROSS THE
GREAT LAKES AND NORTHEAST RIGHT AFTER THE FIRST ONE, WHICH WILL
RESULT IN PERSISTENT PRECIPITATION CHANCES FOR THESE REGIONS
THROUGH MOST OF NEXT WEEK. MEANWHILE, A STORMY PATTERN WILL DEVELOP
IN THE WEST AS A SERIES OF PACIFIC FRONTAL SYSTEMS BRING
WIDESPREAD PRECIPITATION CHANCES TO THE REGION, WITH HEAVY
PRECIPITATION POTENTIAL ALONG THE WEST COAST. MEAN RIDGING WILL
DOMINATE THE WEATHER PATTERN FOR MUCH OF THE CENTRAL U.S. AND
SOUTHWEST.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE HAS BEEN QUITE UNCERTAIN ABOUT THE EVOLUTION OF THE
NORTHEASTERN TROUGH AND UPPER LOW OVER THE SOUTHEAST EARLY NEXT
WEEK, WHICH IS THE MOST UNCERTAIN PART OF TODAY'S FORECAST. SOME
SOLUTIONS HAVE SHOWN LITTLE INTERACTION BETWEEN THE TWO FEATURES,
RESULTING IN THE CLOSED LOW LINGERING LONGER AND DRIFTING FURTHER
SOUTH OVER THE SOUTHEAST, BUT SOME HAVE SHOWN THE LOW BEING SWEPT
QUICKLY OFFSHORE BY THE TROUGH. THE MAJORITY OF THE AVAILABLE
DETERMINISTIC MODEL SOLUTIONS, INCLUDING THE EC-AIFS, ARE NOW
FAVORING THE QUICKER SOLUTION. THE GFS SEEMS TO BE THE ONLY OUTLIER
WITH A SLOWER SOLUTION. GIVEN THIS, WPC'S FORECAST REFLECTS A
FASTER SOLUTION. MODEL AGREEMENT SURPRISINGLY INCREASES FOR THE
SECOND HALF OF NEXT WEEK AS A SERIES OF STRONGER PACIFIC
TROUGHS/FRONTAL SYSTEMS MOVE INTO THE WEST.
WPC'S FORECAST BLEND FOR EARLY NEXT WEEK WAS COMPOSED OF 70%
DETERMINISTIC GUIDANCE, WITH A PREFERENCE TOWARDS THE ECMWF AND CMC
OVER THE GFS, AND 30% ENSEMBLE MEAN GUIDANCE FROM THE GEFS AND
ECENS. FOR THE SECOND HALF OF THE WEEK, THE INFLUENCE FROM THE
ENSEMBLE MEANS WAS INCREASED TO 50-60% TO ACCOUNT FOR USUAL MODEL
SPREAD AT THIS TIME FRAME, AND THE REST OF THE BLEND WAS COMPOSED
OF DETERMINISTIC GUIDANCE FROM THE ECMWF, CMC, AND GFS.
..WEATHER/HAZARDS HIGHLIGHTS
PRECIPITATION CHANCES WILL FOCUS IN THE EAST AND WEST WHILE THE
CENTRAL U.S. REMAINS FAIRLY DRY NEXT WEEK. UPPER LEVEL TROUGHING
WILL SUPPORT PERSISTENT PERIODS OF PRECIPITATION THROUGHOUT THE
WEEK FOR THE GREAT LAKES AND NORTHEAST AS A FEW FRONTAL SYSTEMS
MOVE ACROSS THESE REGIONS. THESE SYSTEMS SHOULD BE PROGRESSIVE,
WHICH WILL LIMIT THE CHANCE OF ANY HEAVY PRECIPITATION. A CLOSED
LOW OVER THE SOUTHEAST WILL ALSO SUPPORT LIGHT TO MODERATE RAIN
SHOWERS EARLY NEXT WEEK. RAINFALL TOTALS WILL ULTIMATELY DEPEND ON
THE SPEED AND DURATION OF THIS SYSTEM, BUT IT LOOKS INCREASINGLY
LIKELY THAT THE LOW WILL MOVE QUICKLY INTO THE ATLANTIC, LIMITING
RAINFALL POTENTIAL.
AN UNSETTLED WEATHER PATTERN WILL DEVELOP IN THE WEST NEXT WEEK AS
SEVERAL RELATIVELY STRONGER SYSTEMS MOVE ONSHORE FROM THE PACIFIC.
WIDESPREAD PRECIPITATION CHANCES ARE EXPECTED ACROSS THE PACIFIC
NORTHWEST AND NORTHERN CALIFORNIA THROUGH THE WEEK. THE HEAVIEST
PRECIPITATION IS EXPECTED TO FOCUS OVER NORTHERN CALIFORNIA AND
SOUTHWESTERN OREGON AS AN ATMOSPHERIC RIVER EVENT UNFOLDS TUESDAY
INTO WEDNESDAY. MOST PRECIPITATION SHOULD FALL AS RAIN WITH THIS
EVENT BUT HEAVY SNOW WILL BE POSSIBLE IN THE HIGHER ELEVATIONS OF
THE SIERRA NEVADA. A MARGINAL RISK OF EXCESSIVE RAINFALL HAS BEEN
INTRODUCED IN THE DAY 5/TUESDAY EXCESSIVE RAINFALL OUTLOOK,
REPRESENTING A RISK FOR ISOLATED FLASH FLOODING WITH HEAVY RAIN
ALONG THE COAST. THE SYSTEM RESPONSIBLE FOR THIS EVENT SHOULD MOVE
QUICKLY INLAND, WHICH WILL HELP TO LIMIT PRECIPITATION TOTALS.
ANOTHER SYSTEM WILL APPROACH THE PACIFIC NORTHWEST THURSDAY INTO
FRIDAY, WHICH SHOULD BRING ANOTHER SHOT OF POTENTIALLY HEAVY
PRECIPITATION, WITH LOW ELEVATION RAIN AND MOUNTAIN SNOW, TO
WESTERN WASHINGTON AND OREGON, AND THE NORTHERN ROCKIES MAY SEE
SOME SNOW AS WELL.
ABOVE AVERAGE TEMPERATURES ARE FORECAST FROM THE SOUTHWEST TO THE
PLAINS THROUGH MUCH OF NEXT WEEK UNDER THE INFLUENCE OF UPPER
LEVEL RIDGING. HIGH TEMPERATURES ARE FORECAST TO RUN 10-20 DEGREES
ABOVE AVERAGE. ELSEWHERE, TEMPERATURES SHOULD BE NEAR TO SLIGHTLY
BELOW 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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