243
FXUS02 KWBC 120740
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
340 AM EDT SUN OCT 12 2025
VALID 12Z WED OCT 15 2025 - 12Z SUN OCT 19 2025
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE MODELS REMAIN IN GOOD AGREEMENT AND MULTI-MODEL BLEND SEEMS TO
OFFER A SOLID FORECAST STARTING POINT FOR WEDNESDAY INTO FRIDAY,
ALBEIT WITH A SLIGHLY LESS PROGRESSIVE TREND WITH LATEST 00 UTC
GUIDANCE THAT SEEMS REASONABLE GIVEN THE OVERALL AMPLIFIED FLOW
PATTERN OVER THE NATION. FAVOR A MORE MULTI-MODEL ENSEMBLE MEAN
SOLUTION ALONG WITH BEST COMPATIBLE ECMWF MODEL DETAIL INTO NEXT
WEEKEND AMID GROWING FORECAST SPREAD BUT REASONABLE MACHINE
LEARNING GUIDANCE SUPPORT. THE FLOW IS COMPLICATED BY INCOMING
NORTHERN STREAM SHORTWAVES LATER WEEK INTO NEXT WEEKEND WHICH COULD
MODULATE THE SHAPE/AXIS OF THE TROUGH OR SPLIT IT INTO MULTIPLE
SHORTWAVES AS IS ALSO THE TREND OF LATEST 00 UTC GUIDANCE OVER THE
WEST. OVERALL, THE 01 UTC NBM WAS THE BASIS FOR SENSIBLE WEATHER
GRIDS BUT WITH SOME MODIFICATION TO ACCOUNT FOR THE SLIGHTLY
SLOWER PREFERENCE. IN THE CENTRAL/EASTERN STATES, A SLOWER WESTERN
TROUGH WOULD DELAY THE RIDGE AXIS FROM MOVING EASTWARD, BUT THIS
COULD BE COMPLICATED BY NORTHERN STREAM SHORTWAVES THROUGH EASTERN
CANADA. CONFIDENCE IN THE FORECAST STARTED ABOVE AVERAGE WITH A
TREND TO NEAR/BELOW AVERAGE BY THE END OF THIS FORCAST PERIOD.
..WEATHER/HAZARDS HIGHLIGHTS
A LEAD SHORT RANGE COASTAL STORM WILL BE WORKING WELL OUT TO SEA
ACROSS THE WESTERN ATLANTIC BY MIDWEEK BUT STILL SUPPORT CONTINUED
UNSETTLED/WINDY CONDITIONS OVER NEW ENGLAND THROUGH LATE WEEK AS
IMPULSES DIGGING BEHIND THE SYSTEM BRING SOME LINGERING SHOWERS.
AN INCOMING UPPER LOW/AMPLIFIED TROUGH SLATED TO BRING RAIN/SNOW
TO CALIFORNIA EARLY WEEK WILL LIFT INCREASINGLY INLAND ACROSS THE
WEST/ROCKIES MID-LATE WEEK. A DAY 4/WEDNESDAY WPC EXCESSIVE
RAINFALL OUTLOOK MARGINAL RISK AREA REMAINS OVER NEW MEXICO AND
SOUTHERN COLORADO WHERE LEADING MOISTURE LEVELS MAY FUEL SOME
LINGERING LOCAL DOWNPOURS WITH RUNOFF ISSUES. UPPER SYSTEM AND WAVY
FRONTAL PROGRESION WILL ALSO DRIVE ORGANIZED RAIN/SNOW OVER THE
NORTH-CENTRAL INTERMOUNTAIN WEST/ROCKIES WEDNESDAY/WEDNESDAY
NIGHT. MUCH OF THE WEST WILL SEE AT LEAST SOME RAIN OR SNOW, WITH
SNOW LEVELS LOWERING AS COLDER AIR MOVES IN. TEMPERATURES WILL BE
WELL BELOW NORMAL INTO WEDNESDAY (BY 10-20 DEG) WITH SOME SLIGHT
MODERATION FOR THE REST OF THE WEEK, BUT STILL COOLER THAN
NORMAL. LATER PERIOD, THERE IS ALSO SOME UPSTREAM GUIDANCE SIGNAL
SUPPORTING APPROACH OF ANOTHER AMPLIFIED NORTHEAST PACIFIC STORM
SYSTEM TOWARD THE PACIFIC NORTHWEST/NORTHWEST NEXT WEEKEND THAT MAY
OFFER QUITE UNSETTLED FLOW AND ENHANCED RAINFALL TO MONITOR.
DOWNSTREAM FOR THE CENTRAL STATES, SOUTHWESTERLY UPPER FLOW WILL
INCREASE THE CHANCES OF RAIN FOR MID-LATE WEEK OVER THE NORTHERN
PLAINS INTO THE UPPER MIDWEST CLOSER TO THE JET STREAM WITH WAVY
SURFACE SYSTEM TRANSLATION/GENESIS. MILD AND MORE MOISTURE-LADEN
AIR TO THE SOUTH OVER THE CENTRAL PLAINS AND MID-MISSISSIPPI VALLEY
WILL SUPPORT A GROWING PATTERN WITH SHOWERS AND THUNDERSTORMS
AHEAD OF THE WESTERN/ROCKIES SYSTEM INTO THURSDAY/FRIDAY. ACTIVITY
MAY FLORISH AS FOCUS SHIFTS SLOWLY WITH MORE UNCERTAINTY INTO THE
EAST-CENTRAL STATES INTO NEXT WEEKEND IN AN EMERGING RETURN FLOW
PATTERN TO MONITOR FOR ENHANCED RAINFALL/RUNOFF ISSUE POTENTIAL.
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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