337
FXUS02 KWBC 190748
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
348 AM EDT SUN OCT 19 2025
VALID 12Z WED OCT 22 2025 - 12Z SUN OCT 26 2025
..GENERAL OVERVIEW
A WELL DEVELOPED CLOSED LOW NORTH OF THE GREAT LAKES ON WEDNESDAY
WILL SUSTAIN AN OCCLUDED SURFACE LOW WITH A COLD FRONT THAT WILL
EXIT THE COAST ON WEDNESDAY, WITH A RETURN TO COOLER CONDITIONS TO
CLOSE OUT THE WEEK AS CANADIAN HIGH PRESSURE SETTLES INTO THE
REGION. MEANWHILE, A CLOSED UPPER LOW INITIALLY OFF THE COAST OF
CALIFORNIA MOVES INLAND ACROSS THE SOUTHERN ROCKIES AND EVOLVES
INTO AN UPPER TROUGH IN THE SOUTHERN STREAM TO SUPPORT A SURFACE
LOW OVER THE CENTRAL PLAINS WITH INCREASING SHOWERS AND
THUNDERSTORMS. A STRONGER STORM SYSTEM IS LIKELY TO APPROACH THE
PACIFIC NORTHWEST THURSDAY INTO FRIDAY WITH A POTENTIAL ATMOSPHERIC
RIVER AHEAD OF A STRONG COLD FRONT, BRINGING WIDESPREAD RAIN AND
MOUNTAIN SNOW TO CLOSE OUT THE WORK WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE FEATURES GOOD OVERALL SYNOPTIC SCALE
AGREEMENT ACROSS THE CONTINENTAL U.S. THROUGH THE END OF THE WEEK.
HOWEVER, AT THE TIME OF FRONTS/PRESSURES PREPARATION, THE 12Z
CANADIAN MODEL WAS AN OUTLIER SOLUTION WITH RESPECT TO A MUCH
STRONGER LOW OVER THE EASTERN PACIFIC, WHEREAS THE OTHER GUIDANCE
SUPPORTED A WEAKER SOLUTION, SO THE 12Z CMC WAS NOT USED BEYOND
FRIDAY. THE LATEST 00Z CMC RUN DID TREND FAVORABLY WITH THE OTHER
GUIDANCE AND ENSEMBLE MEANS, BUT STILL HAS A SLIGHTLY STRONGER LOW
NEXT WEEKEND WEST OF THE WASHINGTON AND OREGON COASTS. A MULTI-
DETERMINISTIC MODEL BLEND WAS USED AS A STARTING POINT FOR
WEDNESDAY INTO THURSDAY, AND GRADUALLY INCREASED THE ENSEMBLE MEANS
TO ABOUT HALF BY NEXT SUNDAY.
..WEATHER/HAZARDS HIGHLIGHTS
THE WEATHER PATTERN GETS MORE ACTIVE ACROSS THE WEST COAST REGION
GOING INTO THE THURSDAY-FRIDAY TIME PERIOD, AS AN AMPLIFYING TROUGH
AND STRONG COLD FRONT ADVECTS COPIOUS PACIFIC MOISTURE TOWARDS THE
COAST. THIS WILL INITIALLY AFFECT THE WESTERN PORTIONS OF
WASHINGTON AND OREGON THURSDAY NIGHT, WHERE A NEW DAY 5/THURSDAY
MARGINAL RISK AREA IS BEING INTRODUCED, AND THEN NORTHERN
CALIFORNIA GOING INTO FRIDAY, WITH A FEW INCHES OF RAINFALL
POSSIBLE FOR THE COASTAL MOUNTAIN RANGES WITH A POTENTIAL
ATMOSPHERIC RIVER AFFECTING THE REGION. SHOWERS AND STORMS ALSO
INCREASE IN COVERAGE ACROSS THE SOUTH-CENTRAL U.S. BY LATE WEEK AS
WELL IN ASSOCIATION WITH THE SURFACE LOW THAT DEVELOPS. GUIDANCE
HAS CONTINUED TO SHOW A SIGNAL THAT SOME LOCALLY HEAVY RAINFALL MAY
BE POSSIBLE FROM THE SOUTHERN PLAINS TO THE LOWER MISSISSIPPI
VALLEY, AND THEREFORE A MARGINAL RISK OF EXCESSIVE RAINFALL IS NOW
WARRANTED IN THE NEW DAY 5/THURSDAY OUTLOOK FROM CENTRAL KANSAS TO
NORTHWESTERN ARKANSAS. SOME STRONG TO SEVERE THUNDERSTORMS WILL
ALSO BE POSSIBLE IN THIS SAME GENERAL AREA AS INSTABILITY
INCREASES.
HIGH TEMPERATURES ACROSS THE SOUTH-CENTRAL U.S. ARE FORECAST TO
REMAIN ABOVE AVERAGE FOR MID TO LATE WEEK, ESPECIALLY FOR TEXAS
WHERE HIGHS INTO THE 90S MAY TIE/BREAK A FEW DAILY HIGH TEMPERATURE
RECORDS. THERE MAY BE SOME PERIODS OF BELOW AVERAGE TEMPERATURES
FOR THE MIDWEST/NORTHEAST FOLLOWING COLD FRONTAL PASSAGES, THOUGH
HIGHS IN GENERAL LOOK TO REMAIN NEAR AVERAGE THROUGH MUCH OF NEXT
WEEK. THE NORTHERN-TIER FROM THE ROCKIES EAST TO THE PLAINS/UPPER
MIDWEST WILL SEE INCREASINGLY ABOVE AVERAGE HIGHS LATE NEXT WEEK
AND INTO THE WEEKEND AS AN UPPER-RIDGE BUILDS OVERHEAD. THE PACIFIC
SYSTEM WILL BRING COOLER, WELL BELOW AVERAGE TEMPERATURES TO
PORTIONS OF THE WEST COAST BY EARLY NEXT WEEKEND.
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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