366
FXUS02 KWBC 200636
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
136 AM EST THU FEB 20 2025
VALID 12Z SUN FEB 23 2025 - 12Z THU FEB 27 2025
..WET PACIFIC NORTHWEST PATTERN THIS WEEKEND/EARLY NEXT WEEK
..OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL AND ENSEMBLE FORECAST SPREAD HAS DECREASED SOME OVER THE
LAST FEW CYCLES IN A MEDIUM RANGE PATTERN NOW WITH AT LEAST AVERAGE
PREDICTABILITY OVERALL. THERE REMAINS A COMMON FLOW EVOLUTION
SIGNAL TOWARD A LARGER SCALE MEAN UPPER PATTERN HIGHLIGHTED INTO
NEXT WEEK BY A WESTERN RIDGE AND EASTERN TROUGH. THIS IS WELL
SUPPORTED BY MACHINE LEARNING MODELS AND WILL FOCUS MODERATE TO
HEAVIER PRECIPITATION INTO THE PACIFIC NORTHWEST, ALONG WITH A
PRONOUNCED WARMING TREND FROM WEST TO EAST OVER THE LOWER 48.
ACCORDINGLY, THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY
DERIVED FROM A PREFERRED BLEND OF THE MODELS AND ENSEMBLES WITH
MAJORITY WEIGHTING IN THE BLEND APPLIED TO THE MODELS VALID FOR
SUNDAY INTO TUESDAY, AND THEN THE ENSEMBLE MEANS INTO MID-LATER
NEXT WEEK AMID RELATIVELY SLOWLY GROWING SYSTEM VARIANCES. THIS
SOLUTION MAINTAINS REASONABLY GOOD CONTINUITY.
..WEATHER/HAZARDS HIGHLIGHTS
IT REMAINS THE CASE THAT ABOVE AVERAGE TEMPERATURES WILL DEVELOP
OVER THE WEST THEN FOR MUCH OF CENTRAL U.S. WHERE BY EARLY NEXT
WEEK MOST LOCATIONS WEST OF THE MISSISSIPPI RIVER WILL WARM TO MUCH
ABOVE NORMAL WITH DECENT COVERAGE OF PLUS 10-25 DEGREE ANOMALIES.
BEST POTENTIAL FOR HIGHEST ANOMALIES WILL BE NEAR THE NORTHERN
PLAINS. THE EAST SHOULD ALSO WARM TO ABOVE NORMAL NEXT WEEK.
GUIDANCE CONTINUES TO OFFER A STRONG SIGNAL FOR A PATTERN FAVORING
A LONGER FETCH MOISTURE FEED TO FUEL MODERATE TO HEAVY LOWER
ELEVATION RAIN AND HIGH ELEVATION/MOUNTAIN SNOW INTO THE PACIFIC
NORTHWEST THIS WEEKEND INTO EARLY NEXT WEEK. ENHANCED SNOWS WILL
ALSO WORK INLAND OVER THE NORTHERN INTERMOUNTAIN WEST/ROCKIES WITH
DOWNSTREAM SYSTEM TRANSLATION. EXPECT HIGHEST PRECIPITATION TOTALS
EXISTS OVER THE FAVORED TERRAIN AND COASTAL AREAS OF WESTERN
WASHINGTON/OREGON AND INTO NORTHWEST CALIFORNIA. THE DAYS 4/5 WPC
EXCESSIVE RAINFALL OUTLOOKS VALID FOR SUNDAY AND MONDAY EACH SHOW A
MARGINAL RISK THREAT AREA GIVEN THE CUMULATIVE EFFECT OF THE
MULTI-DAY EPISODE. THE NORTHWEST SHOULD TREND DRIER MIDWEEK AS A
DYMANIC MONDAY- TUESDAY SYSTEM DEPARTS AND UPPER RIDGING BUILDS IN.
DOWNSTREAM, SHORTWAVE ENERGY EJECTING FROM THE SOUTHERN ROCKIES
OUT FROM THE WEEKEND AND MAY SUPPORT PERIODS OF MODERATE RAINFALL
OVER THE GULF AND POSSIBLY INLAND INTO THE GULF COAST STATES AND
SOUTHEAST TO THE NORTH OF A WAVY FRONTAL ZONES. MOST GUIDANCE HOLDS
MAIN INSTABILITY OVER THE GULF. MOST PRECIPITATION SHOULD BE RAIN,
THOUGH A LITTLE WINTRY WEATHER COULD BE POSSIBLE IN THE NORTHERN
FRINGE OF THE MOISTURE SHIELD EARLY PERIOD IF IT EXTENDS FAR
ENOUGH NORTH BEFORE THE AIRMASS MODERATES. SURFACE WAVE/FRONTAL
DETAILS OVER THE GULF AND THE WESTERN ATLANTIC REMAIN QUITE
UNCERTAIN FOR DETAILS INTO NEXT WEEK. HOWEVER FEATURES MAY EVOLVE,
WAVES SHOULD BE RELATIVELY WEAK AND MOST PRECIPITATION SHOULD STAY
OFFSHORE THE MID- ATLANTIC/NEW ENGLAND. DIGGING OF NORTHERN STREAM
SHORTWAVE ENERGY THIS WEEKEND INTO EARLY NEXT WEEK WILL SPREAD
LIGHT-SIDE PRECIPITATION (MOSTLY SNOW) FROM THE GREAT LAKES REGION
THROUGH NEW ENGLAND. LATEST GUIDANCE IS NOT TOO ENTHUSIASTIC ABOUT
POTENTIAL FOR WRAPBACK COASTAL LOW LINKAGE OVER THE NORTHEAST TO
ENHANCE ACTIVITY EARLY- MID NEXT WEEK, BUT IT REMAINS WORTH
MONITORING IN FUTURE RUNS. MODERATE CYCLOGENEIS AND FRONTOGENESIS
MAY DEVELOP OVER THE PLAINS/MISSISSIPPI VALLEY NEXT WEDNESDAY AND
WORK OVER THE EAST- CENTRAL U.S. BY THURSDAY. THE WARMER PATTERN BY
THEN SHOULD MOSTLY FAVOR AN EMERGING AREA OF MODERATE WRAPPING
RAINS WITH RETURN GULF MOISTURE FLOW ASIDE FROM A LITTLE WINTRY
WEATHER ON THE FAR NORTH COOL SIDE OF THE LOW.
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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