480
FXUS02 KWBC 270652
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 AM EDT THU OCT 27 2022
VALID 12Z SUN OCT 30 2022 - 12Z THU NOV 03 2022
...PACIFIC NORTHWEST HEAVY RAINS AND NORTHWEST TO GREAT
BASIN/ROCKIES HEAVY MOUNTAIN SNOW THREAT NEXT WEEK...
..GUIDANCE AND PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
COMPOSITE OF REASONABLY WELL CLUSTERED GUIDANCE FROM THE 18 UTC
GFS AND 12 UTC ECMWF/UKMET/CANADIAN FOR SUNDAY ALONG WITH
COMPATIBLE INPUT FROM THE 01 UTC NATIONAL BLEND OF MODELS (NBM)
AND WPC CONTINUITY. 00 UTC MODEL AND ENSEMBLE GUIDANCE REMAINS IN
AGREEMENT.
AMPLE PACIFIC SYSTEM ENERGIES ARE SET TO WORK INTO THE
NORTHWEST/WEST THROUGH MEDIUM RANGE TIME SCALES, BUT LARGE FLOW
DIFFERENCES AGAIN GROW MORE THAN USUAL EARLY NEXT WEEK AND
STEADILY TRANSLATE DOWNSTREAM OVER THE REST OF THE LOWER 48. 12/18
UTC GFS RUNS OFFER A WESTERN U.S. UPPER TROUGH SOLUTION ON THE
AMPLIFIED SIDE OF GUIDANCE OVER TIME IN STARK CONTRAST TO A
SEEMINGLY OUTLIER FLATTER 12 UTC ECMWF. ENSEMBLE MEANS SUPPORT
TROUGH AMPLIFICATION 3/4 OF THE WAY TOWARD THE GFS. THIS SEEMS
REASONABLE CONSIDERING UPPER RIDGE AMPLIFICATION POTENTIAL
UPSTREAM OVER THE PACIFIC, BUT COGNIZANT OF FORECAST SPREAD. THE
MOST COMPATIBLE 12 UTC NAEFS/ECMWF ENSEMBLE MEANS SEEM TO OFFER A
GOOD AND CONSISTENT FORECAST BASIS ACROSS MUCH OF THE LOWER 48
NEXT WEEK. LATEST 00 UTC MODEL GUIDANCE OFFERS HOPE FOR IMPROVING
FORECAST CONFIDENCE NEXT WEEK AS ATROCIOUS RUN TO RUN CONTINUITY
IN BOTH THE UKMET AND ECMWF NOW SHOW A SUBSTANTIAL TREND TO THE
FAVORED NAEFS/ECMWF ENSEMBLE MEANS.
..PATTERN OVERVIEW AND WEATHER/HAZARD HIGHLIGHTS
EXPECT FAVORABLE DYNAMICS AND MOISTURE TO FUEL PERIODS OF MODERATE
TO LOCALLY ENHANCED PRECIPITATION WITH OVERALL FOCUS LIKELY TO
GRADUALLY SPREAD OUT FROM THE PACIFIC NORTHWEST INTO CALIFORNIA
AND FARTHER INLAND ACROSS THE NORTH-CENTRAL GREAT BASIN/ROCKIES
NEXT WEEK WITH FLOW AMPLIFICATION. THIS WILL OFFER HEAVIEST
RAINFALL POTENTIAL FOR THE COASTAL RANGES/OLYMPICS AND CASCADES OF
THE PACIFIC NORTHWEST STARTING THIS WEEKEND ALONG WITH A THREAT
FOR HEAVY MOUNTAIN SNOWS SET TO ALSO SPREAD NEXT WEEK INTO
CALIFORNIA AND ACROSS THE NORTH-CENTRAL GREAT BASIN/ROCKIES AS
DEPICTED IN THE WPC WINTER WEATHER OUTLOOK PROBABILITIES.
SOUTHERN STREAM SYSTEM ENERGIES WILL LIFT A SWATH OF RAINFALL
THROUGH THE LENGTH OF THE EAST-CENTRAL U.S. SUNDAY INTO EARLY NEXT
WEEK TO INCLUDE A MODERATELY HEAVY RAINFALL FOCUS ACROSS THE UPPER
OHIO VALLEY AND APPALACHIANS TO THE MID-ATLANTIC/NORTHEAST FOR
HALLOWEEN AS LEAD SYSTEM AND UPSTREAM UPPER TROUGH ENERGY
REINFORCEMENT WORK INTO BLOCKY LEAD RIDGING. EXPECT MODEST COASTAL
TRIPLE POINT GENESIS MAY FOCUS SOME ATLANTIC MOISTURE TO
SUPPLEMENT LINGERING GULF MOISTURE.
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, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE
AT:
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
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