868
FXUS02 KWBC 271850
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 PM 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 DETERMINISTIC GUIDANCE DAYS
3-5, WITH MORE INCORPORATION OF THE ENSEMBLE MEANS DAYS 6-7 GIVEN
INCREASED FORECAST SPREAD, AS DESCRIBED BELOW. THIS MAINTAINS GOOD
CONTINUITY WITH THE PREVIOUS WPC FORECAST AS WELL.
AMPLE PACIFIC SYSTEM ENERGIES ARE SET TO WORK INTO THE
NORTHWEST/WEST THROUGH MEDIUM RANGE TIME SCALES, WITH SOME
CONTINUED UNCERTAINTY BY MID NEXT WEEK. THE LATEST GFS RUNS HAVE
BEEN CONSISTENT IN SHOWING A MORE AMPLIFIED SOLUTION, BUT THE 00Z
ECMWF RUN TODAY TRENDED IN THAT MORE AMPLIFIED DIRECTION AS WELL.
MAIN DIFFERENCES SURROUNDING THIS DEEP TROUGH ARE NOW TIED MORE TO
TIMING, WITH THE GFS/GEFS SLOWER THAN THE ECMWF/ECENS AND CMC.
WPCS FORECAST TODAY FAVORED A MORE MIDDLE GROUND SOLUTION RIGHT
NOW. ONLY OTHER THING TO NOTE ACROSS THE CONUS WITH THE PATTERN IS
A FEW SHORTWAVES MOVING FROM THE SOUTHERN PLAINS INTO THE
MID-ATLANTIC/NORTHEAST WHICH SHOW TYPICAL MEDIUM RANGE TIME SCALE
DIFFERENCES AND A GENERAL MODEL BLEND SEEMS TO WORK WELL.
..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.
TEMPERATURES ACROSS THE ENTIRE WESTERN U.S. WILL TREND MUCH COLDER
AS THE TROUGH AMPLIFIES ALONG THE COAST NEXT WEEK. DAYTIME HIGHS
IN MANY LOCATIONS COULD BE 10 TO 20 DEGREES BELOW NORMAL.
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 MODERATE TO LOCALLY 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.
TEMPERATURES BEHIND AND TO THE NORTH OF THIS SYSTEM SHOULD TREND
WARMER ACROSS THE NORTH-CENTRAL U.S. THROUGH THE PERIOD AS UPPER
RIDGING MOVES THROUGH.
SANTORELLI/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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