103
FXUS02 KWBC 260709
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
308 AM EDT WED OCT 26 2022
VALID 12Z SAT OCT 29 2022 - 12Z WED NOV 02 2022
...HEAVY RAIN/SNOW THREAT FOR THE NORTHWEST/ROCKIES SUNDAY THROUGH
EARLY NEXT WEEK...
...WEEKEND CLOSED LOW HEAVY RAIN THREAT FROM THE LOWER MISSISSIPPI
VALLEY THROUGH THE SOUTHERN APPALACHIANS...
..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 THIS WEEKEND ALONG WITH
COMPATIBLE INPUT FROM THE 01 UTC NATIONAL BLEND OF MODELS (NBM)
AND WPC CONTINUITY. LATEST 00 UTC MODEL AND ENSEMBLE GUIDANCE
STILL SEEMS BROADLY IN LINE DURING THIS PERIOD FORECAST IN A
PATTERN WITH SEEMINGLY ABOVE NORMAL PREDICTABILITY. AS HAS BEEN
THE CASE RECENTLY, FORECAST SPREAD GROWS STEADILY BY LATER DAY
4/DAY 5, ABOUT A DAY EARLIER THAN THE NORM. ACCORDINGLY, PREFER A
SOLUTION CLOSEST TO THE COMPATIBLE GEFS/ECMWF ENSEMBLE MEANS THAT
PROVIDE DECENT PRODUCT CONTINUITY INTO NEXT WEEK VERSUS CHASING
RUN TO RUN FLOW VARIED SYSTEMS IN THE DETERMINISTIC MODEL GUIDANCE.
..PATTERN OVERVIEW AND WEATHER/HAZARD HIGHLIGHTS
THE DETAILS WITH A POTENT SERIES OF PACIFIC SYSTEMS TO WORK INTO
THE WEST/NORTHWEST THIS WEEKEND AND THROUGH EARLY-MID NEXT WEEK
REMAINS MORE RUN TO RUN VARIED THAN NORMAL IN RECENT MODEL
GUIDANCE, BUT THE COMPATIBLE GEFS/ECMWF ENSEMBLE MEANS OFFER A
INCREASINGLY STRONG SIGNAL FOR A PATTERN WITH LONG FETCH MOISTURE
TO FUEL PERIODIC MODERATE TO LOCALLY ENHANCED PRECIPITATION FROM
NORTHERN CALIFORNIA AND THE PACIFIC NORTHWEST INLAND ACROSS THE
NORTH-CENTRAL GREAT BASIN/ROCKIES. THIS WILL OFFER HEAVIEST
RAINFALL POTENTIAL FOR THE COASTAL RANGES/OLYMPICS AND CASCADES OF
THE PACIFIC NORTHWEST ALONG WITH A SIGNIFCIANT THREAT FOR TERRAIN
ENHANCED ELEVATION SNOW SET TO ALSO SPREAD EARLY-MID NEXT WEEK
INTO THE MOUNTAINS OF NORTHERN CALIFORNIA INLAND ACROSS THE
NORTH-CENTRAL GREAT BASIN/ROCKIES AS DEPICTED IN THE WPC WINTER
WEATHER OUTLOOK PROBABILITIES IN NDFD.
MEANWHILE, AN INTIALLY CLOSED/SEPARATED SOUTHERN STREAM SYSTEM IS
SLATED TO LIFT FROM THE SOUTHERN PLAINS THROUGH THE OHIO VALLEY
THIS WEEKEND. THIS WILL ACT TO FOCUS ACROSS THE SOUTH ENHANCED
RAIN/CONVECTION GIVEN UPPER AND SURFACE SYSTEM SUPPORT TO POOL
MOISTURE/INSTABILITY TO FUEL ACTIVITY. THERE IS A SOME GUIDANCE
SIGNAL FOR LOCALLY MODERATE TO HEAVY RAINFALL GIVEN THE RISK OF
REPEAT/TRAINING CELLS WITH OVERALL SLOW SYSTEM TRANSLATION, ALBEIT
WITH DETAILS LESS CERTAIN GIVEN THE NATURE OF CLOSED FEATURES. A
WPC EXPERIMENTAL MED-RANGE ERO CONSIDERED A "SLIGHT" RISK OF
EXCESSIVE RAINFALL FOR THE CENTRAL GULF COAST STATES SATURDAY, BUT
HELD OFF FOR NOW GIVEN UNCERTAINTIES WITH CONVECTIVE DETAILS AND
ANTECEDENT CONDITIONS. NEVERTHELESS, ALSO EXPECT A SWATH OF
MODERATELY HEAVY RAINFALL TO LIFT ACROSS THE OHIO
VALLEY/APPALACHAINS AND ACROSS THE EASTERN SEABOARD THROUGH EARLY
NEXT WEEK WITH THE LEAD SYSTEM AND WITH REJUVINATING BACKSIDE
UPPER TROUGH ENERGY FEED THAT MAY SPAWN MODEST COASTAL/FRONTAL
GENESIS AND MOISTURE FROM THE ATLANTIC IN ADDITION TO 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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