854
FXUS02 KWBC 120701
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT THU OCT 12 2023
VALID 12Z SUN OCT 15 2023 - 12Z THU OCT 19 2023
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
MODEL AND ENSEMBLE FORECAST SPREAD OVERALL REMAINS BELOW AVERAGE
SUNDAY INTO TUESDAY IN A PATTERN WITH SEEMINGLY BETTER THAN
AVERAGE PREDICTABILITY. THE WPC PRODUCT SUITE WAS PRIMARILY
DERIVED FROM A BLEND OF THE 12 UTC GFS/ECMWF/CANADIAN/UKMET AND
GEFS/ECMWF ENSEMBLE MEANS ALONG WITH THE COMPATIBLE 01 UTC
NATIONAL BLEND OF MODELS. BLEND WEIGHTING FAVORING THE
DETERMINISTIC MODELS IN THIS PERIOD FOR DETAILS CONSISTENT WITH
PREDICTABILITY WAS SHIFTED INCREASINGLY TO THE ENSEMBLE MEANS AT
LONGER TIME FRAMES AMID GROWING FORECAST SPREAD/UNCERTAINTY. WPC
PRODUCT CONTINUITY IS WELL MAINTAINED. A BLEND OF LATEST 00 UTC
GUIDANCE REMAINS GENERALLY IN LINE WITH THE AFOREMENTIONED
FORECAST PLAN.
..WEATHER/HAZARDS HIGHLIGHTS
A DYNAMIC UPPER TROUGH/CLOSED LOW AND DEEPENED SURFACE LOW/FRONTAL
SYSTEM WILL TRACK THROUGH THE MID-ATLANTIC THIS WEEKEND, LEADING
TO REFORMATION AS A COASTAL LOW/STORM AND MARITIME THREAT BY
SUNDAY. EXPECT ENHANCED WINDS AND LINGERING BUT RELATIVELY
MODEST/LINGERING WRAP-AROUND MOISTURE AND RAINS FAR AROUND THIS
MULTI-PHASED SYSTEM OVER THE EASTERN U.S.. AN INFLUX OF UPPER
ENERGIES WILL CONTINUE TO DIG BACK INTO AN AMPLIFIED/UNSETTLING
MEAN EASTERN CONTINENT UPPER TROUGH POSITION THROUGH EARLY-MID
NEXT WEEK TO THE LEE OF AT LEAST INITIALLY AMPLIFIED/WARMING UPPER
RIDGING FROM THE INTERMOUNTAIN WEST TO THE CANADIAN PRAIRIES.
MEANWHILE UPSTREAM, A COMPLEX SERIES OF SYSTEMS WILL ACT TO
AMPLIFY AN EASTERN PACIFIC UPPER TROUGH POSITION AND WITH GRADUAL
COASTAL INTRUSION TO BRING MOISTURE INLAND TO FUEL MODERATE TO
HEAVY PRECIPITATION FOR THE NORTHWEST, BUT PARTICULARLY FAVORED
SOUTHERN FACING TERRAIN OF THE PACIFIC NORTHWEST/OLYMPICS IN A WET
PERIOD LATE WEEKEND INTO NEXT WEEK. HOWEVER, LOW ENOUGH
PRECIPITATION RATES DO NOT SEEM TO WARRANT AN EXCESSIVE RAINFALL
RISK AREA AT THIS TIME.
THE COLD FRONT SWEEPING ACROSS THE EASTERN U.S. SATURDAY INTO
SUNDAY WILL BRING TEMPERATURES GENERALLY 10 TO 15 DEGREES BELOW
NORMAL, INCLUDING SOUTH FLORIDA WHICH WILL SEE NEAR RECORD HIGH
TEMPERATURES IN THE LOW TO MID 90S THROUGH SATURDAY. MEANWHILE, A
BUILDING RIDGE OVER THE WEST-CENTRAL U.S. BRINGS TEMPERATURES
GENERALLY 5 TO 10 DEGREES ABOVE NORMAL WEST FROM THE ROCKIES TO
THE EASTERN LEE OF THE CASCADES.
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, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES 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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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