464
FXUS02 KWBC 090700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT SUN OCT 9 2022
VALID 12Z WED OCT 12 2022 - 12Z SUN OCT 16 2022
..GENERAL PATTERN OVERVIEW
AN AMPLIFIED UPPER LEVEL FLOW PATTERN WILL BE IN PLACE FOR THIS
FORECAST PERIOD, WITH A STRONG RIDGE CENTERED NEAR THE WEST COAST
AND A DEEP TROUGH FROM THE PLAINS TO THE EAST COAST. TWO WELL
DEFINED COLD FRONTS ARE EXPECTED TO PASS FROM THE NORTHERN PLAINS
TO THE EASTERN U.S., THUS REINFORCING THE COOL AND AUTUMNAL
AIRMASS WITH GENERALLY BELOW NORMAL TEMPERATURES CONTINUING. A
POTENTIAL HEAVY RAIN AND WIND EVENT IS BECOMING MORE LIKELY FOR
THE NORTHEAST U.S. TO CLOSE OUT THE WORK WEEK AS THE MID-UPPER
LEVEL TROUGH BECOMES NEGATIVELY TILTED, AND LAKE EFFECT/ENHANCED
RAIN/SNOW IS ALSO LIKELY DOWNWIND OF THE GREAT LAKES.
..MODEL AND PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE HAS COME INTO BETTER SYNOPTIC SCALE
AGREEMENT ON THE EVOLVING DEEP TROUGH EXPECTED OVER THE CENTRAL
AND EASTERN U.S., AND THE PROGRESSION OF THE COLD FRONT ACROSS THE
EASTERN U.S. FOR THE WEDNESDAY-FRIDAY TIME PERIOD IS FASTER
COMPARED TO THE PREVIOUS FORECAST. THE CMC HAS ALSO JOINED THE
MODEL CONSENSUS COMPARED TO ITS RUNS OVER THE PAST FEW DAYS. WITH
THE SECOND TROUGH BUILDING IN FOR NEXT WEEKEND, THE ECMWF/CMC HAVE
A STRONGER SIGNAL FOR THIS COMPARED TO THE GFS, ALTHOUGH THE
MODELS AND ENSEMBLES GENERALLY AGREE THAT THE ANOMALOUS TROUGH
PATTERN WILL BE HERE TO STAY FOR A WHILE. THE WPC
FRONTS/PRESSURES FORECAST WAS GENERALLY DERIVED FROM A
MULTI-DETERMINISTIC COMPOSITE ON WEDNESDAY, AND THEN GRADUALLY
INCREASED USE OF THE ENSEMBLE MEANS ALONG WITH SOME PREVIOUS WPC
CONTINUITY AND GFS/ECMWF GOING FORWARD.
..SENSIBLE WEATHER AND POTENTIAL HAZARDS
THE STRONG COLD FRONT AND ASSOCIATED UPPER TROUGH WILL LIKELY
BRING A RETURN TO WIDESPREAD SHOWERS AND STORMS FROM THE CENTRAL
GULF COAST TO THE OHIO VALLEY AND GREAT LAKES ON WEDNESDAY AS
DEEPER MOISTURE IS ADVECTED NORTHWARD. THE COMBINATION OF
INCREASING INSTABILITY AND FAVORABLE KINEMATIC PARAMETERS IN THE
WARM SECTOR MAY LEAD TO SOME STRONG TO SEVERE STORMS FROM
TENNESSEE TO THE OHIO VALLEY ON WEDNESDAY, AND THEN PERHAPS ACROSS
PORTIONS OF THE NORTHEAST ON THURSDAY, ALTHOUGH CONFIDENCE IS
STILL LIMITED ON EXACTLY WHERE THESE STORMS COULD DEVELOP. IN
TERMS OF THE RAINFALL POTENTIAL, THE LATEST NBM HAS SOME AREAL 1-3
INCH RAINFALL TOTALS FROM UPSTATE NEW YORK TO MAINE FOR THE
THURSDAY TO FRIDAY NIGHT TIME PERIOD AS DEEPER ATLANTIC MOISTURE
IS ADVECTED TOWARDS THE NORTHERN APPALACHIANS WITH AN INCREASING
LOW LEVEL JET. A SLIGHT RISK AREA WAS INTRODUCED FOR THE DAY 5
PERIOD FOR THIS REGION, ALTHOUGH DOWNSLOPING FLOW OFF THE HIGHER
TERRAIN IN SOME AREAS MAY LIMIT THE RAINFALL TOTALS IN SOME OF THE
VALLEY LOCATIONS. ELSEWHERE, LAKE ENHANCED RAIN AND SNOW SHOWERS
ARE LIKELY ACROSS PORTIONS OF MICHIGAN, OHIO, PENNSYLVANIA, AND
NEW YORK FOR THE THURSDAY THROUGH SATURDAY TIME PERIOD. MOST OF
THE WESTERN U.S. SHOULD REMAIN DRY WITH PERHAPS A FEW ISOLATED
SHOWERS/STORMS OVER ARIZONA AND NEW MEXICO.
MUCH OF THE NORTHWESTERN U.S. AND CALIFORNIA SHOULD HAVE ABOVE
NORMAL TEMPERATURES EACH DAY WITH THE UPPER RIDGE REMAINING NEARLY
ANCHORED IN PLACE NEAR THE COAST, AND A BRIEF WARM-UP IS LIKELY
FROM THE ARKLATEX REGION TO THE OHIO VALLEY AHEAD OF THE FRONT.
THIS WILL LIKELY BE FOLLOWED BY HIGHS ABOUT 5-15 DEGREES BELOW
AVERAGE TO CLOSE OUT THE WORK WEEK AND GOING INTO NEXT WEEKEND
FROM THE UPPER MIDWEST TO THE OHIO VALLEY AND GREAT LAKES, WITH
HIGHS ONLY IN THE 40S AND 50S FOR MOST OF THESE AREAS.
HAMRICK
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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