323
FXUS02 KWBC 100700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
259 AM EDT MON OCT 10 2022
VALID 12Z THU OCT 13 2022 - 12Z MON OCT 17 2022
***HEAVY RAIN AND GUSTY WINDS ARE LIKELY THURSDAY-FRIDAY IN THE
NORTHEAST AHEAD OF A STRONG COLD FRONT***
..PATTERN OVERVIEW
A MORE ACTIVE FALL WEATHER PATTERN IS EXPECTED TO EVOLVE BY THE
END OF THIS WEEK AND CONTINUING INTO THE WEEKEND AS A COUPLE OF
COLD FRONTS ASSOCIATED WITH AMPLIFYING UPPER LEVEL
TROUGHS/SHORTWAVES MOVE ACROSS THE CENTRAL AND EASTERN STATES.
THE FIRST COLD FRONT WILL BE CROSSING THE APPALACHIANS BY EARLY
THURSDAY WITH WIDESPREAD SHOWERS AND STORMS LIKELY AHEAD OF IT
ACROSS THE EAST COAST REGION AND HEAVY RAIN AND WIND FOR PORTIONS
OF THE NORTHEAST. BY THIS WEEKEND, A SECOND COLD FRONT DROPPING
SOUTHWARD FROM CANADA IS EXPECTED TO REINFORCE THE COOL AIRMASS
ACROSS THE EASTERN HALF OF THE NATION. THE OPPOSITE IS EXPECTED
TO BE THE CASE ACROSS THE WEST COAST REGION AS A UPPER RIDGE AND
MOSTLY SUNNY SKIES WILL PREVAIL AND LEAD TO SEPTEMBER-LIKE
TEMPERATURES FROM CALIFORNIA TO THE PACIFIC NORTHWEST.
..MODEL AND PREDICTABILITY ASSESSMENT
THE 00Z MODEL GUIDANCE SUITE HAS A VERY GOOD DEPICTION OF THE MAIN
SYNOPTIC SCALE FEATURES ACROSS THE NATION TO CLOSE OUT THE WORK
WEEK, WHICH INCLUDES A REX BLOCK NEAR THE WEST COAST AND A BIG
TROUGH BUILDING OVER THE EAST-CENTRAL U.S. MODEL AGREEMENT IS
STILL GOOD GOING INTO SATURDAY, ALTHOUGH SOME DIFFERENCES EMERGE
OVER SOUTHERN CANADA THAT COULD AFFECT THE TIMING AND STRENGTH OF
THE SECOND COLD FRONT THAT WILL REINFORCE THE COOL AIRMASS ALREADY
IN PLACE, WITH THE GFS INDICATING A BROADER CLOSED LOW WHEREAS THE
CMC/ECMWF INDICATE A SLIGHTLY MORE DEFINED SHORTWAVE THAT WILL
THEN MERGE WITH THE MAIN TROUGH AXIS. OVERALL, THE DECREASE IN
MODEL/ENSEMBLE SPREAD HAS IMPROVED NICELY OVER THE PAST COUPLE OF
DAYS.
IN TERMS OF PREFERENCES FOR FRONTS/PRESSURES, A
MULTI-DETERMINISTIC MODEL BLEND WORKS QUITE WELL AS A STARTING
POINT IN THE FORECAST PROCESS FOR BOTH THURSDAY AND FRIDAY WITH
ABOVE AVERAGE CONFIDENCE ON THE SYNOPTIC SCALE LEVEL, AND THEN
INCORPORATING SOME OF THE ENSEMBLE MEANS GOING INTO THE SATURDAY
THROUGH MONDAY TIME PERIOD.
..SENSIBLE WEATHER AND POTENTIAL HAZARDS
THE FIRST STRONG COLD FRONT AND THE ASSOCIATED UPPER TROUGH WILL
BRING A RETURN TO WIDESPREAD SHOWERS AND STORMS FROM THE
MID-ATLANTIC TO THE NORTHEAST ON THURSDAY. RAINFALL AMOUNTS ARE
LIKELY TO BE HIGHEST IN THE INTERIOR NORTHEAST THURSDAY AND
CONTINUING INTO FRIDAY ACROSS MAINE AS DEEPER ATLANTIC MOISTURE IS
ADVECTED TOWARDS THE NORTHERN APPALACHIANS WITH AN INCREASING LOW
LEVEL JET AND ANOMALOUSLY HIGH PWS. A SLIGHT RISK AREA REMAINS IN
PLACE IN WPC'S EXPERIMENTAL DAY 4 EXCESSIVE RAINFALL OUTLOOK FOR
THIS REGION. TERRAIN COULD ENHANCE RAIN TOTALS ACROSS THE
ADIRONDACKS AND THE WHITE AND GREEN MOUNTAINS, BUT LOWER
ELEVATIONS COULD SEE HEAVY RAINFALL AS WELL WITH A BROAD RISK FOR
SOME FLOODING. IF THE HEAVIER RAINFALL RATES ARE MORE LIMITED,
THEN THE FLOODING POTENTIAL SHOULD BE MITIGATED SOME. STRONG AND
GUSTY WINDS ARE ALSO A CONCERN THERE AS THE TROUGH BECOMES
NEGATIVELY TILTED AND THE PRESSURE GRADIENT TIGHTENS. ELSEWHERE,
LAKE ENHANCED RAIN AND SNOW SHOWERS ARE LIKELY FOR THE THURSDAY
THROUGH SATURDAY TIME PERIOD, AND SHOWERS COULD BECOME MORE
WIDESPREAD WITH ANOTHER FRONTAL SYSTEM BY SUNDAY. MOST OF THE WEST
SHOULD REMAIN DRY THROUGH THE LATTER PART OF THE WEEK WITH PERHAPS
A FEW ISOLATED SHOWERS/STORMS OVER ARIZONA AND NEW MEXICO INTO
TEXAS, WITH COVERAGE POSSIBLY INCREASING NEXT WEEKEND AS THE UPPER
LOW SLOWLY MOVES TO THE EAST ACROSS THE DESERT SOUTHWEST.
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. THE OPPOSITE WILL HOLD TRUE
ACROSS THE NORTH-CENTRAL U.S. AND EXTENDING TO THE EAST COAST,
WITH HIGHS ABOUT 5-15 DEGREES BELOW AVERAGE TO CLOSE OUT THE
WORKWEEK AND GOING INTO NEXT WEEKEND, WITH HIGHS ONLY IN THE 40S
AND 50S FROM THE GREAT LAKES TO THE NORTHEAST ON MOST DAYS.
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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