747
FXUS02 KWBC 151900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 PM EST FRI NOV 15 2024
VALID 12Z MON NOV 18 2024 - 12Z FRI NOV 22 2024
...HEAVY RAINFALL/RUNOFF AND SEVERE WEATHER/HIGH WIND THREATS FOR
PORTIONS OF THE COOLING CENTRAL U.S. EARLY NEXT WEEK...
..EXCESSIVE RAINFALL/RUNOFF THREAT FOR THE CENTRAL GULF COAST
..OVERVIEW
QUITE AN ACTIVE WEATHER PATTERN IS EXPECTED TO BE IN PLACE ACROSS
THE CONTINENTAL U.S. AND VICINITY NEXT WEEK. AMPLE UPPER TROUGH
ENERGIES EJECTING OVER THE CENTRAL U.S. WILL SPAWN CYCLOGENESIS
ACROSS THE PLAINS TO PRODUCE A WIDE SWATH OF MODERATE TO HEAVY
RAINFALL/CONVECTION FROM TEXAS TO THE UPPER MIDWEST EARLY NEXT
WEEK. THIS WILL ALSO OFFER HIGH WINDS AND SOME SNOW POTENTIAL ON
THE COOLING BACKSIDE OVER THE SYSTEM. A LARGE CUT-OFF UPPER LOW
LIKELY TO DEVELOP OVER THE GREAT LAKES AND OHIO VALLEY REGION BY
THE SECOND HALF OF THE WEEK, WITH COLDER WEATHER MOVING IN ACROSS
THIS REGION ALONG WITH A CIRCULATION WRAPPING RAINS AND SOME SNOWS
ON TAP LATER BEXT WEEK WORKING FROM THE GREAT LAKES TO PORTIONS OF
THE APPALACHIANS/NORTHEAST. IN TERMS OF THE TROPICS, ALTHOUGH
CURRENT TROPICAL STORM SARA WILL LIKELY REMAIN WELL TO THE SOUTH
ACROSS CENTRAL AMERICA AND THE FAR SOUTHERN GULF OF MEXICO, A PLUME
OF ENHANCED TROPICAL MOISTURE IS LIKELY TO ADVECT NORTHWARD ACROSS
THE GULF AND BRING THE POTENTIAL FOR HEAVY RAIN/RUNOFF ISSUES
AHEAD OF AN APPROACHING COLD FRONT FROM THE CENTRAL GULF COAST TO
FLORIDA. MEANWHILE, EXPECT A MULTI-DAY HEAVY RAIN AND MOUNTAIN
SNOW PATTERN TO DEVELOP FOR THE PACIFIC NORTHWEST NEXT WEEK AS AN
ATMOSPHERIC RIVER FEEDS INLAND IN ADVANCE OF DEEP PACIFIC STORM
SYSTEMS APPROACHING THE REGION.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST 00/06/12 UTC MODELS AND ENSEMBLES HAVE CONVERGED UPON A
REASONABLY WELL CLUSTERED SOLUTION OVER MEDIUM RANGE TIME SCALES
FOR MUCH OF THE FORECAST DOMAIN. THIS PORTENDS IMPROVED
PREDICTABILITY, ALBEIT IN THIS CASE TEMPERED BY PRIOR SIGNIFICANT
CYCLE TO CYCLE CONTINUITY ISSUES. PREFER A COMPOSITE MODEL AND
ENSEMBLE SOLUTION AS GENERALLY IN LINE WITH THE NATIONAL BLEND OF
MODELS. THIS SOLUTION IS ALSO BOLSTERED GIVEN QUITE FAVORABLE
SUPPORT FROM AIFS AND GRAPHCAST/FOURCAST/PANGU WEATHER MACHINE
LEARNING MODELS. THE FUXI HAS NOT BEEN AVAILABLE SINCE THE
NOVEMBER 12 UPGRADE OF THE ECMWF SYSTEM.
..WEATHER/HAZARDS HIGHLIGHTS
THE DAY 4/MONDAY WPC EXCESSIVE RAINFALL OUTLOOK (ERO) SHOWS A
BROAD MARGINAL RISK AREA FROM NORTH TEXAS TO SOUTHERN MINNESOTA
GIVEN CONVECTIVE POTENTIAL WITH UPPER LEVEL SUPPORT AND
CYCLOGENESIS/FRONTOGENESIS. A SLIGHT RISK AREA COULD EVENTUALLY BE
NEEDED ONCE MORE OF THE MESOSCALE DETAILS COME INTO BETTER FOCUS,
ALBEIT TEMPERED BY PROGRESSION. THERE WILL ALSO BE A SEPARATE AREA
OF ENHANCED RAINFALL NEAR THE CENTRAL GULF COAST AND EXTENDING
EASTWARD TO PORTIONS OF FLORIDA IN THE DAY 4/5 EROS. EVEN THOUGH
THE MAIN CIRCULATION FROM TROPICAL STORM SARA SHOULD DISSIPATE WELL
TO THE SOUTH BASED ON THE LATEST NHC FORECASTS, LEAD MOISTURE WILL
ADVECT NORTHWARD AHEAD OF THE APPROACHING AND WAVY COLD FRONT.
ACCORDINGLY, MARGINAL RISK ERO AREAS WERE ISSUED AND A SLIGHT RISK
AREA HAS BEEN INTRODUCED GIVEN GROWING THREAT BY DAY 5/TUESDAY.
SOME STRONG TO SEVERE THUNDERSTORMS ARE LIKELY TO DEVELOP IN THE
WARM SECTOR OF THE PLAINS LOW PRESSURE SYSTEM INTO MONDAY, MAINLY
ACROSS PORTIONS OF NORTH TEXAS AND INTO CENTRAL OKLAHOMA, WHERE THE
MOST FAVORABLE WIND SHEAR AND INSTABILITY PARAMETERS ARE LIKELY TO
BE IN PLACE. THIS IS SOMETHING THAT THE STORM PREDICTION CENTER IS
MONITORING CLOSELY IN THE DAYS AHEAD. THERE MAY ALSO BE SOME SNOW
ON THE NORTHWESTERN EDGE OF THE PRECIPITATION SHIELD ACROSS
PORTIONS OF THE DAKOTAS AS THE SURFACE LOW OCCLUDES AND A
DEFORMATION ZONE LIKELY DEVELOPS.
TEMPERATURES ARE EXPECTED TO BE QUITE CHILLY ACROSS THE ROCKIES AND
ADJACENT PORTIONS OF THE INTERMOUNTAIN WEST AND THEN PLAINS IN THE
WAKE OF COLD FRONTAL PASSAGES, WITH A STRONG SURFACE HIGH BUILDING
IN. SOME OVERNIGHT LOWS COULD BE NEAR OR EVEN BELOW ZERO FOR
PORTIONS OF THE CENTRAL AND NORTHERN ROCKIES. MEANWHILE, WARM AND
HUMID PRE-FRONTAL CONDITIONS ARE LIKELY FOR THE GULF COAST AND TO
THE SOUTHEAST U.S. WITH DEEP SOUTHERLY FLOW FROM THE TROPICS
THROUGH MIDWEEK. PRE-FRONTAL WARMTH FARTHER INLAND ACROSS THE
EAST-CENTRAL U.S. AND EAST/NORTHEAST WILL BE FOLLOWED BY A RETURN
TO MUCH COOLER FALL-LIKE CONDITIONS TO CLOSE OUT THE WORK WEEK.
HAMRICK/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 (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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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