038
FXUS02 KWBC 082106
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
406 PM EST TUE NOV 08 2022
VALID 12Z FRI NOV 11 2022 - 12Z TUE NOV 15 2022
...HEAVY RAINS FROM NICOLE WILL CONTINUE TO SPREAD INLAND ACROSS
THE APPALACHIANS FRIDAY AND ACROSS THE NORTHEAST FRIDAY NIGHT INTO
SATURDAY...
..OVERVIEW
A LOW EJECTING NORTHEAST OUT OF THE SOUTHWEST THROUGH MIDWEEK IS
FORECAST DEVELOP INTO A MEAN LONG WAVE TROUGH OVER CENTRAL AND
EASTERN STATES WITH AN UPPER LOW DEVELOPING AND LINGERING THIS
WEEKEND OVER THE GREAT LAKES. NICOLE WILL EJECT NORTH AHEAD OF
THIS TROUGH, CURRENTLY ON AN INTERIOR EAST COAST TRACK AS IT
BECOMES POST-TROPICAL FRIDAY NIGHT/SATURDAY. HEAVY RAIN ALONG AND
WELL EAST OF THE TRACK IS FORECAST FOR THE APPALACHIANS/UPPER OHIO
VALLEY AND ACROSS THE NORTHEAST FRIDAY NIGHT INTO SATURDAY. AN
AMPLIFYING UPPER RIDGE OVER THE NORTHEAST PACIFIC/NORTHWESTERN
NORTH AMERICA WILL HELP PROMOTE THE CENTRAL/EASTERN TROUGHING AND
BELOW NORMAL TEMPERATURES OVER MUCH OF THE COUNTRY INTO NEXT WEEK.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
THE 00Z/12Z CONSENSUS IS FOR A LESS POTENT LOW/MORE OF A SHARP
TROUGH OVER THE NORTHERN PLAINS FRIDAY THAN THEN STILL DEVELOPS
INTO A DEEP UPPER LOW/LARGE EASTERN TROUGH THIS WEEKEND WITH AN
UPPER RIDGE BUILDING UP THE WEST COAST UP TO THE YUKON/ALASKA AREA
INTO NEXT WEEK WHICH MAINTAINS THE CENTRAL/EASTERN TROUGHING. THE
GFS HAS BEEN STRONGEST WITH THE FRIDAY LOW OVER THE NORTHERN
PLAINS, BUT SINCE 00Z THE ECM AND CMC HAVE BEEN WEAKER WITH NOW
THE 12Z GFS/UKMET ON BOARD WITH THAT PROGRESSION. IN ORDER TO
MAINTAIN SOME CONTINUITY WITH THE PREVIOUS FORECAST, THE 06Z GFS
WAS FAVORED IN THE BLEND THROUGH DAY 5 BEFORE FOCUSING MORE ON
INPUT FROM ENSEMBLE MEANS, BUT THE 12Z GFS HAS COME IN MORE IN
LINE WITH THE 00Z/12Z CONSENSUS, SO CONTINUED MOVEMENT TO A
STRONGER RIDGE/TROUGH PATTERN FROM THE GENERAL CONSENSUS IS
ANTICIPATED.
EAST OF THE DEVELOPING TROUGH/LOW, GUIDANCE CONTINUES TREND WEST
AND SOMEWHAT FASTER AS IT GETS SWEPT UP BY THE TROUGH FROM THE
PLAINS, WITH SOME SPREAD STILL AMONG THE LATEST GUIDANCE. THE WPC
QPF FOR DAY 4 WAS GENERALLY A BLEND OF THE NBM WITH THE 06Z GFS
AND 00Z ECMWF THAT WAS THEN UPDATED FOR THE FARTHER WEST SHIFT
FROM THE 12Z GFS.
GENERAL AGREEMENT IS WITH A FAIRLY QUIET STRETCH PRECIP-WISE AFTER
THE REMNANTS OF NICOLE LIFT NORTH THOUGH LAKE EFFECT SNOW IS
EXPECTED ACROSS TYPICAL SNOW LEVELS OFF THE GREAT LAKES INTO NEXT
WEEK AND SHORTWAVE IMPULSES RIDING THE RIDGE WILL RESULT IN
LOCALIZED PRECIP FOR THE CENTRAL/POTENTIALLY SOUTHEAST PARTS OF
THE COUNTRY. THERE IS ALSO GENERAL AGREEMENT ON THE MEAN RIDGE
BUILDING/LIFTING FARTHER NORTH WITH POTENTIAL FOR A TROUGH/LOW
GETTING IN UNDER THE RIDGE OFF THE SOUTHERN CA COAST EARLY NEXT
WEEK. HOWEVER, TIMING/PLACEMENT/STRENGTH SHORTWAVE TROUGHS/LOWS
APPROACHING THE WEST COAST THIS WEEKEND IS NOTED AMONG THE MOST
RECENT CONSENSUS. BLENDING IN SOME GEFS/ECENS INTO THE FORECAST
DID BRING SOME PRECIP TO CA THIS WEEKEND AND PORTIONS OF THE WEST
EARLY NEXT WEEK.
..WEATHER/HAZARD HIGHLIGHTS
A MORE PROGRESSIVE/LESS CLOSED LOW REDUCES THE THREAT FOR
LINGERING SNOW BANDS WEST OF LAKE SUPERIOR FRIDAY NIGHT. UNDER THE
UPPER LOW WILL BE A LAKE EFFECT SNOW THREAT FOR TYPICAL SNOW BELTS
INTO NEXT WEEK.
THE GREATEST THREAT NOW FOR THE MEDIUM RANGE PERIOD WILL BE NICOLE
AS IT TRACKS QUICKLY INLAND FROM THE EAST COAST FRIDAY NIGHT INTO
SATURDAY. MOISTURE AHEAD OF NICOLE WILL SPREAD INLAND ACROSS THE
APPALACHIANS AND THE APPROACHING COLD FRONT FROM THE DEVELOPING
GREAT LAKES LOW WILL HELP TO ENHANCE RAINFALL. THERE IS A THREAT
FOR A PREDECESSOR RAINFALL EVENT SOMEWHERE IN THE NORTHEAST EVEN
WITH THE QUICKER GUIDANCE. GIVEN THE FARTHER INLAND TREND IN QPF
GUIDANCE, THE SLIGHT RISK IN THE DAY 4 EXPERIMENTAL ERO WAS NUDGED
WEST AND NORTH, AWAY FROM MUCH OF THE MID-ATLANTIC COAST, BUT
STILL FOR THE I-95 CORRIDOR NORTH FROM RICHMOND AND WEST TO THE
UPPER OHIO RIVER AND TO THE SHORE OF LAKE ONTARIO. GIVEN THE
COMBINATION OF TROPICAL MOISTURE AND FRONTAL CONVERGENCE, EMBEDDED
MODERATE RISKS MAY BE NECESSARY FOR THE HIGH RAINFALL RATES THAT
ARE POSSIBLE DESPITE MUCH OF THE AREA BEING RATHER DRY OVER THE
PAST WEEK.
BELOW NORMAL TEMPERATURES SPREAD ACROSS THE COUNTRY THROUGH EARLY
NEXT WEEK UNDER THE DEVELOPING TROUGH AND OFFSHORE RIDGE AXIS OUT
WEST. THE COLDEST AIR WILL SPREAD FROM THE NORTHERN ROCKIES AND
ACROSS THE NORTHERN GREAT PLAINS FRIDAY AND LINGER INTO NEXT WEEK.
MIN TEMP ANOMALIES OF 15 TO 25 DEGREES BELOW NORMAL ARE FORECAST
WITH SEVERAL DAYS OF SUBZERO MINS IN PORTIONS OF THE DAKOTAS,
EASTERN MONTANA AND NORTHERN MINNESOTA. MIN TEMP ANOMALIES OF 10
TO 15 DEGREES BELOW NORMAL WILL PERSIST OVER THE NORTHERN
ROCKIES/GREAT BASIN AND SPREAD DOWN THE MISSISSIPPI VALLEY THROUGH
THE SOUTHEAST SUNDAY THROUGH EARLY NEXT WEEK. MUCH ABOVE NORMAL
TEMPERATURES RETURNING TO THE EAST COAST AHEAD OF NICOLE WILL
BECOME SLIGHTLY BELOW NORMAL BY EARLY NEXT WEEK.
JACKSON
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
HAZARDS:
- HEAVY RAIN ACROSS PORTIONS OF THE NORTHEAST, THE
CENTRAL/SOUTHERN APPALACHIANS, THE MID-ATLANTIC,
THE SOUTHEAST, THE LOWER GREAT LAKES, AND THE OHIO VALLEY, FRI,
NOV 11.
- FLOODING POSSIBLE ACROSS PORTIONS OF THE SOUTHEAST.
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE SOUTHEAST.
- HIGH WINDS ACROSS PORTIONS OF THE SOUTHEAST, THE GREAT LAKES,
THE UPPER MISSISSIPPI VALLEY, AND
THE NORTHERN PLAINS, FRI, NOV 11.
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL
PLAINS AND THE NORTHERN PLAINS,
FRI-SAT, NOV 11-NOV 12.
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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