850
FXUS02 KWBC 080726
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 AM EST TUE NOV 08 2022
VALID 12Z FRI NOV 11 2022 - 12Z TUE NOV 15 2022
...NICOLE TO IMPACT FLORIDA AND THE EAST COAST THE SECOND HALF OF
THIS WEEK...
..OVERVIEW
A DEEP CLOSED UPPER LOW WILL BE IN PLACE ACROSS THE UPPER
MISSISSIPPI VALLEY BY THE START OF THE PERIOD ON FRIDAY. THIS
SYSTEM WILL BE RESPONSIBLE FOR A POTENTIALLY SIGNIFICANT WINTER
STORM AFFECTING PARTS OF THE NORTHERN PLAINS BUT SHOULD BE COMING
TO AN END LARGELY BY FRIDAY. MEANWHILE, WHAT IS NOW SUBTROPICAL
STORM NICOLE SHOULD BE STARTING TO GET PICKED UP AHEAD OF THE
APPROACHING PLAINS TROUGH BY FRIDAY, LIKELY SPREADING HEAVY RAIN
UP THE EASTERN SEABOARD THROUGH SATURDAY. A REBUILDING UPPER RIDGE
OVER THE NORTHEAST PACIFIC/NORTHWESTERN NORTH AMERICA WILL LIKELY
YIELD MEAN TROUGHING OVER MUCH OF CANADA INTO THE LOWER 48 BY THE
WEEKEND AND EARLY NEXT WEEK, ALONG WITH BELOW NORMAL TEMPERATURES
OVER MUCH OF THE COUNTRY.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
THERE IS GOOD AGREEMENT IN THE OVERALL UPPER PATTERN REGARDING THE
CLOSED LOW AND SURROUNDING TROUGHING PUSHING EAST, BUT DIFFERENCES
IN THE DETAILS PERTAINS TO MORE NOTICEABLE CONCERNS ON EXACT LOW
PLACEMENT BY EARLY FRIDAY ACROSS THE UPPER MIDWEST. THE CMC HAS
CONSISTENTLY BEEN WEAKER AND FASTER WITH THE SURFACE LOW THROUGH
THE UPPER MIDWEST LATE WEEK, AND WAS NOT PREFERRED IN TONIGHTS
BLEND. HOWEVER, SOME OF THE NEW 00Z GUIDANCE ALSO TRENDED TOWARDS
THE CMC. IT IS TOO EARLY TO TELL IF THIS IS A NEW TREND OR NOT,
BUT IT CERTAINLY WILL NEED TO BE MONITORED.
AHEAD OF THIS SYSTEM, GUIDANCE CONTINUES TO SHOW A LOT OF
UNCERTAINTY AS NICOLE ENTERS THE MEDIUM RANGE PERIOD (LIKELY WITH
A MORE TROPICAL CHARACTER BY THIS POINT), WITH A NOTABLE TREND
WEST AND SOMEWHAT FASTER COMPARED TO PRIOR RUNS (AND ESPECIALLY
WITH THE NEW 00Z GUIDANCE NOT AVAILABLE AT THE TIME OF FORECAST
GENERATION). THERE IS GOOD AGREEMENT THIS SYSTEM WILL GET SWEPT UP
BY THE TROUGH FROM THE PLAINS, BUT A LOT OF UNCERTAINTY STILL ON
TIMING. MUCH OF THE GUIDANCE IS SUGGESTING A QUICKER TRANSITION UP
THE EAST COAST, AND THE PREVIOUSLY MUCH SLOWER 18Z/NOV 7TH GFS HAS
TRENDED FASTER WITH ITS 00Z RUN AND CLOSER TO THE CONSENSUS. THE
WPC QPF FOR FRIDAY STUCK PRETTY CLOSE TO THE NBM CONSISTENT WITH
THE LATEST 03Z ADVISORY POINTS FROM NHC.
OUT WEST, MODELS AND ENSEMBLE MEMBERS CONTINUE TO BE ALL OVER THE
PLACE FOR EXACTLY HOW INITIAL EASTERN PACIFIC SHORTWAVE ENERGY MAY
SPLIT TO PRODUCE ONE OR MORE PACIFIC UPPER LOWS/SHORTWAVES (WHICH
MAY OR MAY NOT REACH THE WEST COAST), WITH THE REST OF THE ENERGY
ROUNDING A LARGER SCALE MEAN RIDGE AND DROPPING INTO SOUTHERN
CANADA AND THE LOWER 48. THERE MAY ALSO BE A SOUTHERN STREAM THAT
CARRIES SHORTWAVE ENERGY ACROSS THE EASTERN PACIFIC AND FAR
SOUTHERN TIER U.S.. CONFIDENCE IS VERY LOW IN THE DETAILS OUT WEST
BEYOND AS EARLY AS DAY 4. GIVEN THESE UNCERTAINTIES, THE WPC
FORECAST TRENDED VERY QUICKLY TOWARDS THE ENSEMBLE MEANS THE
SECOND HALF OF THE PERIOD TO HELP MITIGATE THE DIFFERENCES.
..WEATHER/HAZARD HIGHLIGHTS
THE SIGNIFICANT SNOWSTORM LIKELY TO ACCOMPANY THE DEEPENING
SURFACE LOW INTO THE UPPER MIDWEST WILL LARGELY BE COMING TO AN
END BY EARLY FRIDAY. THE EXCEPTION TO THIS COULD BE SOME LINGERING
MODEST ACCUMULATIONS ACROSS NORTHERN MINNESOTA AND THE UPPER
PENINSULA OF MICHIGAN ON FRIDAY INTO EARLY SATURDAY.
THE GREATEST THREAT NOW FOR THE MEDIUM RANGE PERIOD WILL BE NICOLE
AS IT TRACKS QUICKLY UP THE EAST COAST THROUGH SATURDAY. COASTAL
AND MARITIME IMPACTS THAT INCLUDE COASTAL FLOODING, TROPICAL STORM
FORCE WINDS, HEAVY RAINFALL, ROUGH SURF, AND BEACH EROSION ARE
POSSIBLE ASSOCIATED WITH NICOLE NEAR/OVER FLORIDA AND THE
SOUTHEAST. MOISTURE FROM THIS SYSTEM SHOULD MOVE UP MUCH OF THE
EAST COAST INTO THE WEEKEND THOUGH WITH MORE UNCERTAINTY IN THE
AMOUNTS AND COVERAGE. AN APPROACHING COLD FRONT WILL LIKELY HELP
TO PROVIDE SOME FOCUSED ENHANCEMENT OF RAINFALL AS WELL. GIVEN
TRENDS IN THE GUIDANCE, THE DAY 4 EXPERIMENTAL ERO MADE A
SIGNIFICANT CHANGE FROM WHAT WAS YESTERDAYS DAY 5, WITH A LARGE
SLIGHT RISK NOW INTO MUCH OF THE MID-ATLANTIC AND NORTHEAST. NOTE
THAT THIS AREA, ESPECIALLY THE EASTERN/WESTERN FRINGES, REMAINS
HIGHLY UNCERTAIN STILL AND THESE AREAS MAY HAVE TO SHIFT OR BE
UPGRADED IN FUTURE FORECASTS DEPENDING ON RAINFALL AMOUNTS AND THE
TRACK OF THE TROPICAL SYSTEM.
EXPECT MUCH OF THE WEST/ROCKIES INTO THE NORTHERN PLAINS TO SEE
BELOW NORMAL TEMPERATURES THROUGH THE FIRST PART OF NEXT WEEK. THE
COLDEST AIR WILL LIKELY BE ACROSS THE NORTHERN HIGH PLAINS AND
PLAINS FRIDAY-SUNDAY WITH HIGHS IN THAT AREA UP TO 20-30F BELOW
NORMAL. SOME LOCATIONS IN THE GREAT BASIN MAY SEE SIMILAR
ANOMALIES MAINLY ON FRIDAY. IN CONTRAST, WELL ABOVE NORMAL
TEMPERATURES WILL BE IN PLACE ALONG THE EAST COAST FRIDAY ALTHOUGH
A STRONG COLD FRONT CROSSING THROUGH THIS REGION LATE THIS WEEK
WILL USHER IN A MUCH COLDER AIRMASS THIS WEEKEND. HIGH
TEMPERATURES FROM THE MIDWEST TO PARTS OF THE INTERIOR
MID-ATLANTIC COULD BE AS MUCH AS 10 TO 20 DEGREES BELOW NORMAL.
THE COOLER TEMPERATURES WILL ALSO REACH THE EAST COAST THIS
WEEKEND, AND SUNDAY-TUESDAY LOOK TO BE NEAR OR BELOW NORMAL FOR
ALMOST THE ENTIRE CONUS.
SANTORELLI
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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