274
FXUS02 KWBC 091858
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
157 PM EST WED NOV 09 2022
VALID 12Z SAT NOV 12 2022 - 12Z WED NOV 16 2022
...HEAVY RAINS FROM NICOLE MAY CONTINUE ACROSS PARTS OF THE
NORTHEAST INTO SATURDAY...
..OVERVIEW
WHAT IS LEFT OF NICOLE BY THE START OF THE MEDIUM RANGE PERIOD
SHOULD GET PICKED UP BY AN AMPLIFIED UPPER TROUGH MOVING IN FROM
THE MIDWEST. THIS SHOULD HELP TO LIFT THE HEAVY RAINFALL FROM
NICOLE AWAY FROM THE CONUS BY SATURDAY, ASIDE FROM PERHAPS SOME
LINGERING HEAVY RAIN OVER THE NORTHEAST. OTHERWISE THE LARGE SCALE
PATTERN WILL FEATURE AN AMPLIFYING UPPER RIDGE OVER THE NORTHEAST
PACIFIC/NORTHWESTERN NORTH AMERICA, PROMOTING BROAD CYCLONIC FLOW
AND BELOW NORMAL TEMPERATURES OVER MUCH OF THE LOWER 48 THROUGH AT
LEAST THE MIDDLE OF NEXT WEEK. CONFIDENCE IN EMBEDDED DETAILS IS
STILL ON THE LOWER SIDE, WITH PARTICULAR FOCUS ON AN UPPER
SHORTWAVE/SURFACE SYSTEM THAT COULD SPREAD PRECIPITATION OF
VARYING TYPES OVER PARTS OF THE CENTRAL/EASTERN U.S. IN THE
EARLY-MID WEEK TIME FRAME.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
THE GUIDANCE STILL SHOWS GOOD AGREEMENT IN PRINCIPLE BUT LOCALLY
MEANINGFUL DETAIL DIFFERENCES FOR THE EVENTUAL ABSORPTION OF
NICOLE BY THE APPROACHING TROUGH/SURFACE FRONT BY THE START OF THE
MEDIUM RANGE PERIOD ON SATURDAY. BEHIND THE SUPPORTING TROUGH
CROSSING THE EAST, MODELS AND ENSEMBLES CONTINUE TO VARY FOR
INDIVIDUAL FEATURES WITHIN THE OVERALL CYCLONIC FLOW COVERING MUCH
OF THE THE LOWER 48 AND SOUTHERN CANADA. AT LEAST FOR THE MOMENT
THOUGH, MOST OF THE 00Z/06Z GUIDANCE DEVELOPED SOME DEGREE OF
CLUSTERING. CURRENTLY THE PRIMARY FEATURES OF NOTE SHOULD BE AN
UPPER LOW MOVING INTO OREGON/NEVADA AND SHORTWAVE DROPPING INTO
THE NORTHERN TIER DURING THE WEEKEND. BY MONDAY-WEDNESDAY UPSTREAM
FLOW MAY FEED INTO THE NORTHERN TROUGH AND SPLITTING PACIFIC
ENERGY MAY DROP INTO THE NORTHWEST, SINKING SOUTHWARD WITH TIME.
MEANWHILE THE MAJORITY CLUSTER SHOWS THE INITIAL WESTERN UPPER LOW
CROSSING THE SOUTHERN ROCKIES AROUND EARLY MONDAY AND THEN OPENING
UP AS IT ACCELERATES TO THE EAST-NORTHEAST. GFS RUNS HAVE BEEN
WAFFLING WITH RESPECT TO HOW MUCH PHASING MAY OCCUR BETWEEN THE
NORTHERN TIER TROUGH AND EJECTING SOUTHERN FEATURE, WITH 00Z/12Z
RUNS MORE AGGRESSIVE IN THAT REGARD (AND MORE INLAND AT THE
SURFACE) THAN THE 06Z RUN THAT COMPARED BETTER TO THE 00Z
ECMWF/CMC AS WELL AS THE ENSEMBLE MEANS (WITH EARLY DAY 7
WEDNESDAY SURFACE LOW PRESSURE NEAR THE EAST COAST). THIS MAJORITY
CLUSTER ALSO COMPARED REASONABLY WELL FOR THE ELONGATED TROUGH
FORECAST TO DROP THROUGH THE WEST NEXT WEEK. NOT SURPRISINGLY, NEW
12Z RUNS SHOW SOME SIGNIFICANT DIFFERENCES/CHANGES FOR BOTH THE
WESTERN ENERGY AND EVOLUTION OVER THE EASTERN HALF OF THE COUNTRY.
THIS INCLUDES THE ECMWF SHIFTING TO A MORE PHASED SOLUTION EAST OF
THE ROCKIES NEXT WEEK.
BASED ON THE 00Z/06Z ARRAY OF GUIDANCE, THE UPDATED FORECAST
EMPLOYED A BLEND OF THE 06Z GFS/00Z ECMWF AND LESSER INPUT OF THE
00Z CMC/UKMET THROUGH ABOUT THE FIRST HALF OF THE PERIOD AND THEN
INCORPORATED SOME OF THE 06Z GEFS/00Z ECMWF MEANS. THE REFINEMENT
OF SHORTWAVE DETAILS HAS YIELDED SOME NOTICEABLE CONTINUITY
CHANGES, INCLUDING BETTER DEFINITION OF WAVINESS ALONG THE
GULF/EAST COAST REGIONS LATE IN THE PERIOD (WHICH STILL HAS
POTENTIAL TO BE STRONGER AND MORE INLAND).
..WEATHER/HAZARD HIGHLIGHTS
HEAVY RAINFALL ACROSS THE NORTHEAST ASSOCIATED WITH NICOLE SHOULD
BE IN THE PROCESS OF LIFTING OUT DURING THE DAY SATURDAY. THE
TRAILING UPPER TROUGH CROSSING THE EAST ALONG WITH COOL LOW LEVEL
CYCLONIC FLOW WILL SUPPORT SOME LAKE EFFECT SNOW WITHIN THE
TYPICAL SNOW BELTS OVER THE UPPER AND LOWER GREAT LAKES, MAINLY
DURING THE WEEKEND AND EARLY NEXT WEEK. THE WEST MAY SEE SOME
LIGHT PRECIPITATION ACCOMPANYING THE UPPER LOW EXPECTED TO TRACK
FROM OREGON SOUTHEASTWARD THIS WEEKEND. LATEST CONSENSUS IS
MAINTAINING STRONGER DEFINITION OF THIS FEATURE AS IT OPENS AND
CONTINUES EAST-NORTHEAST FROM THE SOUTHERN ROCKIES EARLY-MID WEEK,
LEADING TO MORE SURFACE WAVINESS FROM THE GULF COAST TO EAST
COAST. THIS YIELDS BROADER COVERAGE OF PRECIPITATION FROM THE
SOUTHERN HALF OF THE PLAINS THROUGH THE EAST. RAIN COULD BE
LOCALLY HEAVY ALONG THE GULF COAST AND IT WILL BE POSSIBLE FOR
SOME WINTRY PRECIPITATION TO EXIST IN THE NORTHERN FRINGE OF THE
MOISTURE SHIELD. IT WILL TAKE ADDITIONAL TIME TO RESOLVE IMPORTANT
SYSTEM DETAILS THAT WILL DETERMINE THE COVERAGE/INTENSITY/TYPE OF
PRECIPITATION.
BELOW NORMAL TEMPERATURES ALREADY IN PLACE TO THE WEST OF THE
MISSISSIPPI RIVER AS OF EARLY SATURDAY WILL EXTEND THROUGH THE
EAST DURING THE WEEKEND. BROAD UPPER TROUGHING IN RESPONSE TO THE
STRONG RIDGE OFFSHORE THE WEST COAST SHOULD KEEP THE COLD PATTERN
IN PLACE THROUGH MIDWEEK, AND LIKELY BEYOND PER THE CLIMATE
PREDICTION CENTER WEEK 2 FORECAST. THE COLDEST AIR SHOULD BE OVER
PARTS OF MONTANA AND THE DAKOTAS SATURDAY-MONDAY WITH SOME
READINGS AT LEAST 20-30F BELOW NORMAL, INCLUDING LOCALLY SUBZERO
MORNING LOWS. SOME OF THE COLD AIR WILL PUSH INTO THE
CENTRAL/SOUTHERN PLAINS BY MONDAY-WEDNESDAY, BRINGING HIGHS DOWN
TO 15-20F OR SO BELOW NORMAL. COLDEST ANOMALIES OVER THE WEST
SHOULD TEND TO BE OVER THE GREAT BASIN WITH MULTIPLE DAYS OF HIGHS
10-25F BELOW NORMAL. ABOVE NORMAL TEMPERATURES ALONG THE IMMEDIATE
EAST COAST ON SATURDAY SHOULD QUICKLY GIVE WAY TO HIGHS 5-15F
BELOW NORMAL OVER MUCH OF THE EAST THEREAFTER. MAINE AND FLORIDA
COULD BE EXCEPTIONS WITH NEAR TO SLIGHTLY ABOVE NORMAL
TEMPERATURES.
RAUSCH/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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