436
FXUS02 KWBC 150700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM EST TUE NOV 15 2022
VALID 12Z FRI NOV 18 2022 - 12Z TUE NOV 22 2022
***A VAST PORTION OF THE LOWER 48 WILL HAVE DAILY TEMPERATURES
THAT RESEMBLE THOSE OF JANUARY RATHER THAN MID-NOVEMBER WITH
WIDESPREAD SUBFREEZING MAXIMUM TEMPERATURES EXPECTED ACROSS THE
NORTH-CENTRAL STATES ALONG WITH LAKE EFFECT SNOW***
..SYNOPTIC OVERVIEW
A HIGHLY AMPLIFIED UPPER LEVEL FLOW PATTERN WILL BE IN PLACE
ACROSS THE COUNTRY FOR THE END OF THE WORK WEEK WITH A DEEP TROUGH
EXTENDING FROM HUDSON BAY TO THE MIDWEST STATES. AN ARCTIC FRONT
IS PROGGED TO REINFORCE THE ALREADY VERY COLD AIRMASS THAT WILL BE
IN PLACE ACROSS THE NORTH-CENTRAL U.S. THAT IS FORECAST TO REACH
THE EAST COAST IN TIME FOR THE WEEKEND. THIS TROUGH AND
ACCOMPANYING JANUARY-LIKE TEMPERATURES WILL LIKELY HAVE SOME
STAYING POWER UNTIL EARLY NEXT WEEK, WHEN THERE ARE SIGNS OF A
PATTERN CHANGE EMERGING. THE DEEP TROUGH WILL LIKELY BEGIN
LIFTING OUT AS A MORE ZONAL FLOW PATTERN COMMENCES ACROSS MUCH OF
THE COUNTRY. OUT WEST, A PACIFIC STORM SYSTEM WILL LIKELY MOVE
INLAND AS THE UPPER RIDGE AXIS DECAYS BY SUNDAY AND INTO MONDAY.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
THE 00Z DETERMINISTIC GUIDANCE NOW HAS AN EXCELLENT SYNOPTIC SCALE
DEPICTION OF THE BROAD UPPER TROUGH OVER THE CENTRAL-EASTERN U.S.
FOR FRIDAY AND INTO THE WEEKEND WITH ABOVE AVERAGE CONFIDENCE AT
THIS TIME FRAME. THE MODELS ALSO AGREE WELL ON SAID TROUGH
LIFTING OUT STARTING MONDAY AND HERALDING A PATTERN CHANGE. THE
GREATEST MODELS DIFFERENCES ARE APPARENT ACROSS THE WESTERN U.S.
GOING INTO EARLY NEXT WEEK AS A PACIFIC SHORTWAVE APPROACHES THE
CENTRAL-NORTHERN WEST COAST REGION. THE CMC IS CONSIDERABLY
WEAKER THAN THE GFS/ECMWF FOR THE SYSTEM REACHING THE COAST
MONDAY, ALTHOUGH THE CMC SHOWS A STRONGER SHORTWAVE FOLLOWING
BEHIND IT THAT IS NOT REFLECTED MUCH IN THE OTHER GUIDANCE.
THE WPC FORECAST WAS PRIMARILY BASED ON A MULTI-DETERMINISTIC
MODEL BLEND THROUGH THE WEEKEND, WITH A GRADUAL INCREASE IN USE OF
THE EC AND GEFS MEANS GOING INTO NEXT MONDAY AND TUESDAY. FOR THE
QPF FORECAST, PARTICULARLY IN THE VICINITY OF THE GREAT LAKES, THE
NBM 4.0 SOLUTION WAS TOO LIGHT GIVEN THE SETUP FOR THE LAKE
ENHANCED PRECIPITATION, SO TRENDED MORE TOWARD THE GFS AND ECWMF
TO INCREASE VALUES.
..WEATHER/HAZARD HIGHLIGHTS
WIDESPREAD WELL BELOW AVERAGE TEMPERATURES FOR THIS TIME OF YEAR
CAN BE EXPECTED ACROSS A MAJORITY OF THE COUNTRY TO CLOSE OUT THE
WORK WEEK AND GOING INTO THE WEEKEND, WITH THE MOST IMPRESSIVE
READINGS ACROSS MINNESOTA, NORTH DAKOTA AND MONTANA WHERE HIGHS
WILL ONLY REACH INTO THE 10S FRIDAY THROUGH SUNDAY, AND LOWS
WITHIN 5 DEGREES OF ZERO FOR MANY OF THOSE SAME AREAS. SOME
RECORD LOW TEMPERATURES ARE POSSIBLE ACROSS PORTIONS OF THE
WESTERN HIGH PLAINS, AND SOME RECORD LOW MAXIMUMS ARE ALSO
POSSIBLE ACROSS PORTIONS OF THE CENTRAL PLAINS TO THE UPPER
MIDWEST BEHIND THE NEXT SURGE OF ARCTIC AIR. IT WILL ALSO BE
QUITE CHILLY EXTENDING SOUTHWARD TO THE GULF COAST AND EVEN MUCH
OF THE FLORIDA PENINSULA FOR AT LEAST THE FIRST HALF OF THE
FORECAST PERIOD, WITH HIGHS GENERALLY RUNNING 5 TO 15 DEGREES
BELOW MID-NOVEMBER AVERAGES. LOOKING AHEAD TO EARLY NEXT WEEK,
THERE WILL LIKELY BE SOME ABATEMENT IN THE COLD WEATHER PATTERN AS
THE DEEP UPPER TROUGH BEGINS LIFTING OUT WITH A MORE ZONAL FLOW
EVOLVING.
IN TERMS OF PRECIPITATION, MUCH OF THE NATION SHOULD BE RELATIVELY
DRY AS A SPRAWLING SURFACE HIGH GOVERNS THE OVERALL WEATHER
PATTERN. LAKE EFFECT SNOW IS LIKELY TO BE PERSISTENT DOWNWIND OF
THE GREAT LAKES THROUGH SUNDAY OWING TO STRONG COLD AIR ADVECTION
OVER THE WARMER WATERS, WITH THE HEAVIEST SNOW EXPECTED EAST OF
LAKE ERIE AND LAKE ONTARIO WHERE OVER A FOOT OF ACCUMULATION IS
POSSIBLE. SHOWERS AND MOUNTAIN SNOW ARE LIKELY TO MAKE A RETURN
TO THE WEST COAST STATES EARLY NEXT WEEK AS THE PACIFIC STORM
SYSTEM MOVES INLAND.
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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