072
FXUS02 KWBC 142028
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
327 PM EST MON NOV 14 2022
VALID 12Z THU NOV 17 2022 - 12Z MON NOV 21 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 RATHER COLD PATTERN IS EXPECTED TO BE IN PLACE ACROSS MUCH OF
THE NATION FOR THE END OF THE WEEK INTO NEXT WEEKEND WITH BROAD
CYCLONIC FLOW ALOFT AROUND A DEEP UPPER LEVEL TROUGH CENTERED NEAR
THE NORTH-CENTRAL U.S. AND EXTENDING TO HUDSON BAY. DURING THIS
PERIOD, MULTIPLE COLD FRONTS WILL SWEEP THROUGH THE NATION WHICH
WILL REINFORCE THE CHILLY AIRMASS. ADDITIONALLY, A STRONG UPPER
RIDGE AXIS SHOULD PREVAIL JUST OFF THE WEST COAST THROUGH SATURDAY
BEFORE SOMEWHAT WEAKENING. A WELL ORGANIZED STORM SYSTEM WILL BE
CROSSING SOUTHEAST CANADA ON THURSDAY, WITH COASTAL RAIN AND
INLAND SNOW EXPECTED, FOLLOWED BY LAKE EFFECT SNOW DOWNWIND OF THE
GREAT LAKES.
..GUIDANCE AND PREDICTABILITY ASSESSMENT
THE 06/12Z GUIDANCE OVERALL HAS A GOOD HANDLE ON THE LARGE SCALE
PATTERN INTO THE WEEKEND THAT SHOWS A
STRONG REINFORCEMENT OF THE ARCTIC AIR MASS ACROSS MUCH OF THE
NORTHERN TIER STATES. THE GLOBAL GUIDANCE AND THE ENSEMBLE MEANS
ARE FAIRLY CLUSTERED FOR THE GREAT LAKES REGION, AT LEAST THROUGH
THE MIDDLE OF THE EXTENDED. THERE IS STILL A SIGNAL FOR A STORM TO
DEVELOP NEAR THE SOUTHEAST COAST WHICH IS DEPICTED AS A WEAKER
SYSTEM AT THIS TIME. THIS EQUATES TO A LOWER POTENTIAL FOR
PRECIPITATION TO ADVANCE MUCH INLAND.
THE WPC FORECAST WAS PRIMARILY BASED ON A MULTI-DETERMINISTIC
MODEL BLEND THROUGH INTO THE WEEKEND WITH INCREASING THE INCLUSION
AND WEIGHTING OF THE GEFS AND EC ENSEMBLE MEANS TO ACCOUNT FOR THE
GREATER MODEL DIFFERENCES FOR THE WEEKEND AND BEYOND. FOR THE QPF
FORECAST, PARTICULARLY FOR AND 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 TOWARD THE CMC, ECWMF, AND
ENSEMBLE MEANS TO INCREASE VALUES.
..WEATHER/HAZARD HIGHLIGHTS
A VAST AREA COVERING THE NORTHERN AND CENTRAL STATES WILL HAVE
BELOW SEASONAL AVERAGE TEMPERATURES FOR MID-NOVEMBER THROUGH MOST
OF THE EXTENDED PERIOD.
SOME LOCATIONS ACROSS THE NORTHERN HIGH PLAINS ARE FORECAST TO
HAVE DAILY HIGHS ONLY CLIMBING INTO IN THE LOW TEENS WITH
OVERNIGHT LOWS DIPPING BELOW ZERO. SOME RECORD LOW TEMPERATURES
ARE POSSIBLE ACROSS WESTERN REACHES OF THE 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. CHILLY TEMPERATURES WILL REACH THE GULF COAST AND EVEN
MUCH OF THE FLORIDA PENINSULA FOR AT LEAST THE FIRST HALF OF THE
FORECAST PERIOD, WITH HIGHS GENERALLY RUNNING 10-20 DEGREES BELOW
MID-NOVEMBER AVERAGE. BY EARLY NEXT WEEK THERE MAY BE SOME WARMING
BACK TO NEAR SEASONAL TEMPERATURES.
MOST OF THE COUNTRY WILL BE RELATIVELY DRY PRECIPITATION-WISE
GIVEN THE PATTERN. LAKE EFFECT SNOW WILL LIKELY PERSIST DOWNWIND
OF THE GREAT LAKES OWING TO STRONG COLD AIR ADVECTION OVER THE
WARMER WATERS, WITH THE HEAVIEST SNOW EXPECTED EAST OF LAKE ERIE
AND LAKE ONTARIO. SOME SNOW SHOWERS ARE ALSO LIKELY ACROSS
PORTIONS OF THE ROCKIES AS A WEAK DISTURBANCE DROPS SOUTHEASTWARD,
BUT NOTHING MAJOR EXPECTED THERE. THERE IS A BIT MORE UNCERTAINTY
REGARDING THE POTENTIAL EVOLUTION AND TRACK OF A WAVE OF LOW
PRESSURE OVER THE GULF THAT COULD BRING LIGHT TO MODERATE RAIN FOR
THE GULF COAST REGION AND THE INTERIOR SOUTHEAST BY THE WEEKEND,
SO THIS WILL CONTINUE TO BE CLOSELY MONITORED.
CAMPBELL
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:
- FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE SOUTHEAST.
- FLOODING LIKELY ACROSS PORTIONS OF THE SOUTHEAST.
- MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE NORTHERN
PLAINS/ROCKIES, THE UPPER
MISSISSIPPI VALLEY, AND THE GREAT LAKES, THU-MON, NOV 17-NOV 21.
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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