431
FXUS02 KWBC 231900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 PM EST MON JAN 23 2023
VALID 12Z THU JAN 26 2023 - 12Z MON JAN 30 2023
...STRONG STORM TO PROLONG A HEAVY SNOW AND HIGH WIND THREAT OVER
THE INTERIOR NORTHEAST INTO THURSDAY...
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
COMPOSITE BLEND OF WELL CLUSTERED AND CONSISTENT GUIDANCE FROM THE
06 UTC GFS, 00 UTC ECMWF/UKMET/CANADIAN, THE 13 UTC NATIONAL BLEND
OF MODELS (NBM) AND WPC CONTINUITY THURSDAY INTO SATURDAY IN AN
ACTIVE PATTERN WITH SEEMINGLY ABOVE NORMAL PREDICTABILITY. 12 UTC
GUIDANCE NOW ALSO REMAINS IN LINE WITH THIS FORECAST STRATEGY.
HOWEVER, THERE STILL ARE AMPLE CONCERNS BY THE WEEKEND WITH THE
DISPARATE MODEL HANDLING OF COMPLEX ALASKA/GULF OF ALASKA SYSTEM
ENERGIES SET TO DIG INTO THE WESTERN U.S. TO THE LEE OF AN
AMPLIFIED EASTERN PACIFIC UPPER RIDGE. RECENT GFS RUNS HAVE
OFFERED THE LEAST AMPLIFIED SOLUTION WHILE THE ECMWF/CANADIAN HAVE
BEEN THE MOST AMPLIFIED. PREFER AN ENSEMBLE MEAN SOLUTION TO
MITIGATE SOME OF THESE DIFFERENCES AND RUN TO RUN VARIATIONS. OF
THE ENSEMBLE SYSTEMS, PREFER THE ECMWF ENSEMBLE MEAN WHOSE MORE
AMPLIFIED UPPER TROUGH DEVELOPMENT THAN THE GEFS DOWN THROUGH THE
WEST COAST SEEMS TO FIT BEST WITH UPSTREAM UPPER RIDGE AMPLITUDE,
RECENT MODEL TRENDS, WPC CONTINUITY AND PATTERN HISTORY. THIS
SOLUTION IS ON THE MORE AMPLIFIED SIDE OF THE FULL ENVELOPE OF
SOLUTIONS, BUT NOT AS AMPLIFIED AS THE ECMWF/CANADIAN.
..WEATHER/HAZARD HIGHLIGHTS
THE LATEST IN A RECENT SERIES OF MAIN STORM SYSTEMS WILL REACH THE
NORTHEAST U.S. THURSDAY. ENHANCED SNOWS ARE ANTICIPATED TO LINGER
FROM THE LEE OF THE LOWER GREAT LAKES IN COOLED FLOW AS WELL AS
ACROSS INTERIOR AREAS OF THE WINDY NORTHEAST AS THE SECONDARY LOW
DEVELOPS, WITH GALES UP THE COAST WITH SECONDARY COASTAL LOW
DEVELOPMENT. THIS WILL BE IN RESPONSE TO AMPLIFIED TROUGH PASSAGE
ALOFT THAT EXITS THE REGION TO THE CANADIAN MARITIMES BY FRIDAY.
FOLLOWING THIS SYSTEM, AN ALBERTA CLIPPER LOW WILL WORK SOME SNOW
BACK INTO THE GREAT LAKES REGION FRIDAY. THE SOUTHWARD PLUNGE OF A
TRAILING COLD FRONT WILL MEANWHILE BEGIN TO DRIVE COLD CANADIAN
HIGH PRESSURE DOWN THROUGH THE NORTH-CENTRAL U.S. AND THEN INTO
THE WEST. EXPECT MUCH BELOW NORMAL TEMPERATURES ACROSS THE
NORTH-CENTRAL U.S. FOR THE WEEKEND INTO EARLY NEXT WEEK, WITH
HIGHS RUNNING UP TO 15-25 DEGREES BELOW NORMAL POTENTIALLY ACROSS
PORTIONS OF MONTANA, THE DAKOTAS, AND NEBRASKA. COLD AIR WILL ALSO
FILTER INTO THE NORTHWEST/INTERMOUNTAIN WEST. UPPER TROUGH
PASSAGE/HEIGHT FALLS WILL COMBINE WITH LOWER ATMOSPHERIC UPSLOPE
FETCH TO SPREAD A FOCUS FOR LOCALLY HEAVY TERRAIN ENHANCED SNOWS
DOWN ACROSS NORTH-CENTRAL PARTS OF THE INTERMOUNTAIN
WEST/ROCKIES/HIGH PLAINS.
ENERGIES DUG INTO THE WEST EJECT DOWNSTREAM TO POTENTIALLY SUPPORT
A NEW SYSTEM OR SYSTEMS THAT MAY ORGANIZE OVER THE WEEKEND INTO
EARLY NEXT WEEK OVER THE SOUTH. GULF MOISTURE RETURN MAY SUPPORT A
MODERATE TO HEAVY RAINFALL FOCUS OVER THE CENTRAL GULF COAST
STATES AND VICINITY, WITH MORE MODEST RAINS SPREADING NORTHWARD
OVER THE EAST-CENTRAL U.S. INTO/AHEAD OF A WAVY FRONT. IN THIS
PATTERN, THE PRE-FRONTAL AIRMASS WARMS AS UPPER RIDGING BUILDS
FROM THE SOUTHEAST. THERE IS A SIGNAL FOR PLOWABLE SNOWS ON THE
NORTHERN PERIPHERY OF THE EMERGING OVERALL PRECIPITATION SHIELD
MORE UNDER LEAD INFLUENCE FROM THE AFOREMENTIONED COLD CANADIAN
AIRMASS.
CAMPBELL/SCHICHTEL
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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