132
FXUS02 KWBC 120704
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
204 AM EST MON JAN 12 2026
VALID 12Z THU JAN 15 2026 - 12Z MON JAN 19 2026
... A COMPLEX/BROAD COASTAL LOW IS EXPECTED TO BRING A WINTRY MIX
FOLLOWED BY ACCUMULATING SNOW TO PORTIONS OF THE APPALACHIANS,
MID-ATLANTIC, AND NEW ENGLAND THURSDAY/FRIDAY...
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST MODEL GUIDANCE RUNS CONTINUE TO SHOW REASONABLY GOOD
AGREEMENT ON THE HIGHLY AMPLIFIED UPPER FLOW PATTERN THROUGH NEXT
WEEK WITH RIDGING NEAR THE WEST COAST AND BROAD TROUGHING
NEAR AND EAST OF THE ROCKIES. DETAILS ARE A PROBLEM NEAR THE EAST
COAST EARLY ON, AS THE GUIDANCE CAN'T FIGURE OUT THE INTERACTION/
SPACING BETWEEN A COLD LOW IN QUEBEC AND A SHORTWAVE/POSSIBLE UPPER
LOW MOVING OUT OF THE APPALACHIANS. LUCKILY, THE SYSTEM'S KICKER
SHORTWAVE MOVING TOWARDS MN HAS BEEN BEHAVED.
WPC'S MEDIUM RANGE 500 HPA HEIGHTS/PRESSURES/FRONTS PROGS WERE
CREATED FROM A COMPROMISE OF THE DETERMINISTIC GUIDANCE EARLY,
WHICH THEN SAW SOME INCORPORATION OF THE 11/12Z ECMWF ENSEMBLE MEAN
AND 00Z NAEFS MEAN. THIS OVERALL PLAN SEEMS TO PROVIDE A GOOD
FORECAST STARTING POINT AND SEEMS CONSISTENT WITH THE 01Z NBM DESPITE
CONTINUED UNCERTAINTIES WITH SMALLER SCALE EMBEDDED SYSTEM
VARIANCES.
..WEATHER/HAZARDS HIGHLIGHTS
OVERALL, THIS PATTERN IS NOT A WET ONE FOR THE LOWER 48 SHOWING
GENERALLY OFFSHORE OR DOWNSLOPE FLOW OFF THE ROCKIES, SO WE
CONTINUE THE MULTI-DAY TREND OF NO EXCESSIVE RAINFALL AREAS FOR
DAYS 4-5/THURSDAY AND FRIDAY.
SHORTWAVES ALOFT/CLIPPER SYSTEMS MOVING WITHIN AND THROUGH THE
BROAD TROUGHING OVER THE PLAINS, GREAT LAKES, AND EAST ARE EXPECTED
TO BRING SKIRMISHES OF LAKE EFFECT/ENHANCED SNOW NEAR THE GREAT
LAKES AS WELL AS PORTIONS OF THE NORTHERN PLAINS, MIDWEST, AND
APPALACHIANS/NORTHEAST. THE GUIDANCE KEEPS CHANGING ITS TUNE
REGARDING DETAILS WITHIN THE BROAD CYCLONE NEAR THE NORTHEAST
THURSDAY/FRIDAY. AT THIS TIME, IT APPEARS THAT THE SYSTEM WILL
BRING AN INITIALLY WINTRY MIX WHICH TRANSITIONS TO SNOW FOR
PORTIONS OF THE MID- ATLANTIC STATES AND NEW ENGLAND, THOUGH THE
DEGREE OF SNOW ACCUMULATION WILL LIKELY BE DEPENDENT ON THE DEPTH
OF THE UPPER LEVEL SHORTWAVE/LOW. THE FLOW PATTERN IN WHICH THE
NORTHEAST SYSTEM IS EMBEDDED IS ONE OF GREATER FORECAST UNCERTAINTY
SINCE IT IS AN UNUSUAL CASE OF TRINARY INTERACTION, AND ANY SMALL
CHANGE IN ANY OF THE TWO STEERING SYSTEMS (COLD LOW IN QUEBEC AND
KICKER SHORTWAVE MOVING TOWARDS MN) COULD HAVE SIGNIFICANT IMPACT
ON THE COASTAL LOW TRACK/STRENGTH. PORTIONS OF THE GULF COAST LATE
SHOULD SEE SUFFICIENT MOISTURE INTRUSION FOR RAIN.
TEMPERATURES WILL BE ABOVE AVERAGE ACROSS THE WEST AND HIGH PLAINS
AND BELOW AVERAGE FOR PORTIONS OF THE EAST FROM FRIDAY ONWARD.
THERE IS ALSO SOME INDICATION FOR ENHANCED WIND POTENTIAL FOR
SOUTHERN CALIFORNIA AND VICINITY TO MONITOR GIVEN PRESSURE
GRADIENTS AND OFFSHORE FLOW.
ROTH/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 FORECAST (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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