216
FXUS02 KWBC 171930
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 PM EST SAT JAN 17 2026
VALID 12Z TUE JAN 20 2026 - 12Z SAT JAN 24 2026
...DEEP TROUGHING WILL CAUSE CHILLY BELOW AVERAGE TEMPERATURES IN
THE EASTERN AND NORTHERN U.S. AND LAKE EFFECT SNOW...
..OVERVIEW
IT REMAINS THE CASE THAT A VERY AMPLIFIED PATTERN ALOFT WILL BE IN
PLACE AS THE PERIOD BEGINS TUESDAY, WITH RIDGING OVER THE WEST
COAST AND DEEP TROUGHING OVER THE CENTRAL AND EASTERN U.S., WITH
THE LATTER CAUSING BELOW TO MUCH BELOW AVERAGE TEMPERATURES. THIS
PATTERN WILL ALSO BE FAVORABLE FOR LAKE EFFECT SNOW THAT COULD
BECOME HEAVY. THE TROUGH MAY BROADEN WESTWARD LATER NEXT WEEK
WHILE BECOMING SHALLOWER TO THE EAST. GULF MOISTURE IS FORECAST TO
RETURN TO THE SOUTH-CENTRAL U.S. AND TOWARD THE MID-SOUTH
WEDNESDAY-THURSDAY, AND THEN THERE IS UNCERTAIN POTENTIAL FOR SOME
ORGANIZED WINTRY PRECIPITATION IN THE MIDDLE MISSISSIPPI TO OHIO
VALLEY INTO FRIDAY-SATURDAY TO MONITOR GIVEN COLD CANADIAN FRONTAL
SURGE AND LEAD RETURN FLOW.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE 06 UTC GFS AND 00 UTC ECMWF/UKMET/CANADIAN MODEL SOLUTIONS SEEM
REASONABLY WELL CLUSTERED VALID FOR TUESDAY INTO THURSDAY AND A
COMPOSITE BLEND SEEMS TO PROVIDE A SOLID FORECAST STARTING POINT
GENERALLY IN WITH WPC PRODUCT CONTINUITY IN A PATTERN WITH ABOVE
NORMAL PREDICTABILITY. ADDED GEFS/ECMWF/CANADIAN ENSEMBLE MEANS TO
THE MODEL MIX INTO NEXT FRIDAY/SATURDAY TO BETTER MITIGATE EMBEDDED
SYSTEM VARIANCES CONSISTENT WITH INDIVIDUAL PREDICTABILITY.
UNCERTAINTY DOES ALSO GROW DURING THESE LONGER TIME FRAMES GIVEN
THE AIFS ENSEMBLE MEAN AND GRAPHCAST/AURORA MACHINE LEARNING MODELS
SHOW A RECENT TREND TO SHIFT THE LONGER WAVE PATTERN MORE
PROGRESSIVELY EASTWARD WITH TIME THAN THE STANDARD MODELS AND
ENSEMBLES. HOWEVER, THE PANGO AND FOURCAST MACHINE LEARNING MODELS
ARE MORE IN LINE WITH THE AFOREMENTIONED WPC FAVORED BLEND. WILL
HOLD THERE FOR NOW AS THE PATTERN SEEMS SLOW TO PROGRESS UPSTREAM
TO ME AND THE LATEST 12 UTC MODEL SUITE HAS ALSO HELD COURSE.
..WEATHER/HAZARDS HIGHLIGHTS
SEVERAL DAYS OF LAKE EFFECT AND UPSLOPE FLOW SNOW ARE IN STORE
WITH THE MEAN WESTERLY WIND PATTERN ACROSS THE NORTHEASTERN
QUADRANT OF THE LOWER 48. A CLIPPER SYSTEM COULD SPREAD LIGHT SNOW
TO THE DAKOTAS AND UPPER MIDWEST ON TUESDAY AND ENHANCE GREAT LAKES
SNOW INTO WEDNESDAY/THURSDAY, AND THEN POTENTIALLY SPREAD INTO THE
INTERIOR NORTHEAST ON THURSDAY. SNOW IS FORECAST TO BE HEAVIEST IN
WESTERN NEW YORK DOWNWIND OF LAKE ONTARIO FROM THE LAKE
EFFECT/ENHANCED SNOW, AS SEVERAL INCHES OF SNOW PER DAY COULD
EVENTUALLY PILE UP TO 1-2 FEET.
LATE TUESDAY AND ESPECIALLY BY WEDNESDAY, GULF MOISTURE IS
FORECAST TO MAKE IT INTO SOUTHERN TEXAS IN PARTICULAR AND POOL
ALONG A FRONT. IT IS UNCERTAIN HOW MUCH INSTABILITY COULD REACH
INLAND, AND SOME MODEL GUIDANCE SHOWS THE INSTABILITY AND THUS
HEAVIEST RAIN RATES REMAINING OFFSHORE. SO WHILE THE TEXAS TO
WESTERN LOUISIANA COAST SHOULD SEE SOME RAIN, CONTINUE TO HOLD OFF
FROM ISSUING AN EXCESSIVE RAINFALL AREA ON THE DAY 5/WEDNESDAY ERO
BECAUSE OF THE UNCERTAINTY AND BECAUSE FLOODING IMPACTS MAY NOT BE
LIKELY DUE TO THE DRY ANTECEDENT CONDITIONS. WILL CONTINUE TO
MONITOR. MODERATE RAIN IS FORECAST TO SPREAD INTO THE ARK-LA-TEX TO
LOWER MISSISSIPPI VALLEY WEDNESDAY AND POSSIBLY SOME TO THE MID-
SOUTH AND/OR SOUTHEAST INTO THURSDAY. THEN INTO FRIDAY-SATURDAY,
PRECIPITATION COULD SPREAD ACROSS THE MID-MISSISSIPPI AND OHIO
VALLEYS, INCLUDING POTENTIAL FOR WINTER WEATHER WITH SNOW AND/OR
ICE. THERE IS AMPLE UNCERTAINTY WITH PRECIPITATION COVERAGE, TYPES,
AND AMOUNTS AT THIS POINT THOUGH, SO STAY TUNED FOR FORECAST
UPDATES. MEANWHILE, AREAS OF THE NORTHWEST COULD SEE INCREASING
PRECIPITATION INTO LATER NEXT WEEK WITH ENERGY ALOFT PASSAGE.
WELL BELOW AVERAGE TEMPERATURES ARE EXPECTED ACROSS THE EAST-
CENTRAL U.S. TUESDAY, WITH LOWS IN THE SINGLE DIGITS LIKELY
REACHING AS FAR SOUTH AS KENTUCKY AND EAST TO PENNSYLVANIA, AND
LOWS BELOW -10F IN THE UPPER MIDWEST. CHILLY TEMPERATURES SHOULD
TRACK INTO THE EASTERN SEABOARD ON WEDNESDAY WHILE MODERATING. THEN
REPEATED ROUNDS OF REINFORCING TROUGHING ARE FORECAST ACROSS THE
NORTHERN TIER, LEADING TO BELOW AVERAGE TEMPERATURES IN THE
NORTHERN PLAINS TO UPPER MIDWEST BY FRIDAY AND ESPECIALLY SATURDAY,
WHEN EVEN HIGHS MAY STAY UNDER 0F. MEANWHILE, NEAR TO ABOVE
AVERAGE TEMPERATURES ARE FORECAST ACROSS THE WEST INTO MIDWEEK, BUT
WITH UNCERTAINTY AFTER THAT DEPENDENT ON THE PATTERN ALOFT.
TATE/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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