541
FOUS11 KWBC 062040
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
340 PM EST TUE JAN 6 2026
VALID 00Z WED JAN 07 2026 - 00Z SAT JAN 10 2026
..NORTHEAST
DAY 1...
AN AMPLIFYING SHORTWAVE ALONG WITH A TRAILING SHORTWAVE OVER THE
UPPER MIDWEST THIS EVENING WILL MOVE STEADILY EASTWARD INTO/THROUGH
THE NORTHEAST OVERNIGHT AND EARLY TOMORROW MORNING. AS A MODEST
JET STREAK MOVES OFF THE MID-ATLANTIC COAST THIS EVENING, BROAD
LIFT ON THE POLEWARD SIDE OF THE JET WILL HELP PROMOTE AN EXPANDING
AREA OF PRECIPITATION ACROSS THE REGION ATOP A MARGINAL TO COLD
ENVIRONMENT. AT THE SURFACE, THE DUELING MID-LEVEL SHORTWAVES WILL
HELP TAKE A LEAD SURFACE LOW OVER WESTERN NY (BUF TO ART)
OVERNIGHT AND A NEWLY DEVELOPING SURFACE LOW NEAR SOUTHEAST MASS BY
12Z WED THAT WILL LIFT TOWARD NOVA SCOTIA THROUGH THE AFTERNOON.
GIVEN THE MARGINAL TEMPERATURES AT PRECIP ONSET OVER AT LEAST SOME
OF THE INTERIOR AND WAA ALOFT, A MIX OF FREEZING RAIN AND SOME
SLEET TO THE SOUTH AND MOSTLY SNOW TO THE NORTH (ALONG THE CANADIAN
BORDER) IS LIKELY AS THE DECAYING LEAD LOW ALLOWS A NORTHERLY
FETCH TO CONTINUE TO BRING IN SOME COLDER AIR TO NORTHERN
LOCATIONS. THE SYSTEM WILL EXIT THE REGION BY TOMORROW EVENING
GIVEN THE PROGRESSIVE FLOW.
FOR AREAS THAT RECEIVE MOSTLY SNOW (THE HIGHER ELEVATIONS OF THE
ADIRONDACKS AND NORTHERN NEW ENGLAND), WPC PROBABILITIES FOR AT
LEAST 4 INCHES OF SNOW ARE MODEST AT 10-40% WITH MOST AREAS LIKELY
SEEING 2-3 INCHES OF SNOW. ALONG AND SOUTH OF I-90, A MIX OF MOSTLY
FREEZING RAIN BUT SOME SLEET IS LIKELY. WPC PROBABILITIES OF AT
LEAST 0.10" ICING ARE HIGHEST (>50%) IN MA ALONG/NORTH OF I-90 AND
ALONG ROUTE 2, AS WELL AS INTO THE SOUTHERN GREEN MOUNTAINS IN VT
AND INTO SOUTHERN NH. LOCALIZED AMOUNTS NEAR 0.25" ARE POSSIBLE.
..OLYMPICS, CASCADES, GREAT BASIN, AND NORTHERN/CENTRAL ROCKIES
DAYS 1-3...
THE STRONG JET ACROSS THE NORTH PACIFIC WILL DIP INTO THE PAC NW
AND WEAKEN, BUT STILL BRING A MODEST INFLUX OF MOISTURE TO THE
REGION VIA SEVERAL EMBEDDED SHORTWAVES. LEAD SYSTEM ENTERS TONIGHT
VIA A 120KT JET STREAK WITH SNOW TO THE CASCADES AND NORTHERN
ROCKIES THAT WILL SINK SOUTHWARD AS THE JET DIGS AND DIPS THROUGH
THE GREAT BASIN. SNOW LEVELS INITIALLY AROUND 3000-4000FT WILL
LOWER OVERNIGHT TO BELOW 2000FT (WA AND EASTWARD) AND 3000FT (OR TO
ID) BY TOMORROW MORNING, WITH ANOTHER SURGE IN MOISTURE THEREAFTER
AS THE SECOND SHORTWAVE MOVES IN FROM THE PACIFIC. SNOW LEVELS
WILL CONTINUE TO LOWER TO AS LOW AS 750-1000FT BY EARLY THURSDAY AS
PRECIPITATION LIGHTENS AND IS INCREASINGLY FAVORED IN THE TERRAIN.
HOWEVER, THIS WILL BRING IMPACTFUL SNOW TO THE PASSES AND AT LEAST
SOME LIGHT SNOW TO SOME HIGHER LOWLAND AREAS AROUND 1000FT.
PRECIPITATION SHOULD END IN THE PACNW BY FRIDAY AFTERNOON. WPC
PROBABILITIES ARE >50% FOR AT LEAST 8 INCHES OF SNOW ABOVE
1000-2000FT THROUGH THE WA/OR CASCADES AND FOR AT LEAST 18 INCHES
OF SNOW ABOVE 2000-3000FT. TOTAL SNOW FOR THE HIGHEST PEAKS MAY
ECLIPSE 3-4FT.
FROM THE NORTHERN ROCKIES SOUTHWARD TO THE WASATCH AND WY RANGES,
MOISTURE ASSOCIATED WITH THE PACIFIC INTRUSION WILL STILL BE MODEST
BUT SUFFICIENT ENOUGH TO CAPITALIZE ON UPSLOPE ENHANCEMENT INTO
THE TERRAIN, ESPECIALLY OVER IDAHO AND NORTHWESTERN MT D1 THEN
THROUGH WESTERN WY AND EVENTUALLY THE WASATCH AS THE MOISTURE AND
TROUGH SINK SOUTHWARD AND EASTWARD. WPC PROBABILITIES FOR AT LEAST
12 INCHES OF SNOW ARE >50% ABOVE 4000-5000FT (NORTH), 7000FT (WY),
AND 7000-8000FT (WASATCH).
..FOUR CORNERS STATES
DAYS 2-3...
A VIGOROUS SHORTWAVE DIGGING SOUTHEAST FROM THE PACIFIC NORTHWEST
WILL AMPLIFY RAPIDLY AS IT APPROACHES THE FOUR CORNERS STATES
(POTENTIALLY CLOSING OFF OVER THE HIGH PLAINS OF SOUTHEAST CO AND
NORTHEAST NM OR VICINITY) THURSDAY INTO FRIDAY, BEFORE EJECTING
EASTWARD INTO THE CENTRAL PLAINS FRIDAY NIGHT INTO SATURDAY. AS
THIS OCCURS, A STRENGTHENING 120KT+ 250MB JET OVERSPREADING THE
SOUTHERN AND CENTRAL PLAINS WILL BEGIN TO ARC POLEWARD, PLACING THE
LEFT EXIT REGION IN THE VICINITY OF THE CENTRAL AND SOUTHERN
ROCKIES. THE OVERLAP OF LEFT EXIT REGION DIFFLUENCE WITH MID-LEVEL
HEIGHT FALLS WILL LIKELY LEAD TO LEE SIDE CYCLOGENESIS THURSDAY
EVENING, WITHIN A COLUMN THAT, WHILE WILL FEATURE GENERALLY NORMAL
TO BELOW NORMAL PWS, WILL SATURATE IN RESPONSE TO INCREASING LOW-
LEVEL EASTERLY FLOW AROUND THE STRENGTHENING SURFACE LOW. WITH
STEEP LAPSE RATES ALOFT HELPING TO COOL THE COLUMN, AND FLOW
BECOMING INCREASINGLY FAVORABLE TO UPSLOPE INTO THE TERRAIN,
CONFIDENCE IS INCREASING FOR A MORE SIGNIFICANT SNOW EVENT FOR MUCH
OF THE CENTRAL AND SOUTHERN ROCKIES INTO THE HIGH PLAINS OF CO/NM,
INCLUDING THE I-25 CORRIDOR (PARTICULARLY FROM DENVER TO COLORADO
SPRINGS) WHICH HAS EXPERIENCED A RELATIVE DEARTH OF SNOWFALL SO FAR
THIS SEASON.
WHILE ADJUSTMENTS IN THE FORECAST ARE LIKELY (AND THE LATEST
TRENDS SUGGEST THOSE ADJUSTMENTS ARE LIKELY TO BE UPWARD), CURRENT
WPC SNOW PROBABILITIES NOW INDICATE A HIGH RISK (>70% CHANCE) FOR
STORM TOTAL ACCUMULATIONS OF 8+ INCHES OF SNOW ACROSS MUCH OF THE
CO ROCKIES (INCLUDING THE FRONT RANGE), PORTIONS OF THE WASATCH,
AND SOUTHWARD INTO THE HIGHER ELEVATIONS OF NORTHEAST AZ AND
NORTHWEST NM. THE LOWER ELEVATIONS OF I-25 AND INTO THE HIGH PLAINS
NOW HAVE A 30-60% CHANCE OF 4+ INCHES, ALTHOUGH LOCALLY HIGHER
AMOUNTS, POTENTIALLY IN EXCESS OF 8 INCHES, ARE ALSO POSSIBLE
ACROSS WESTERN PORTIONS OF THE PALMER DIVIDE AND RATON MESA.
FRACASSO/MILLER/WEISS
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