128
FOUS11 KWBC 200701
QPFHSD
PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
301 AM EDT FRI MAR 20 2026
VALID 12Z FRI MAR 20 2026 - 12Z MON MAR 23 2026
..UPPER GREAT LAKES TO THE NORTHEAST
DAYS 1-3...
THE FIRST IN A SERIES OF CLIPPER SYSTEMS WILL PRODUCE PERIODS OF
SNOW ACROSS NORTHERN NEW YORK AND NORTHERN NEW ENGLAND TODAY. LOW-
LEVEL WAA AHEAD OF THE CLIPPER WILL SUPPORT PERIODS OF SNOW, EVEN
DOWN TO THE VALLEY FLOORS IN NORTHERN NEW ENGLAND. HOWEVER,
SNOWFALL RATES AND ELEVATION WILL PLAY CRITICAL ROLES IN SNOWFALL
ACCUMULATIONS. MOST NOTABLY, THE ADIRONDACKS, GREEN, AND WHITE
MOUNTAINS ARE MOST FAVORED FOR >1"/HR SNOWFALL RATES. WPC
PROBABILITIES DEPICT LOCALIZED MODERATE PROBABILITIES (40-60%) FOR
SNOWFALL TOTALS >4" WITH THE PEAKS OF THESE MOUNTAIN RANGES
(INCLUDING MT. WASHINGTON) SPORTING LOW CHANCES (10-30%) FOR
SNOWFALL ACCUMULATIONS AS HIGH AS 6". OTHERWISE, MOST ELEVATIONS
BELOW 1,000FT ARE LIKELY TO SEE ANYWHERE FROM A COATING TO AS MUCH
AS 3". THE WSSI DOES DEPICT SOME MINOR IMPACT POTENTIAL,
PARTICULARLY IN THE ADIRONDACKS AND BORDERING THE ST. LAWRENCE
RIVER IN NY'S NORTH COUNTRY. SNOW WILL TAPER OFF ACROSS NORTHERN
NEW ENGLAND BY FRIDAY NIGHT.
AS THIS CLIPPER EXITS TO THE EAST SATURDAY MORNING, THE NEXT
CLIPPER SYSTEM IS ALREADY MAKING ITS WAY TOWARDS THE UPPER GREAT
LAKES. THERE REMAINS A DECENT AMOUNT OF MODEL SPREAD IN THE
AMPLITUDE AND PROGRESSION OF THIS CLIPPER, LARGELY BECAUSE IT IS
ESSENTIALLY AN UNORGANIZED CLUSTER OF SHEARED 500MB VORT MAXIMA
TRACKING OVER THE NORTHERN GREAT LAKES AND NORTHEAST. THERE WILL BE
SUFFICIENT UPPER-LEVEL ASCENT THANKS TO THE LEFT-EXIT REGION OF A
500MB JET STREAK WILL ACCOMPANY THE CLIPPER. THERE IS ALSO
AGREEMENT ON MODEL GUIDANCE ON HEALTHY 850-700MB WAA VIA WSWRLY
FLOW THAT COLLIDES WITH SUFFICIENTLY COLD BOUNDARY LAYER
TEMPERATURES OVER NORTHERN NY AND THE REST OF NORTHERN NEW
ENGLAND. HOWEVER, GUIDANCE IS NOT YET IN AGREEMENT ON WHERE THE
STRONGEST 850-700MB FGEN TAKES SHAPE, AND AS A RESULT, DISAGREE ON
THE PLACEMENT OF THE QPF AXIS TO THE NORTH OF THE STORM TRACK. WPC
DAY 3 CLUSTER ANALYSIS SHOWS THE DEPARTING TROUGH OVER NOVA SCOTIA
AND THE DEPTH OF THE PRIMARY 500MB SHORTWAVE TROUGH OVER THE UPPER
MIDWEST ARE THE MOST SENSITIVE FACTORS IN DETERMINING WHAT THIS
CLIPPER ULTIMATELY PRODUCES, AND BECAUSE OF THE NOTABLY SHORTER
WAVELENGTHS, CONFIDENCE IN WHERE THE HEAVIEST SNOWFALL WILL OCCUR
IS NOT CLEAR OUT TO DAY 3.
SO WHAT WE DO KNOW-- IT IS LATE MARCH AND ELEVATION MATTERS A TON.
HOWEVER YOU SLICE IT ACROSS DETERMINISTIC GUIDANCE OR
PROBABILISTIC GUIDANCE, THE ADIRONDACKS, GREEN, WHITES, AND
BERKSHIRES ARE MOST FAVORED FOR ACCUMULATING SNOWFALL. EVEN AS FAR
WEST AS THE MI U.P. AND MN ARROWHEAD, SNOWFALL TOTALS APPROACHING
4" ARE POSSIBLE. WPC PROBABILITIES SHOW LOW-TO-MODERATE CHANCES
(30-50%) FOR SNOWFALL TOTALS >4" IN THE HURONS OF THE MI U.P.
BETWEEN SATURDAY NIGHT AND THROUGH SUNDAY. FARTHER EAST, THE
>2,000FT ELEVATIONS IN THE ADIRONDACKS, GREENS, AND WHITES SPORT
MODERATE CHANCES (40-60%) FOR SNOWFALL TOTALS >8" ON SUNDAY. BELOW
1,000FT, PROBABILITIES FOR SNOWFALL AMOUNTS >4" ARE LOW (10-30%)
WITH MOST ACCUMULATIONS LESS THAN 4" EXPECTED AT THIS TIME. WPC'S
WSSI-P DEPICTS MODERATE CHANCES (40-60%) FOR MINOR IMPACTS IN THE
MN ARROWHEAD TO MUCH OF NORTHERN MI DUE TO A COMBINATION OF SNOW
AND ICE (WPC PROBABILITIES SHOW LOW-TO-MODERATE CHANCES, OR 30-50%,
FOR ICE ACCUMULATIONS OF AT LEAST ONE-HUNDRETH OF AN INCH) LATE
SATURDAY INTO EARLY SUNDAY. MINOR PROBABILITIES ARE HIGHEST IN
NORTHERN NEW ENGLAND WHERE MODERATE PROBABILITIES (40-60%) ARE
PRESENT THROUGHOUT THE NORTHERN APPALACHIANS. IN FACT, SOME
LOCALIZED 40-50% PROBABILITIES FOR MODERATE IMPACTS ARE SHOWN
ACROSS SOUTH-CENTRAL AND DOWNEAST MAINE.
THE CHANCES FOR SIGNIFICANT ICING ACROSS THE CONUS IS LESS THAN 10
PERCENT.
MULLINAX
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