Quantitative Precipitation Forecast
Issued by NWS

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FOUS11 KWBC 252059
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
459 PM EDT SAT MAR 25 2017

VALID 00Z SUN MAR 26 2017 - 00Z WED MAR 29 2017

DAYS 1 THROUGH 3...

...WESTERN U.S....

ADDITIONAL PERIODS OF HIGHER ELEVATION SNOW WILL BE POSSIBLE FROM
THE PACIFIC NORTHWEST AND CALIFORNIA TO THE ROCKIES AS MULTIPLE
MID/UPPER-LEVEL TROUGHS TRAVERSE THE WESTERN U.S. THIS WEEKEND AND
EARLY NEXT WEEK.

THE FIRST SHORTWAVE IS EXPECTED TO QUICKLY PROGRESS FROM CENTRAL
GREAT BASIN TO THE CENTRAL PLAINS SATURDAY NIGHT INTO
SUNDAY...TRIGGERING MAINLY LIGHT TO LOCALLY MODERATE SNOW ACROSS
THE RANGES OF NORTHERN WYOMING (BIGHORNS) AND THE COLORADO
ROCKIES.

UPSTREAM...THE NEXT UPPER TROUGH AND ASSOCIATED COLD FRONT SHOULD
BEGIN PRESSING INLAND OVER THE WESTERN U.S. ON SUNDAY.  MOIST FLOW
INTO THE TERRAIN SHOULD BRING PERIODS OF MODERATE TO HEAVY SNOW TO
THE WINDWARD TERRAIN OF THE CASCADES AND SIERRA NEVADA
RANGE...BEFORE THE FOCUS FOR ACTIVITY SHIFTS EASTWARD INTO THE
NORTHERN/CENTRAL ROCKIES AND CENTRAL GREAT BASIN AS THE UPPER
TROUGH AMPLIFIES AND PRESSES FARTHER INLAND MONDAY INTO TUESDAY.
HOWEVER...QUASI-ZONAL SETTING UP OVER THE NORTHWEST BEHIND THE
AMPLIFYING UPPER TROUGH SHOULD ALLOW MODERATE TO HEAVY SNOW TO
CONTINUE THROUGH TUESDAY OVER THE OLYMPICS AND WASHINGTON
CASCADES.

THE PROBABILITY OF RECEIVING A QUARTER INCH OF FREEZING RAIN IS
LESS THAN 10 PERCENT ACROSS THE WESTERN US.


...GREAT LAKES TO THE NORTHEAST...

A LATE SEASON FREEZING RAIN EVENT IS EXPECTED FOR PORTIONS OF THE
UPPER GREAT LAKES AND NEW ENGLAND OVER THE NEXT FEW DAYS AS A
WEAKENING UPPER LOW LIFTS FROM THE MIDDLE MISSISSIPPI VALLEY TO
THE LOWER GREAT LAKES AND NORTHEAST.  AN ARCTIC AIRMASS INITIALLY
CENTERED OVER SOUTHERN QUEBEC SATURDAY EVENING SHOULD HOLD ON LONG
ENOUGH TO SUPPORT FREEZING RAIN WITHIN THE NORTHERN EDGE OF WARM
ADVECTION PRECIPITATION DEVELOPING AHEAD THE WEAKENING UPPER
LOW...WHICH IS EXPECTED TO SPREAD NORTHWARD THROUGH THE UPPER
GREAT LAKES SATURDAY NIGHT INTO SUNDAY BEFORE SLOWLY LIFTING
NORTHEASTWARD FROM NORTHERN NEW YORK TO NORTHERN MAINE SUNDAY
THROUGH EARLY TUESDAY.  SNOW WILL ALSO BE POSSIBLE WITH THIS
SYSTEM...BUT ACCUMULATIONS SHOULD BE MOSTLY CONFINED TO THE
NORTHERN HALF OF MAINE.

WPC PROBABILISTIC GUIDANCE SUGGESTS THE GREATEST POTENTIAL FOR
ACCUMULATING FREEZING RAIN WILL BE OVER NORTHERN WISCONSIN...THE
U.P. OF MICHIGAN...ADIRONDACK AND CATSKILLS REGIONS OF NEW
YORK...AS WELL AS INTERIOR NEW ENGLAND...WITH A SLIGHT RISK (AT
LEAST 10% PROBABILITY) OF ICE ACCUMULATIONS GREATER THAN 0.25"
OVER PORTIONS OF NORTHERN NEW HAMPSHIRE AND WESTERN MAINE.
HOWEVER...THE STRENGTH OF THE LOW-LEVEL WARM ADVECTION...ALONG
WITH THE STRENGTH OF THE ARCTIC HIGH ACROSS SOUTHEASTERN CANADA
WILL DETERMINE THE EXACT DISTRIBUTION OF PRECIPITATION TYPES AND
AMOUNTS DURING THIS EVENT.


GERHARDT


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