Quantitative Precipitation Forecast
Issued by NWS

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FOUS11 KWBC 262053
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
453 PM EDT SUN MAR 26 2017

VALID 00Z MON MAR 27 2017 - 00Z THU MAR 30 2017

DAYS 1 THROUGH 3...

...WESTERN U.S....

MOUNTAIN SNOWS WILL CONTINUE OVER PORTIONS OF THE WESTERN U.S.
EARLY THIS WEEK...WITH THE CASCADES...UINTA/WASATCH RANGES IN
UTAH...AND COLORADO ROCKIES EXPECTED TO SEE THE GREATEST CHANCE
FOR SNOWFALL ACCUMULATIONS IN EXCESS OF A FOOT.

AN UPPER TROUGH AND ASSOCIATED COLD FRONT PRESSING INLAND OVER THE
NORTHWESTERN U.S. SUNDAY EVENING WILL BE THE INITIAL FOCUS FOR
SNOWFALL.  THE COMBINATION OF LOWERING SNOW LEVELS AND MOIST FLOW
INTO THE TERRAIN SHOULD BRING MODERATE TO LOCALLY HEAVY SNOW TO
THE HIGHER ELEVATIONS OF THE OLYMPICS AND CASCADES...AND ACTIVITY
SHOULD SPREAD INTO THE BOISE/SALMON RIVER MOUNTAINS AND SIERRA
NEVADA RANGE AS THE COLD FRONT PROGRESSES SOUTHEASTWARD SUNDAY
NIGHT INTO MONDAY.

MONDAY INTO TUESDAY...THE UPPER TROUGH IS EXPECTED TO AMPLIFY
WHILE CONTINUING TO DIG SOUTHEASTWARD AND EVENTUALLY CLOSE OFF AN
UPPER LOW NEAR THE SOUTHWEST/FOUR CORNERS REGION.  THE SHARPENING
UPPER TROUGH SHOULD HELP TRIGGER PERIODS OF MODERATE TO HEAVY SNOW
OVER THE WASATCH/UINTA RANGES IN UTAH AS WELL AS THE COLORADO
ROCKIES...ESPECIALLY ALONG THE FRONT RANGE ONCE A SURFACE LOW
DEEPENS OVER THE SOUTHERN HIGH PLAINS AND UPSLOPE FLOW INCREASES
ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.

MEANWHILE...QUASI-ZONAL FLOW SETTING UP OVER THE NORTHWEST BEHIND
THE AMPLIFYING UPPER TROUGH SHOULD ALLOW SNOW TO CONTINUE OVER THE
OLYMPICS AND WASHINGTON CASCADES MONDAY AND TUESDAY...WITH SNOW
BECOMING POTENTIALLY HEAVY ALONG THE CASCADES AS A SURGE OF
MOISTURE AHEAD OF ANOTHER UPPER TROUGH APPROACHES THE NORTHWEST
TUESDAY NIGHT INTO WEDNESDAY.

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


...NEW YORK AND NEW ENGLAND...

FREEZING RAIN IS EXPECTED FOR PORTIONS OF NEW YORK AND NEW ENGLAND
SUNDAY NIGHT INTO MONDAY AS A WEAKENING UPPER TROUGH LIFTS FROM
THE OHIO VALLEY TO THE GREAT LAKES AND NORTHEAST.  SURFACE HIGH
PRESSURE INITIALLY CENTERED OVER SOUTHEAST CANADA ON SUNDAY SHOULD
REINFORCE LOW LEVEL COLD AIR AND ALLOW FOR PERIODS OF FREEZING
RAIN WITHIN THE NORTHERN EDGE OF WARM ADVECTION PRECIPITATION
DEVELOPING AHEAD OF THE WEAKENING UPPER LOW.  SNOW WILL ALSO BE
POSSIBLE WITH THIS EVENT...WITH LIGHT ACCUMULATIONS EXPECTED OVER
NORTHERN MAINE.  ANOTHER ROUND OF ACCUMULATING SNOW WILL BE
POSSIBLE OVER PORTIONS OF MAINE TUESDAY NIGHT INTO WEDNESDAY.
HOWEVER....THE FORECAST REMAINS VERY UNCERTAIN WITH THE
PHASING/INTERACTIONS OF WEAK SHORTWAVE ENERGY AND POSSIBLE SURFACE
WAVE DEEPENING OFF THE NORTHEAST COAST.  PLEASE REFER TO WPC`S
MODEL DIAGNOSTIC DISCUSSION (PMDHMD) FOR MORE DETAILS ON MODEL
SPREAD.

WPC PROBABILISTIC GUIDANCE CONTINUES TO SHOW A SLIGHT RISK (AT
LEAST 10% PROBABILITY) OF ICE ACCUMULATIONS EXCEEDING 0.25" OVER
PORTIONS OF NORTHERN NEW HAMPSHIRE AND WESTERN MAINE.


GERHARDT


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