Quantitative Precipitation Forecast
Issued by NWS

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000
FOUS11 KWBC 280812
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
411 AM EDT SAT MAR 28 2015

VALID 12Z SAT MAR 28 2015 - 12Z TUE MAR 31 2015


DAYS 1-3...

...LONG ISLAND/NEW ENGLAND DAY 1...

MODELS HAVE COME INTO BETTER AGREEMENT SIGNALING A GREATER
POTENTIAL FOR ACCUMULATING SNOWS ACROSS PORTIONS OF EASTERN LONG
ISLAND AND SOUTHERN NEW ENGLAND SAT TO EARLY SUN.  A SURFACE
TROUGH DEVELOPING OFFSHORE BEHIND A LOW THAT IS FORECAST TO TRACK
WELL OFFSHORE IS EXPECTED TO PIVOT ACROSS THE REGION AND PROVIDE
THE FOCUS FOR THE EVENT.  ENHANCED MOISTURE CONVERGENCE ALONG THE
BOUNDARY...INTERACTING WITH THE STRONG COLD AIR ADVECTION ALOFT
AFFORDED BY A DEEP UPPER TROUGH MOVING ACROSS THE REGION...IS
EXPECTED TO CONTRIBUTE TO DEVELOPING SNOWS ACROSS THE REGION.
GIVEN THE MESOSCALE NATURE OF THE EVENT AND THE HIGH SUN ANGLE
THAT LATE MARCH BRINGS...IT IS DIFFICULT TO PINPOINT WHERE...IF
ANY...HEAVY ACCUMULATIONS MIGHT OCCUR.  HOWEVER...THE LATEST
MODELS...INCLUDING THE 00Z ECMWF...SUGGEST SOMEWHERE IN THE
VICINITY OF EASTERN MASS/RI HAS THE GREATEST POTENTIAL.

...GREAT LAKES/NORTHEAST DAYS 2/3...

WARM ADVECTION PRECIPITATION AHEAD OF AN AMPLIFYING SHORTWAVE
TROUGH MOVING THROUGH THE UPPER MIDWEST SUN MORNING...FOLLOWED BY
LAKE EFFECT SHOWS MAY CONTRIBUTE TO SOME LOCALLY HEAVY SNOW
ACCUMULATIONS ACROSS NORTHERN MI DURING THE DAY 2 PERIOD.  WARM
ADVECTION PRECIPITATION IS EXPECTED TO REACH EAST OF THE LOWER
LAKES SUN NIGHT...FOLLOWED BY LAKE EFFECT SOME SNOW SHOWERS BEHIND
THE COLD FRONT AS IT MOVES THROUGH EARLY MON.  THIS MAY PRODUCE
SOME LOCALLY HEAVY AMOUNTS IN THE EASTERN LEE OF LAKE ONTARIO IN
THE TUG HILL PLATEAU REGION DURING THE DAY 3 PERIOD.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

PEREIRA

$$





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