Quantitative Precipitation Forecast
Issued by NWS

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FOUS11 KWBC 302003
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
402 PM EDT THU MAR 30 2017

VALID 00Z FRI MAR 31 2017 - 00Z MON APR 03 2017

DAYS 1 THROUGH 3...

...GREAT BASIN/ROCKIES...

A VERY STRONG UPPER SHORTWAVE BEGINNING TO DIG INTO THE GREAT
BASIN THIS AFTN WILL PROCEED TOWARDS THE FOUR CORNERS REGION ON
FRI. THIS POTENT FEATURE WILL THEN CLOSE OFF A MID TO UPPER LOW
AND DETACH FROM THE WESTERLIES. THIS FORECAST SCENARIO OVERALL
WILL SET THE STAGE FOR WIDESPREAD HEAVY SNOWFALL ACROSS PARTS OF
THE WESTERN TERRAIN AND POSSIBLY BLEED OUT INTO THE CENTRAL HIGH
PLAINS. THE HEAVY SNOWFALL FORECAST FROM THURS EVENING TO FRI
EVENING WILL FEATURE TREMENDOUS VERTICAL LIFT FROM A VERY ACTIVE
UPPER JET AND BROAD UPPER DIFLUENCE. STRONG ERLY TO SERLY MOIST
UPSLOPE FLOW WILL INUNDATE WY... WHILE A VERY IMPRESSIVE THERMAL
FRONT SWEEPS ALMOST ENTIRELY THROUGH THE FOUR CORNERS REGION. THE
FAVORED TERRAIN OF THE BIG HORNS/WIND RIVER RANGE OF WY AND
CENTRAL/SRN WASATCH OF UT INTO SAN JUANS. IN FACT... THE GFS AND
ECMWF SUGGEST THE WIND RIVER RANGE MOST PRONE TO POSSIBLY 2 FEET
OF SNOW OR MORE WITH 1.5 TO 2 INCH LIQUID QPF AMOUNTS. THE
FOCUS... ON FRI EVENING TO SAT EVENING/SUN MORNING... WILL SHIFT
TO THE CENTRAL ROCKIES AND ATTEMPT TO SPREAD OUT INTO THE HIGH
PLAINS... THOUGH LARGE SPREAD WITH THERMALS/PTYPE OVER ERN CO INTO
WRN NE/KS. WPC FAVORED THE ECMWF MORE THAN THE GFS ON QPF AND
THERMALS... WHICH REALLY KEEPS THE HEAVIEST SNOWS IN THE CO
ROCKIES WITH MORE MINIMAL ACCUMULATIONS SPREADING DOWN THE ERN
SLOPE INTO DEN/BOU. OVERALL SOME RATHER IMPRESSIVE ACCUMULATIONS
ARE EXPECTED OVER THE TWO DAYS.

...NEW ENGLAND...

THE LARGE SCALE LOW PRESSURE SYSTEM OVER THE MIDWEST AND MOVING
INTO THE EAST TODAY WILL POSSIBLY PRODUCE A LATE SEASON HEAVY SNOW
EVENT FOR UPSTATE NY AND PARTS OF NEW ENGLAND ON FRI AND SAT. ON
FRI... THE LOW PRESSURE SYSTEM AND CLOSED MID TO UPPER LOW SLIDE
THROUGH THE OH VALLEY INTO THE NRN MID-ATL REGION... WHILE A
DISTINCT FRONTAL BOUNDARY TO THE NORTH OF THE SYSTEM ENHANCES QPF
FROM LAKE ONTARIO INTO INTERIOR PARTS OF THE NORTHEAST. THIS WILL
ENHANCE A WEDGING AREA OF SURFACE HIGH PRESSURE AND COOLS THE
ENTIRE COLUMN FOR AN AXIS OF HEAVY SNOW FROM UPSTATE NY AND
ADIRONDACKS INTO PARTS OF WT/NH/MA OR WHITE/GREEN MTNS AND
BERKSHIRES. THEN FRI EVENING... A FRESH AREA OF LOW PRESSURE WILL
FORM NEAR THE DELMARVA AND TRACK JUST SOUTH OF THE SRN NEW ENGLAND
COASTLINE ON SAT. THERE IS SPREAD WITH THE LATITUDE OF THE
DEEPENING AREA OF LOW PRESSURE... WITH THE GFS BEING A SOUTHERN
OUTLIER AND COLDER THERMAL SOLUTION. WPC STAYED RELATIVELY CLOSE
THE ECMWF FOR HEAVY SNOW PROBS OVER A LARGE PART OF NEW ENGLAND
WITH THE HEAVIEST ACCUMULATIONS OVER VT/NH.

MUSHER



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