Quantitative Precipitation Forecast
Issued by NWS

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084
FOUS11 KWBC 042050
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
350 PM EST THU FEB 04 2016

VALID 00Z FRI FEB 05 2016 - 00Z MON FEB 08 2016


DAYS 1 THROUGH 3...

...COASTAL NORTHEAST/MIDDLE ATLANTIC...

AN AMPLIFIED UPPER TROUGH EXTENDING FROM THE UPPER MS VALLEY TO
THE CENTRAL GULF COAST WILL SHIFT TO THE EAST AND EASTERN SEABOARD
OVER THE NEXT 24 HRS. UPPER DYNAMICS IN THE BASE OF THE UPPER
TROUGH AXIS... NEAR LOWER MS VALLEY AT THE MOMENT... IS EXPECTED
TO INTENSIFY AND REACH THE MID-ATL/NC COAST BY FRI MORNING.
MEANWHILE... A WEAKER SHORT WAVE ALONG THE NRN STREAM IS DIGGING
ACROSS THE WRN GREAT LAKES INTO THE OH VALLEY BY FRI MORNING. THE
TWO STREAMS WILL ATTEMPT TO PHASE... TAKE A NEG TILT WITH BACKING
FLOW... INDUCE AN AREA OF LOW PRESSURE ALONG OR JUST OFFSHORE OF
NC AND POSSIBLY ALLOW A BURST OF HEAVY SNOWFALL ON THE BACKSIDE OF
THE SYSTEM OR EDGE OF THE ANTICIPATED STREAM OF QPF. THE DEFINITE
TREND OVER THE LAST 24 HRS CONTINUES TO INDICATE A NORTH AND WEST
SHIFT TO THE QPF... AS THE SURFACE WAVE RACES TOWARD THE BENCH
MARK OVER THE ATLANTIC. A FORECAST THIS CLOSE WITH VERY NARROW
SPREAD AMONGST THE OPERATIONAL MODELS SUGGESTS HIGH CONFIDENCE BUT
AND IT`S A BIG BUT IS THE SPLIT FLOW AND TIMING OF PHASING IS
ALWAYS VERY DIFFICULT. WPC WENT AHEAD WITH A STRIPE OF
ACCUMULATIONS FROM THE NORTHERN NECK OF VA/MD EASTERN SHORE
THROUGH DE/NJ/EXTREME SERN PA INTO POTENTIALLY NYC AND MOST OR ALL
OF SERN NEW ENGLAND. ITS THE LATTER SPOT OF ERN/SERN MA/CAPE COD
AND RI/NERN CT TO EXTREME ERN MAINE WHERE POSSIBLE ACCUMULATIONS
COULD BE MORE SIGNIFICANT BEFORE THE PHASED SYSTEM DEPARTS THE ERN
SEABOARD.

...PACIFIC NORTHWEST/INTER-MOUNTAIN WEST TO UPPER MIDWEST...

A PROGRESSIVE PAC SHORT WAVE WILL SLIDE THROUGH THE PAC NW INTO
THE NRN ROCKIES LATE FRI THROUGH SAT. REASONABLE PAC MOISTURE
TRANSPORT ACCOMPANYING THE SYSTEM SHOULD RESULT IN HEAVY SNOWFALL
FROM THE WA CASCADES INTO THE NRN ROCKIES AND BITTERROOTS. THIS
PAC SYSTEM WILL TEAM WITH THE NRN STREAM AND TRACK ALONG THE
US/CANADIAN BORDER NEAR THE UPPER MIDWEST LATE SAT THROUGH SUN.
THE BULK OF THE HEAVY OVERRUNNING SNOW SHOULD OCCUR ACROSS CANADA
BUT A BLEND OF THE GFS/ECMWF SUGGESTS A FEW INCHES POSSIBLE FROM
ND INTO MN/WI AND THE UP OF MI.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

MUSHER


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