Quantitative Precipitation Forecast
Issued by NWS

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712
FOUS11 KWBC 100931
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
431 AM EST TUE JAN 10 2017

VALID 12Z TUE JAN 10 2017 - 12Z FRI JAN 13 2017


...WESTERN U.S....

PERIODS OF HEAVY SNOW ARE EXPECTED TO CONTINUE WITH SIGNIFICANT
ADDITIONAL ACCUMULATIONS LIKELY ALONG THE SIERRA AND PORTIONS OF
THE NORTHERN AND CENTRAL ROCKIES BEFORE SNOWS BEGIN TO DIMINISH
FROM NORTH TO SOUTH ON THU.  WESTERLY FLOW...TRANSPORTING
ANOMALOUS PACIFIC MOISTURE AND REMNANT MID LEVEL ENERGY ASSOCIATED
WITH A WEAKENING UPPER LOW...IS EXPECTED TO SUPPORT HEAVY SNOWS
FROM THE ORE CASCADES TO THE NORTHERN AND CENTRAL ROCKIES ON
TUE...INCLUDING THE SAWTOOTH OF CENTRAL ID...THE TETONS OF WESTERN
WY AND THE UINTAS AND WASATCH OF NORTHERN UT.  MEANWHILE...AN
UPSTREAM SHORTWAVE ACCOMPANIED BY ANOTHER PLUME OF DEEP MOISTURE
IS EXPECTED TO BRING ADDITIONAL HEAVY PRECIPITATION INTO
SOUTHWESTERN ORE AND NORTHERN CA AS IT MOVES INTO THE REGION ON
TUE.  SNOW LEVELS ARE EXPECTED TO INCREASE AHEAD OF THE SYSTEM TUE
AFTERNOON BEFORE FALLING ONCE AGAIN BY EARLY WED.  EXPECT
ADDITIONAL HEAVY SNOWS FOR THE HIGH SIERRA...WITH MULTIPLE
ADDITIONAL FEET POSSIBLE BY WED MORNING.  AS ONSHORE FLOW
CONTINUES...HEAVY SNOWS ARE EXPECTED TO CONTINUE ALONG THE SIERRA
THROUGH LATE WED.  MEANWHILE...ENERGY AND MOISTURE SPILLING
EASTWARD ARE EXPECTED TO SUPPORT ADDITIONAL HEAVY MOUNTAIN SNOWS
FOR THE RANGES OF WESTERN WY...NORTHERN UT AND WESTERN CO THROUGH
LATE WED AS WELL.  BY EARLY THU...SNOWS ARE FORECAST TO DIMINISH
ACROSS THE NORTHERN SIERRA AND ROCKIES AS A SHORTWAVE APPROACHING
THE WEST COAST CONTINUES TO AMPLIFY WITH A CLOSED LOW DEVELOPING
AND DIGGING SOUTH ACROSS CA.  THIS SYSTEM WILL HAVE LESS MOISTURE
TO WORK WITH...BUT ENOUGH TO PRODUCE SOME MODERATE TO LOCALLY
HEAVY SNOWS ALONG THE CENTRAL AND SOUTHERN SIERRA TO THE HIGHER
ELEVATIONS OF THE SOUTHERN GREAT BASIN AND THE ROCKIES OF WESTERN
CO.

...UPPER MIDWEST/GREAT LAKES/NORTHEAST...

A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN AND CENTRAL PLAINS
TUE MORNING IS EXPECTED TO ASSUME A NEGATIVE TILT AS IT MOVES
ACROSS THE UPPER AND MID MS VALLEY LATER IN THE DAY.  STRONG LOW
LEVEL WARM ADVECTION AHEAD OF A DEEPENING SURFACE LOW IS EXPECTED
TO SUPPORT SNOW CHANGING TO THE RAIN FROM LOWER MI TO UPSTATE NY
AND NORTHERN NEW ENGLAND.  SOME LIGHT TO MODERATE ACCUMULATIONS OF
4-INCHES OR MORE ARE POSSIBLE ACROSS NORTHERN LOWER MI...AS WELL
AS THE ADIRONDACKS AND THE WHITE MOUNTAINS BEFORE THE CHANGEOVER
TO RAIN.  WEST OF THE LOW TRACK WHERE PRECIPITATION IS EXPECTED TO
REMAIN ALL SNOW...FAVORABLE UPPER JET DYNAMICS ALONG WITH WITH LOW
TO MID LEVEL FRONTOGENESIS MAY SUPPORT SOME LOCALLY HEAVY
ACCUMULATIONS ACROSS NORTHERN WI INTO THE U.P. OF MI...WHERE
ACCUMULATIONS MAY EXCEED 8-INCHES ON TUE.

PEREIRA

$$





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