Quantitative Precipitation Forecast
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FOUS11 KWBC 010823
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
322 AM EST THU DEC 01 2016

VALID 12Z THU DEC 01 2016 - 12Z SUN DEC 04 2016

DAY 1 TO 3...

...PACIFIC NORTHWEST/NORTHERN INTER-MOUNTAIN WEST...

PERIODS OF SNOW WILL LIKELY CONTINUE ACROSS THE CASCADES OF
WESTERN WA INTO THE HIGHER TERRAIN OF NORTHERN ID AND WESTERN MT
THROUGH SATURDAY NIGHT. LIKELY TO SEE AN UPTICK IN INTENSITY ON
FRIDAY AS A SHORTWAVE AND FRONT MOVES ACROSS...AND ANOTHER
INCREASE BY SATURDAY NIGHT AS AN EVEN STRONGER SURGE OF ONSHORE
UPSLOPE FLOW AND SYNOPTIC FORCING MOVES ACROSS THE REGION. OVER
THE 72 HOUR PERIOD THROUGH SATURDAY NIGHT HAVE HIGH PROBABILITIES
OF 8"+ ACROSS THE CASCADES INTO PORTIONS OF NORTHERN ID AND
WESTERN MT...WITH A GOOD CHANCE OF 18"+ ACROSS PORTIONS OF THE
CASCADES.

LIGHTER SNOWFALL AMOUNTS ARE EXPECTED TODAY ACROSS THE HIGHER
TERRAIN OF NORTHWEST WY AND NORTHERN UT AS A MOISTURE STARVED
SHORTWAVE MOVES ACROSS THE REGION. AMOUNTS ARE GENERALLY EXPECTED
TO STAY IN THE 2-6" RANGE.

...NORTHERN MAINE/EASTERN GREAT LAKES...

MODERATE TO TO HEAVY SNOW IS EXPECTED TODAY ACROSS NORTHERN MAINE
AS AN AREA OF LOW PRESSURE FORMS AND MOVES NORTHEASTWARD JUST OFF
THE COAST. RAIN ACROSS THE SOUTHERN PORTION OF THE STATE WILL
QUICKLY TRANSITION TO ACCUMULATING SNOW AS YOU HEAD NORTH.
CONTINUE TO SHOW HIGH PROBABILITIES OF 8"+ ACROSS NORTHERN MAINE
FROM THIS SYSTEM.

SOME LAKE EFFECT PRECIPITATION IS EXPECTED TODAY INTO SATURDAY IN
THE NORTHWESTERLY FLOW BEHIND THE DEPARTING LOW PRESSURE.
TEMPERATURES ALOFT AND AT THE SURFACE WILL NOT BE ALL THAT COLD.
THUS WOULD GENERALLY EXPECT TO SEE A RAIN SNOW MIX...WITH THE BEST
CHANCE OF ACCUMULATING SNOW AWAY FROM THE LAKE SHORE. GIVEN THE
MARGINAL TEMPERATURES WOULD ALSO LIKELY NEED TO HAVE THE SNOW
FALLING AT A DECENT CLIP FOR THERE TO BE MUCH ACCUMULATION. THE
BEST CHANCE OF ACCUMULATING SNOW SHOULD BE ACROSS THE HIGHER
ELEVATION OF THE ADIRONDACKS AND THE TUG HILL PLATEAU...WHERE
PROBABILITIES OF 4"+ ARE HIGH...WITH ABOUT A 30% CHANCE OR SO OF
APPROACHING 8" OVER THE NEXT 72 HOURS. ALSO COULD SEE A SWATH OF
1-4" NORTHEAST OF LAKE ERIE.


...SOUTHERN ROCKIES/SOUTHERN PLAINS...

A DEEPENING TROUGH OVER THE SOUTHWEST ON FRIDAY WILL RESULT IN AN
INCREASING PRECIPITATION SHIELD ACROSS PORTIONS OF NEW MEXICO INTO
TEXAS FRIDAY INTO SATURDAY. MOST OF THIS WILL BE IN THE FORM OF
RAIN...ALTHOUGH COLD AIR WORKING IN FROM THE NORTH WILL ATTEMPT TO
CHANGE PRECIPITATION TO SNOW FROM PORTIONS OF THE OKLAHOMA AND
TEXAS PANHANDLE INTO EASTERN NEW MEXICO. STILL UNCERTAINTY WITH
REGARDS TO THE TIMING/MAGNITUDE OF THE COLD AIR AND HOW THIS MAY
OR MAY NOT OVERLAP WITH FALLING PRECIPITATION. ALTHOUGH RECENT
TRENDS APPEAR TO BE IN THE DIRECTION OF FAVORING AT LEAST SOME
LIGHT SNOW ACCUMULATION POTENTIAL OVER THE AFOREMENTIONED AREA.
THE ECMWF/GEM REMAIN A BIT SNOWIER THAN THE GFS/NAM...ALTHOUGH
EVEN THE GFS/NAM HAVE TRENDED TOWARDS A BIT MORE SNOW. FOR NOW WPC
FAVORS SOMETHING CLOSE TO A MODEL CONSENSUS FOR THIS SYSTEM. THIS
SUGGESTS A 1-3" SNOWFALL FOR PORTIONS OF THE TX/OK
PANHANDLE...WITH CLOSER TO 3-6" ACROSS PORTIONS OF EASTERN NM. OUR
MANUALLY ADJUSTED MULTI MODEL ENSEMBLE SHOWS A 50-70% OF 2"+ FROM
THE OK/TX PANHANDLE INTO EASTERN NM...WITH 4" PROBS OF 20-40%
ACROSS THE TX/OK PANHANDLE AND AS HIGH AS 60% OVER PORTIONS OF
EASTERN NM. TEMPERATURE PROFILES WILL BE MARGINAL SO WILL HAVE
CONTINUE TO MONITOR...BUT THE THREAT OF A LIGHT ACCUMULATING SNOW
DOES APPEAR TO BE INCREASING ACROSS THIS AREA FRIDAY NIGHT INTO
SATURDAY.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

CHENARD

$$




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