Quantitative Precipitation Forecast
Issued by NWS

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FOUS11 KWBC 190910
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
409 AM EST WED NOV 19 2014

VALID 12Z WED NOV 19 2014 - 12Z SAT NOV 22 2014

DAYS 1 THROUGH 3...

...GREAT LAKES...
HEAVY LAKE EFFECT SNOWS WILL LINGER OVER THE NEXT FEW DAYS BUT
NOWHERE ON THE SCALE OF THE PAST 24 HRS. HOWEVER ON THURS... THE
POTENTIAL EXISTS FOR ANOTHER ROUND OF LONG FETCH BANDS COMING OFF
OF BOTH LAKE ERIE AND ONTARIO INTO PARTS OF WRN AND UPSTATE NY.

SURFACE AND SHORT WAVE RIDGING AT 700MB IS BUILDING IN ACROSS THE
LAKES IN ADVANCE OF ANOTHER STRONG POLAR/ARCTIC RE-ENFORCING SHORT
WAVE TROUGH. THIS WILL RESULT IN A WAVE OF LOW PRESSURE AND
SURFACE WARM FRONT TO PROGRESS THROUGH THE LAKES TO TRIGGER WARM
ADVECTION AND LAKE ENHANCED SNOWS ACROSS MI ON WED. AS THE SYSTEM
ADVANCES DOWNSTREAM ON LATE WED INTO THURS... THE COLD ANOMALOUS
AIR MASS INTERACTING WITH THE WARM LAKES WILL IGNITE ANOTHER
PERIOD OF NON-SHEAR UNIFORM FLOW ACROSS PARTS OF THE LAKES. THIS
WILL RESULT IN SEVERAL MESOSCALE HEAVY LAKE EFFECT SNOW BANDS WITH
THE MOST OPPORTUNE AREAS BEING PARTS OF THE UP OF MI AND ONCE
AGAIN PARTS OF SWRN NY STATE... JUST SOUTH OF BUF... AND INTO
UPSTATE NY. ITS THE LATTER TWO WITH THE HISTORY FROM TUES AND
ALMOST SEMI-IDENTICAL SETUP THAT COULD RESULT IN QUITE IMPRESSIVE
SNOW TOTALS. OVERALL WPC STAYED VERY CLOSE TO THE HI RES NAM AND
ECMWF WITH HELP FROM THE SREF MEAN FOR HEAVY SNOW PROBS ON WED AND
THURS.


...PACIFIC NORTHWEST INTO NORTHERN ROCKIES...

ON FRI INTO SAT... RATHER MOIST ZONAL FLOW OVER THE PAC WILL REACH
THE PAC NW INTO THE NRN ROCKIES. A CLOSED UPPER VORTEX FORMING
NEAR THE ALEUTIAN CHAIN WILL DIRECT AN ACTIVE UPPER JET AND
SPECIFIC JET STREAK INTO THE REGION TO CRASH UPPER HEIGHTS AND
TRANSPORT A WEALTH OF PAC MOISTURE. THIS SHOULD RESULT IN IDEAL
OROGRAPHICS AND STEADY LOWERING OF SNOW LEVELS FROM THE WA/OR
CASCADES INTO THE INTERIOR NRN BITTERROOTS AND
BLUE/SAWTOOTH/SALMON MTNS. WPC GENERALLY FOLLOWED A BLEND OF THE
GLOBAL MODELS OR GFS/ECMWF ON THE HANDLING OF THIS PATTERN CHANGE
AND SYSTEM ARRIVING INTO THE REGION ALONG WITH THE HEAVY SNOW
PROBS.


THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

MUSHER

$$




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