Quantitative Precipitation Forecast
Issued by NWS

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450
FOUS11 KWBC 282134
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
434 PM EST MON NOV 28 2016

VALID 00Z TUE NOV 29 2016 - 00Z FRI DEC 02 2016

DAY 1 TO 3...

...PACIFIC NORTHWEST/ROCKIES...

WIDESPREAD OROGRAPHICALLY ENHANCED SNOW SHOWERS WILL CONTINUE
ACROSS THE CASCADES AND ROCKIES MONDAY NIGHT...BENEATH SHORTWAVE
ENERGY DIGGING INTO WESTERN EDGE OF AN EXPANSIVE TROUGH CARVED OUT
OVER THE U.S..  ACTIVITY SHOULD DECREASE ON TUESDAY AS THE TROUGH
AXIS SHIFTS EAST AND RIDGING BRIEFLY BUILDS IN ALOFT...BUT THEN
ADDITIONAL PERIODS OF HEAVY SNOW WILL BE POSSIBLE ACROSS THE
HIGHER ELEVATIONS OF THE CASCADES AND NORTHERN ROCKIES BY EARLY
WEDNESDAY AS SNOW LEVELS DROP AND MOISTURE INCREASES WITH THE NEXT
SHORTWAVE APPROACHING THE NORTHWEST.


...NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY...

MODERATE TO HEAVY SNOW ACROSS THE NORTHERN PLAINS SHOULD BEGIN TO
DECREASE IN INTENSITY MONDAY NIGHT AS AN ANOMALOUS UPPER LOW AND
DEEP SURFACE CYCLONE GRADUALLY WEAKEN OVER THE REGION.
HOWEVER...THE UPPER LOW AND SURFACE LOW WILL BE SLOW TO EXIT
EASTWARD...KEEPING ACCUMULATING SNOW POSSIBLE ACROSS THE DAKOTAS
AND PORTIONS OF THE UPPER MISSISSIPPI VALLEY THROUGH WEDNESDAY.



...MAINE/INTERIOR NEW ENGLAND...

AN ANOMALOUS UPPER LOW OVER THE CENTRAL PORTION OF THE COUNTRY
WILL HELP STEER A COUPLE OF DYNAMIC SHORTWAVES TOWARDS THE
NORTHEASTERN CORNER OF THE NATION TUESDAY AND WEDNESDAY...ONE
SHORTWAVE CURRENTLY CROSSING THE SOUTHERN PLAINS AND A SECOND
DIGGING SOUTHEASTWARD THROUGH THE ROCKIES.  A WAVE OF DEEP
MOISTURE CONTENT WILL SURGE INTO THE NORTHEAST WITH EACH
SYSTEM...WHILE A SURFACE RIDGE TO THE NORTH WEDGES INTO THE REGION
AND UNDERCUTS THE MOIST 850MB SOUTHWESTERLY FLOW.  A VARIETY OF
PRECIPITATION TYPES ARE EXPECTED ACROSS THE REGION...FROM SOME
ICING ACROSS INTERIOR NEW ENGLAND TO HEAVY SNOW FOR NORTHERN
MAINE.  MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THE LARGE
SCALE EVOLUTION OF THE SHORTWAVES...BUT THERE ARE SUBTLE
DIFFERENCES WITH THE TIMING AND STRENGTH OF CONSECUTIVE SURFACE
LOWS DEEPENING OFF THE NEW ENGLAND COAST...LEADING TO SOME SPREAD
AND UNCERTAINTY WITH EXACT PRECIPITATION TYPE AND SNOW/ICE
ACCUMULATIONS.


THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.


GERHARDT

$$





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