Quantitative Precipitation Forecast
Issued by NWS

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FOUS11 KWBC 272017
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
416 PM EDT WED APR 27 2016

VALID 00Z THU APR 28 2016 - 00Z SUN MAY 01 2016

DAYS 1-3...

...NORTHERN PLAINS...

SNOW WILL CONTINUE OVERNIGHT AND INTO THURSDAY MORNING ACROSS
PORTIONS OF THE NORTHERN PLAINS WITH MOISTURE WRAPPING WESTWARD
AROUND THE SURFACE LOW OVER THE CENTRAL PLAINS. LOW LEVEL
FRONTOGENETICAL FORCING WILL WANE RATHER QUICKLY AS THE SURFACE
LOW PULLS AWAY FROM THE REGION LEADING TO A DECREASE IN COVERAGE
AND INTENSITY OF PRECIPITATION. THE ECMWF WAS AN OUTLIER BEING A
LITTLE MORE AGGRESSIVE WITH THE QPF AND COLDER IN THE BOUNDARY
LAYER LEADING TO MORE SNOWFALL. GIVEN THE LOCALLY HEAVY SNOWFALL
OBSERVED TODAY IT DEFINITELY REMAINS A POSSIBILITY TO SEE SOME
HIGHER AMOUNTS BUT THE REST OF THE MODEL GUIDANCE WAS WELL
CLUSTERED AND CONSISTENT WITH AMOUNTS IN THE 1 TO 4 INCH RANGE.
WPC FORECAST WAS BASED ON A MULTI MODEL BLEND.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.


...CENTRAL GREAT BASIN/ROCKIES...

LATE SEASON SNOWFALL IS EXPECTED ACROSS THE HIGHER ELEVATIONS OF
THE CENTRAL GREAT BASIN AND ROCKIES THROUGH THE END OF THE WEEK AS
CONSECUTIVE STORM SYSTEMS CONTINUE TO PROGRESS INLAND OVER THE
WESTERN U.S...ONE PIVOTING OUT INTO THE GREAT PLAINS ON
WEDNESDAY...A SECOND EDGING OUT OF THE SOUTHWEST ON THURSDAY...AND
FINALLY A THIRD DIGGING SOUTHWARD THROUGH THE PACIFIC NORTHWEST ON
FRIDAY.

THE HEAVIEST AND MOST WIDESPREAD SNOWFALL SHOULD BE WITH THE
SECOND SYSTEM EDGING EASTWARD OUT OF THE SOUTHWEST.  ESPECIALLY
ACROSS THE COLORADO ROCKIES...WHERE THE COMBINATION OF STRONG
UPPER DIVERGENCE WITHIN THE LEFT EXIT REGION OF AN UPPER JET AND
INCREASINGLY MOIST LOW-LEVEL FLOW INTO THE TERRAIN WILL HELP
ENHANCE SNOWFALL RATES THURSDAY AND FRIDAY.

MODEL GUIDANCE WAS IN REASONABLE AGREEMENT WITH DEPICTING SNOWFALL
ACROSS THE HIGHER ELEVATIONS...BUT THERE WERE LARGE DISCREPANCIES
WITH THE POTENTIAL FOR ANY ACCUMULATING SNOW SPREADING OUT INTO
THE CENTRAL HIGH PLAINS AS THE SECOND SYSTEM LIFTS OUT OF THE
ROCKIES FRIDAY NIGHT. THE GFS INCREASINGLY BECOMES A SLOWER AND
WARMER OUTLIER BY SATURDAY AS THE SURFACE LOW MOVES INTO THE
PLAINS. WITH THAT IN MIND...DAY 3 FORECAST LEANS MORE TOWARD THE
NAM/ECMWF CAMP AND THEIR RESPECTIVE ENSEMBLE MEANS.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.


KREKELER/GERHARDT

$$





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