Quantitative Precipitation Forecast
Issued by NWS

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FOUS11 KWBC 160639
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 AM EDT THU APR 16 2015

VALID 12Z THU APR 16 2015 - 12Z SUN APR 19 2015

...CENTRAL ROCKIES...

00Z GUIDANCE SHOWS GOOD CONSISTENCY WITH THE PREVIOUS
FORECAST...STILL DEPICTING A VERY HEAVY SNOW EVENT FOR THE HIGHER
ELEVATIONS OF THE CENTRAL ROCKIES FOR TODAY THROUGH FRIDAY BEFORE
WINDING DOWN.  1 TO 2 FEET OF SNOW IS EXPECTED AT ELEVATIONS ABOVE
6000 FEET.  THE MAIN ADJUSTMENTS TO THE FORECAST WERE TO
INCORPORATE A SLIGHT SOUTHWARD TREND IN THE SNOW OVER THE NEXT 24
HOURS...PER 700 MB FLOW TRENDS...AND A NORTHWARD TREND FOR
THURSDAY INTO FRIDAY...ALSO PER 700 MB MB FLOW TRENDS...THE LATTER
TREND ASSOCIATED WITH THE SHORTWAVE TROUGH CROSSING THE NORTHERN
ROCKIES SATURDAY NIGHT...THUS HELPING TO EJECT THE LOW OUT OF THE
REGION.  THE FINAL PROBABILITIES ARE WEIGHTED TOWARD AN
INTERMEDIATE SNOWFALL INVOLVING THE PREVIOUS FORECAST WITH THE 00Z
NAM/GFS...WHICH PRODUCE LOW TO MODERATE PROBABILITIES OF 12 INCHES
OR MORE IN 24 HOURS AT ELEVATIONS ABOVE 8000 FT NORTHWEST OF
DENVER...AS WELL AS THE HIGHEST PEAKS OF THE WASATCH...AND ACROSS
PORTIONS OF THE LARAMIE MOUNTAINS.  SURROUNDING THE PROBABILITIES
OF 12 INCHES OF SNOW ARE CLOSELY-SPACED PROBABILITIES OF 4 AND 8
INCHES OF SNOW...WITH THE FOOTHILLS RECEIVING LITTLE TO NO SNOW.
PLEASE REFER TO THE LOCAL WFO`S FOR ALL WINTER WEATHER HEADLINES.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

...MAINE...

THE SURFACE LOW AND COLD FRONT POSSIBLY CROSSING MAINE ON SATURDAY
MAY BE ACCOMPANIED BY SUFFICIENTLY COLD AIR AND LIQUID EQUIVALENT
TOTALS TO SUPPORT A LOW PROBABILITY OF 4 INCHES OF SNOW FOR
NORTHERN MAINE...WITH AN INTERMEDIATE SOLUTION INVOLVING THE 00Z
GFS AND 12Z ECMWF PREFERRED TO ADDRESS THE SPREAD AND CREATE THE
PROBABILITIES.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

JAMES


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