Quantitative Precipitation Forecast
Issued by NWS

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000
FOUS11 KWBC 192102
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
501 PM EDT THU APR 19 2018

VALID 00Z FRI APR 20 2018 - 00Z MON APR 23 2018


DAYS 1-3...

...GREAT BASIN/FOUR CORNERS AND CENTRAL TO SOUTHERN ROCKIES...

A STRONG CLOSED MID TO UPPER LOW, CENTERED NEAR SOUTHERN NV THIS
AFTERNOON, WILL DELIVER SNOW TO PARTS OF THE FOUR CORNERS REGION
ON FRI AND SAT. THE GLOBAL MODELS AND ENSEMBLES CAPTURE THIS
FEATURE RATHER WELL WITH OVERALL MINIMAL SPREAD, ESPECIALLY
CONCERNING THE PROGRESSION OF THIS LARGE SCALE FEATURE. THE SYSTEM
WILL THEN SLOWLY PROGRESS INTO THE FOUR CORNERS REGION ON FRI AND
THROUGH THE CENTRAL/SOUTHERN ROCKIES INTO THE CENTRAL/SOUTHERN
PLAINS SAT. ON FRI, THE LARGE CLOSED 500 MB CIRCULATION WILL YIELD
SOME DYNAMICALLY DRIVEN AND UPSLOPE SNOWFALL FROM THE SOUTHERN
WASATCH INTO THE CO ROCKIES, ESPECIALLY FOR THE SWRN SAN JUANS OF
CO. THEN ON SAT, ENHANCED VERTICAL LIFT FROM THE PASSING MID-LEVEL
LOW AND STEADY UPSLOPE FLOW SHOULD CONTINUE TO PRODUCE HEAVY SNOW
ACROSS CO TERRAIN AND PERHAPS SPREAD TO THE PALMER DIVIDE AND
CHEYENNE RIDGE. THIS IS WHERE PTYPE ISSUES BEGIN TO EMERGE, AS A
NUMBER OF SOLUTIONS ALLOW SNOW TO SPREAD DOWN THE FOOTHILLS AND
LEE SIDE OF THE CENTRAL ROCKIES. WPC STAYED CLOSER TO THE ECMWF
THAN ANYTHING ELSE, WITH MASS FIELDS AND THERMALS.


FOR DAYS 1-3...THE PROBABILITY OF ICING GREATER THAN 0.25 INCHES
IS LESS THAN 10 PERCENT.

MUSHER



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