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Winter Weather Forecast Discussion
 
(Caution: Version displayed is not the latest version. - Issued 2003Z Apr 25, 2015)
 
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Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
403 PM EDT SAT APR 25 2015

VALID 00Z SUN APR 26 2015 - 00Z WED APR 29 2015


DAYS 1 AND 2...

...PACIFIC NORTHWEST/CENTRAL GREAT BASIN/CENTRAL AND SOUTHERN
ROCKIES...

AN ON-GOING PERIOD OF UNSETTLED PERIOD OF WEATHER WILL LINGER OVER
PARTS OF THE WESTERN UNITED STATE INTO EARLY NEXT WEEK...INCLUDING
THE THREAT FOR HEAVY MTN SNOW FOR PARTS OF THE CENTRAL TO SRN
ROCKIES.

WHAT STARTS OUT AS A CLOSED MID/UPPER LOW OVER THE PAC NW WILL
SLIDE SOUTHEAST INTO THE GREAT BASIN AND DESERT SOUTHWEST BY
SUNDAY MORNING.  THERE IS MODEL AGREEMENT THAT A MID/UPPER LOW
WILL BE CROSSING THE ROCKIES FRONT RANGE BY EARLY MONDAY.  AT THAT
POINT...SOUTHEASTERLY UPSLOPE FLOW AT LOW LEVELS SHOULD BE
INCREASING OVER PARTS OF CO AND FAR NORTHERN NM IN RESPONSE TO LEE
CYCLOGENESIS OVER THE PLAINS.  DEEP LAYERED LIFT WILL BE SUPPORTED
BY STRONG UPPER LEVEL DIFLUENCE TO THE EAST OF THE MID/UPPER LEVEL
SYSTEM.  ALL OF THIS SPELLS A GOOD BET FOR MDT TO HEAVY SNOWFALL
FROM SUNDAY NIGHT INTO MONDAY IN THE CENTRAL AND SOUTHERN ROCKIES.

MOST OF THE SNOW SHOULD BE CONFINED TO THE HIGHER ELEVATIONS OF
THE MOUNTAINS WITH SOME SNOW MAKING ITS WAY OUT INTO THE
FOOTHILLS.  OF SOME NOTE...THOUGH...WAS THAT THE SPREAD IN THE
MODEL THERMAL FIELDS REMAINED FAIRLY LARGE.  THUS WE DID NOT PUT A
GREAT DEAL OF FAITH IN THE WAY THE 12Z MODEL CYCLES WENT SOMEWHAT
COOLER COMPARED WITH THE 25/00Z MODELS.  THE BEST SIGNAL IS FOR
THE HEAVIEST SNOW REMAINED CONFINED TO ELEVATIONS GENERALLY ABOVE
5500 FT OR 6000 FT ACROSS SOUTHEAST CO.

EVENTUALLY THE SYSTEM WILL PULL AWAY FROM THE ROCKIES ON MONDAY
WITH A CORRESPONDING DECREASE IN SNOWFALL INTENSITY AND AREAL
COVERAGE OF SNOWFALL. 

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

DAY 3...

THE PROBABILITY OF SIGNIFICANT SNOW AND/OR ICING IS LESS THAN 10
PERCENT.

BANN