THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


PROBABILISTIC HEAVY SNOW AND ICE DISCUSSION




PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
249 AM EDT WED OCT 01 2014

VALID 12Z WED OCT 01 2014 - 12Z SAT OCT 04 2014


DAY 1...

...WYOMING AND COLORADO ROCKIES...

AN AMPLIFYING SHORT WAVE TROUGH WILL SLIDE ACROSS THE CENTRAL
ROCKIES WHILE COMBINING ENHANCED VERTICAL LIFT AND OROGRAPHY.
FREEZING LEVELS WILL FALL FROM 9000/10000 FEET TO BETWEEN 7000 AND
8000 FEET ON WEDNESDAY INTO EARLY THURSDAY WHILE SEVERAL MODELS
FORECAST QPF AMOUNTS LOCALLY IN EXCESS OF .5 INCHES ACROSS THE
CENTRAL AND NORTHERN COLORADO ROCKIES AND ACROSS THE HIGH MOUNTAIN
RANGES OF NORTHERN AND NORTHWESTERN WYOMING.  AS A RESULT...THE
HIGHEST PEAKS HAVE AT LEAST A MODERATE RISK OF 4 TO 8 INCHES OF
SNOW ON DAY 1.

DAYS 2 AND 3...

A COMPLEX SERIES OF SHORT WAVES ARE EXPECTED TO INTERACT ALTHOUGH
THE DETAILS OF THE INTERACTION ARE STILL RATHER UNCERTAIN...ON
DAYS 2 AND 3...THURSDAY THROUGH SATURDAY MORNING.  THE ONE
SOUTHERN STREAM SYSTEM ASSOCIATED WITH THE SNOW IN THE ROCKIES ON
DAY 1 IS EXPECTED TO INTERACT WITH SEPARATE UPPER JETS/TROUGHS
MIGRATING SOUTHEASTWARD FROM WESTERN CANADA AND ARE EXPECTED TO
BRING COLDER TEMPERATURES SOUTH AND EASTWARD ACROSS THE NORTHERN
ROCKIES/NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY.  WHILE
TEMPERATURES ARE EXPECTED TO BE MARGINAL FOR SNOWFALL IN THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY...THERE STILL MAY BE
THE POTENTIAL FOR SNOW ESPECIALLY ACROSS PORTIONS OF NORTH DAKOTA
AND NORTHEASTERN MINNESOTA.  RIGHT NOW THERE ARE ONLY LOW
PROBABILITIES FOR SNOWFALL EXCEEDING 4 INCHES WITH THE GREATEST
LIKELIHOOD FOR SIGNIFICANT SNOW ON FRIDAY NIGHT INTO EARLY
SATURDAY ACROSS WESTERN ONTARIO AS A SURFACE LOW IS EXPECTED TO
INTENSIFY AS IT MOVES NORTHEASTWARD ACROSS THE GREAT LAKES INTO
SOUTH CENTRAL CANADA. 

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT ON
ALL 3 DAYS.


KOCIN





Last Updated: 249 AM EDT WED OCT 01 2014