Quantitative Precipitation Forecast
Issued by NWS

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
000
FOUS11 KWBC 260809
QPFHSD

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
408 AM EDT TUE APR 26 2016

VALID 12Z TUE APR 26 2016 - 12Z FRI APR 29 2016

DAYS 1-3...

...CENTRAL GREAT BASIN TO THE CENTRAL/NORTHERN ROCKIES AND
ADJACENT HIGH PLAINS...

AN ACTIVE PATTERN ACROSS THE WESTERN HALF OF THE NATION WILL ALLOW
LATE SEASON SNOWFALL TO CONTINUE FOR PORTIONS OF THE CENTRAL GREAT
BASIN AND CENTRAL/NORTHERN ROCKIES THROUGH THE MIDDLE OF THE WEEK.


THE INITIAL FOCUS FOR SNOW WILL BE WITH AN ANOMALOUS CLOSED
LOW/UPPER TROUGH CROSSING THE ROCKIES AND PIVOTING OUT INTO THE
HIGH PLAINS ON TUESDAY.  THE GREATEST CHANCE FOR HEAVY
ACCUMULATIONS WILL BE ACROSS THE LARAMIE...BIG HORN...AND WIND
RIVER MOUNTAINS IN WYOMING...WHERE DIVERGENCE WITHIN THE LEFT-EXIT
REGION OF AN UPPER JET WILL COMBINE WITH LOW LEVEL CONVERGENCE AND
OROGRAPHIC LIFT.  WHILE THE UPPER TROUGH LIFTS THROUGH THE GREAT
PLAINS ON WEDNESDAY...SNOW WILL BE POSSIBLE WITHIN THE NORTHERN
EXTENT OF PRECIPITATION DEVELOPING ALONG AN INVERTED SURFACE
TROUGH EXTENDING NORTHWESTWARD FROM AN ASSOCIATED SURFACE LOW
TRACKING OUT OF THE CENTRAL PLAINS.  HOWEVER...THE POTENTIAL FOR
ANY ACCUMULATIONS REMAINS VERY UNCERTAIN.

BEFORE SNOW COMES TO AN END WITH THE INITIAL CLOSED LOW/UPPER
TROUGH EXITING THE ROCKIES ON WEDNESDAY...YET ANOTHER UPPER TROUGH
WILL BEGIN AMPLIFYING OVER THE WESTERN U.S..  THIS SYSTEM IS
EXPECTED TO TRACK SLIGHTLY FURTHER SOUTH THAN THE FIRST...WHICH
SHOULD BRING THE GREATEST THREAT FOR HEAVY SNOW INTO THE COLORADO
ROCKIES ON THURSDAY.

UNCERTAINTY STILL EXISTS WITH THE EXACT EVOLUTION OF THE INITIAL
UPPER TROUGH LIFTING OUT INTO THE GREAT PLAINS...SO A MULTI-MODEL
BLEND WAS USED TO ACCOUNT FOR THE RESULTING LARGE DIFFERENCES IN
SNOWFALL ACCUMULATION LOCATIONS AND AMOUNTS ACROSS THE NORTHERN
HIGH PLAINS ON WEDNESDAY.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.


...NORTHEAST...

SNOW IS EXPECTED WITHIN THE NORTHERN EDGE OF WARM ADVECTION
PRECIPITATION DEVELOPING OVER THE NORTHEAST ON TUESDAY.  ENHANCED
SNOWFALL RATES WITHIN AN AREA OF DIVERGENT FLOW ALOFT COULD ALLOW
FOR SNOW TO ACCUMULATE...ESPECIALLY OVER THE HIGHER ELEVATIONS OF
THE ADIRONDACKS AND PORTIONS OF THE GREEN AND WHITE MOUNTAINS.
MODEL GUIDANCE REMAINED IN VERY GOOD AGREEMENT WITH THE POTENTIAL
AXIS OF ACCUMULATING SNOW ACROSS THE REGION.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.


GERHARDT

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.