Quantitative Precipitation Forecast
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
000
FOUS11 KWBC 250835
QPFHSD

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

VALID 12Z SAT APR 25 2015 - 12Z TUE APR 28 2015


DAYS 1 TO 3...

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

A RATHER UNSETTLED PERIOD CONTINUES FOR MUCH OF THE WESTERN UNITED
STATES THROUGH THE WEEKEND INTO EARLY NEXT WEEK... WHICH INCLUDES
THE THREAT FOR HEAVY MTN SNOW FOR PARTS OF THE CENTRAL TO SRN
ROCKIES.

A CLOSED MID TO UPPER LOW OVER WA WILL STEER A DYNAMIC UPPER JET
STREAK AND SHORT WAVE DYNAMICS SOUTH AND EAST THROUGH CA/NV INTO
THE DESERT SW ON SAT. FAVORABLE LARGE SCALE SWRLY UPPER DIFLUENT
FLOW ALOFT ACROSS MUCH OF THE INTER-MOUNTAIN WEST ALONG WITH LEFT
EXIT REGION DYNAMICS FOCUSED FROM CA TO THE GREAT BASIN SHOULD
FUEL WIDESPREAD MTN SNOW. THIS IS ESPECIALLY TRUE FROM THE CENTRAL
SIERRA TO THE WASATCH AND UINTAS OF UT AND INTO THE
TETONS/ABSAROKA AND WIND RIVER RANGES OF WY. WPC FOLLOWED A BLEND
OF THE GFS/ECMWF FOR 4 TO 12 INCH HEAVY SNOW PROBS.

THEN ON SUN AND MON... THE JET DYNAMICS DIGGING INTO THE SW FROM
SAT BEGIN TO CLOSE OFF A RATHER LARGE PRONOUNCED CLOSED UPPER LOW
ALONG THE SRN STREAM... WHICH WILL SLOWLY PRESS DOWNSTREAM THROUGH
THE FOUR CORNERS REGION INTO TX/OK. THUS SUN SHOULD FEATURE
INCREASING WIDESPREAD ERLY TO SERLY UPSLOPE FLOW INTO THE CENTRAL
TO SRN ROCKIES AND THE OPPORTUNE TO TAP INTO MORE AVAILABLE HIGH
MOISTURE CONTENT. THE RESULT WILL BE HEAVY SNOWFALL MORE CONFINED
TO THE HIGHER ELEVATIONS FROM THE BIG HORNS/WIND RIVER RANGES OF
WY SOUTH INTO MUCH OF THE CO ROCKIES AND SAN JUANS/SANGRE DE
CRISTO MTNS. ITS THE SRN TIER OF THE SYSTEM OF THE SANGRE DE
CRISTO OF SERN CO/NERN NM WHICH WILL BE POTENTIALLY THE HEAVIEST
SNOWFALL AND THIS CONTINUES ON MON. THE PRESSURE GRADIENT TIGHTENS
SOME TO INTENSIFY THE UPSLOPE COMPONENT... WHILE STRONG DYNAMIC
COOLING ALOFT ON THE NW QUAD OF THE LARGE CIRCULATION HELP LOWER
SNOW LEVELS AND INCREASE SNOW INTENSITY OF POSSIBLE SIGNIFICANT
ACCUMULATIONS. THOUGH THIS IS A BIT MORE UNCERTAIN DUE TO SLIGHT
MODEL SPREAD AND BECOMING MARGINAL TEMP PROFILES. OVERALL FOR THE
TWO DAYS... WP FOLLOWED A BLEND OF THE GFS/ECMWF FOR 4 TO 12 INCH
HEAVY SNOW PROBS.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.

MUSHER


$$




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