Prognostic Meteorological Discussion
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FXUS02 KWBC 250718
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
217 AM EST SUN JAN 25 2015

VALID 12Z WED JAN 28 2015 - 12Z SUN FEB 01 2015

...AN ACTIVE WINTER PATTERN FOR THE COMING WEEK...

...GUIDANCE AND UNCERTAINTY ASSESSMENT...

THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
COMPOSITE BLEND OF THE 18 UTC GFS AND 12 UTC
CANADIAN/ECMWF/UKMET/ECMWF ENSEMBLE MEAN INTO DAY4 THU. MADE A
TRANSITION TO A MUCH MORE ECMWF ENSEMBLE MEAN CENTRIC SOLUTION
DAYS 5-7 THROUGH NEXT WEEKEND IN A PATTERN WITH GROWING FORECAST
SPREAD AND UNCERTAINTY. THESE GUIDANCE COMBOS KEEP THE WPC
FORECAST LEANING THROUGH THE ENTIRE FORECAST PERIOD WITH SCENARIOS
GENERALLY ON THE SLIGHTLY MORE AMPLIFIED SIDE OF A COMPOSITE OF
THE FULL ENVELOPE OF SOLUTIONS. THIS MAINTAINS GOOD WPC CONTINUITY
BUT ALLOWS FOR RECENT OVERALL PATTERN AND RUN-RUN MODEL AND
ENSEMBLE TRENDS.

...PATTERN OVERVIEW AND SENSIBLE WEATHER HIGHLIGHTS...

THE MEDIUM RANGE PERIOD STARTS LATE WEEK WITH AN AMPLIFYING
MID-UPPER LATITUDE PATTERN AT MID-UPPER LEVELS. THIS IS
HIGHLIGHTED BY A WARMING WRN NOAM MEAN RIDGE WHOSE DEVELOPMENT
ALLOWS DEEPER DOWNSTREAM CARVING OF AN INCREASINGLY COLD AIR FED
EAST-CENTRAL NOAM MEAN TROUGH. A SERIES OF ENERGETIC EMBEDDED
IMPULSES ALOFT LEND  SURFACE BASED LOW/SYSTEM GENESIS. WPC PROGS
OFFER A TRAILING COLD FRONTAL SURGE DOWN ACROSS THE US SRN TIER IN
THE WAKE OF THE TRACK OF AN ORGANIZED WINTER PCPN FOCUSING LOW
FROM THE GREAT LAKES/MIDWEST DAY 4/THU TO THE NORTHEAST DAY 5/FRI
HOT ON THE HEELS OF A LEAD SHORT RANGE STORM...BUT WITH LESS
AVAILABLE MOISTURE. WPC PROGS THEN SHOW A FRIGID ARCTIC BLAST INTO
THE CENTRAL US BY DAY 6/SAT THAT SUBSEQUENTLY SPREADS RAPIDLY
ACROSS THE EAST DAY 7 WITH FRONTAL PASSAGE. THIS LEADS TO ANOTHER
POTENTIAL COLD LOW/WINTER PCPN THREAT POSSIBLY FROM THE
MIDWEST/GREAT LAKES BY SAT TO THE MID-ATLC/NERN US AND OFFSHORE BY
SUPERBOWL SUNDAY.

MEANWHILE AT LOWER LATITUDES...YET ANOTHER ERN PACIFIC MID-UPPER
LEVEL TROUGH WORKS SLOWLY TOWARD CA AND THE SWRN US/NW MEXICO DAYS
4-6 THU THROUGH NEXT WEEKEND. THE APPROACH WOULD ALLOW FOR
POTENTIAL FOR INCREASED LEAD MOISTURE FEED AND PCPN INTO SRN CA
AND THE SWRN US...EVENTUALLY WITH POTENTIAL TO ALSO REACH AND
/INTERACT WITH COLDER AIRMASS DELIVERY THROUGH THE SRN
ROCKIES/PLAINS. PLAN THOUGH TO PLAY-DOWN SOME OF THE MODEL AND
ENSEMBLE PCPN AMOUNTS FOR NOW GIVEN USUAL UNCERTAINTY WITH THE
NATURE/TIMING OF THESE TYPE OF CLOSED SYSTEMS.

SCHICHTEL

$$




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