Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6
000 FXUS02 KWBC 260639 PMDEPD EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 138 AM EST MON JAN 26 2015 VALID 12Z THU JAN 29 2015 - 12Z MON FEB 02 2015 ...ACTIVE SPLIT-FLOW FOR THE LOWER 48... ...GUIDANCE AND UNCERTAINTY ASSESSMENT... THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A COMPOSITE BLEND OF THE REASONABLY COMPATABLE 18 UTC GFS AND 12 UTC ECMWF AND ECMWF/NAEFS ENSEMBLE MEANS THROUGH DAY4/FRI. SWITCHED TO AN INCREASINGLY ECMWF ENSEMBLE MEAN CENTRIC SOLUTION DAYS 5-7 IN A PATTERN WITH GROWING FORECAST SPREAD AND UNCERTAINTY. THE 12 UTC ECMWF AND NAEFS MEAN ALSO FALL IN A SIMILAR GUIDANCE CLUSTER AS THE ECMWF ENSEMBLE MEAN AND REMAIN VIABLE TO A LESSER DEGREE. WPC PREFERRED GUIDANCE LEANS THROUGH THE FORECAST PERIOD WITH FLOW EVOLUTION GENERALLY ON THE MORE AMPLIFIED SIDE OF A COMPOSITE OF THE FULL ENVELOPE OF SOLUTIONS. THIS MAINTAINS GOOD WPC CONTINUITY AND STRONGLY DOWNPLAYS QUITE DRASTICALLY DIFFERENT GUIDANCE BASED FROM 12/18 UTC GFS IN THE SAT-NEXT MON TIME FRAME. THIS IS ESPECIALLY EVIDENT WITH THE DEPTH/BREATH OF A CANADIAN AIRMASS INTRUSION AND LEAD LOW DEVELOPMENTS AND WEATHER FOCUS DOWN INTO THE LOWER 48. ...PATTERN OVERVIEW AND SENSIBLE WEATHER HIGHLIGHTS... THE MEDIUM RANGE PERIOD STARTS LATE WEEK WITH AN AMPLIFYING NRN STREAM MID-UPPER LATITUDE PATTERN AT MID-UPPER LEVELS. THIS IS HIGHLIGHTED BY A WARMING WRN NOAM MEAN RIDGE WHOSE DEVELOPMENT SHOULD ALLOW DEEP 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 3/WED TO THE NORTHEAST DAY 4/FRI ON THE HEELS OF A MAJOR LEAD SHORT RANGE STORM...BUT WITH LESS AVAILABLE MOISTURE. WPC PROGS THEN SHOW A MORE FRIGID ARCTIC BLAST INTO THE CENTRAL US BY DAY 5/SAT THAT SUBSEQUENTLY SPREADS RAPIDLY SOUTHWARD AND OUT ACROSS THE ERN US DAY 6/SUN WITH WAVY FRONTAL PASSAGE. THIS LEADS TO ANOTHER POTENTIAL COLD LOW/WINTER PCPN THREAT POSSIBLY FROM THE N-CENTRAL STATES AND MIDWEST/GREAT LAKES BY SAT TO THE MID-ATLANTIC AND ESPECIALLY THE NERN US THEN OFFSHORE SUPERBOWL SUNDAY. MEANWHILE AT LOWER LATITUDES...AN ERN PACIFIC MID-UPPER LEVEL TROUGH NEARS CA/SWRN US/NW MEXICO LATE WEEK PAST NEXT WEEKEND. THE WOULD ALLOW FOR POTENTIAL FOR INCREASED SRN STREAM IMPULSE AND LEAD MOISTURE FEED/PCPN INTO SRN CA/SWRN US AND DOWNSTREAM TO INTERACT WITH COLDER AIRMASS DELIVERY THROUGH THE SRN ROCKIES/NRN MEXICO TO OVERRUN THE S-CENTRAL US. PLAN TO PLAY-DOWN HEAVIER MODEL/ENSEMBLE QPFS AND TO A LESSER EXTENT POPS FROM THE HIGH FREQUENCY FROM ECMWF ENSEMBLES GIVEN UNCERTAINTY WITH THE NATURE/TIMING OF THESE TYPE OF SYSTEMS. SCHICHTEL $$

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