Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5
000
FXUS02 KWBC 180453
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1253 AM EDT THU SEP 18 2014

VALID 12Z SUN SEP 21 2014 - 12Z THU SEP 25 2014


THE GLOBAL NUMERICAL MODELS ARE INDICATING A PATTERN CHANGE ACROSS
THE UNITED STATES LATE IN THE MEDIUM RANGE VIA A POWERFUL JET
PUNCHING INTO THE PACIFIC NORTHWEST. THE BLOCKINESS OVER THE
NATION EARLY IN THE FORECAST--AS WELL AS THE TENACIOUS POLAR
STREAM ASTRIDE THE CANADIAN BORDER--SHOULD BE WIPED AWAY WITHIN A
WEEK. AS WITH ANY SIGNIFICANT PATTERN CHANGE, THE MODEL SOLUTIONS
ARE MARKED BY IMPORTANT DIVERGENCE--PARTICULARLY OVER THE
NORTHEASTERN PACIFIC OCEAN WHENCE THE IMPETUS FOR THE SHUFFLING
EMERGES. FORTUNATELY, THE MOST RECENT ECENS AND NAEFS MEANS ARE
CORRELATED WELL ENOUGH TO PROVIDE A STABLE SYNOPTIC BASE FROM
WHICH TO BUILD THE CURRENT FORECAST. WHILE THERE IS STILL A THREAT
FOR HEAVY RAINFALL FROM THE REMNANTS OF TROPICAL CYCLONE ODILE
OVER THE SOUTHERN PLAINS, THE FRESH INFLUX OF ENERGY INTO THE
NORTHWEST SHOULD THWART ANY PROTRACTED LINGERING OF THE VORTICITY
AND ASSOCIATED DEEP-LAYER MOISTURE. THE MOST DRAMATIC SENSIBLE
WEATHER SHIFT WILL BE IN THE NORTHWEST, WITH THE CASCADES, COASTAL
RANGES, AND IMMEDIATE PACIFIC COAST BEARING THE BRUNT.



CISCO

$$





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