Prognostic Meteorological Discussion
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FXAK02 KWNH 011853
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 PM EDT WED OCT 01 2014

VALID 12Z SUN OCT 05 2014 - 12Z THU OCT 09 2014

THE 1/00Z ECENS MEAN AND 1/06Z GEFS GENERALLY AGREE WITH RESPECT
TO LATITUDE AND LONGITUDE OF AN UPPER-LEVEL CYCLONE THROUGH DAY
5...BUT DEPART SIGNIFICANTLY WITH THE DETAILS OF INDIVIDUAL
SHORTWAVES/STORM TRACKS OF THE MORE SIGNIFICANT SURFACE
CYCLOGENESIS AREAS ALONG 50N LATITUDE BEYOND DAY 5. WAS ABLE TO
DECIPHER SOME OF THE SMALLER-SCALE SURFACE DETAILS FOR DAYS 4-5
USING THE GFS/ECMWF DETERMINISTIC GUIDANCE.

IF THERE HAS A BEEN A TREND...IT APPEARED TO BE ACROSS THE
ALEUTIANS...AND TO SHIFT THE `AVERAGED` STORM TRACK TO THE SOUTH
AND SOUTHEAST OF THE CENTRAL ALEUTIANS. THE SUBTLE SOUTHEASTWARD
SHIFT IN STORM TRACK RESULTING IN A REBUILDING OF A `MEAN`
UPPER-LEVEL RIDGE ACROSS BC...THE YUKON AND NORTH CENTRAL ALASKA.

AS MENTIONED YESTERDAY...THE MEDIUM RANGE FORECAST CONTINUES TO BE
IN FLUX...WITH A VERY LARGE SPREAD DOWNSTREAM OF THE DATELINE
ALONG 45N-50N LATITUDE AS THE UPPER-LEVEL COLD CORE TROUGH
MIGRATES ACROSS THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS. THE
COMPLEXITY OF THE FORECAST LIES IN THE POSSIBLE PHASING OF
TROPICAL DISTURBANCES ALONG THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE WITH THE EMERGING MID-LATITUDE JET STREAM
PATTERN OFF THE EAST ASIAN COAST INVOF JAPAN. FORECASTER
CONFIDENCE REMAINS LOW.

VOJTESAK

$$





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