Prognostic Meteorological Discussion
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FXAK02 KWNH 281817
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
217 PM EDT FRI AUG 28 2015

VALID 12Z TUE SEP 01 2015 - 12Z SAT SEP 05 2015

THE 28/00Z ECENS/GEFS WERE IN RATHER GOOD AGREEMENT WITH HAS
BECOME A RATHER FASCINATING PATTERN IN THE PACIFIC. THE REMNANT
CIRCULATION ASSOCIATED WITH `ATSANI` HAS ABSORBED AND EJECTED
`LOKE`. AND `GONI` IS NOW A CLOSED MID-LATITUDE --- AND NEARLY
STATIONARY --- CYCLONE IN EXTREME NORTHEAST CHINA.

WHAT REMAINS OF `ATSANI` APPEARS TO BE TAKING ON THE APPEARANCE OF
A `NEGATIVE-TILT TROUGH` AND THERE IS A CLEAR NORTHERN STREAM FLOW
AND CONNECTION OVER THE HIGH ARCTIC (NE SIBERIA)---WITH THE
PACIFIC NORTHWEST COAST OF THE MAINLAND.

IF THIS WERE JANUARY---BUT IT`S NOT. AND WITH THREE TROPICALS
(SOUTH OF 20N) AND A NEW `CUTOFF` LOW INVOF 30N 170W REPLACING THE
`OLD ONE`....THE CENTRAL PACIFIC IS BEGINNING TO TAKE ON THE `VERY
BLOCKY` LOOK IT DID 10-15 DAYS AGO.

THE PLACEHOLDER---FOR MUCH OF THE MEDIUM RANGE PERIOD HAS BEEN AND
SHOULD CONTINUE TO BE--- THE CIRCULATION FORMALLY KNOWN AS
`ATSANI`. ITS LOCATION NEAR 40N 170E SERVES TO CYCLE SUBTROPICAL
MOISTURE NORTHWARD FROM NORTHWEST OF HAWAI`I DOWNSTREAM INTO THE
`CONFLUENCE` ESTABLISHED BY THE NORTHERN STREAM FLOW PATTERN.

WHERE THERE IS A DETERMINISTIC DIFFERENCE---IT CONCERNS TROPICAL
TO MID-LATITUDE ENERGY TRANSFER ---BETWEEN 170E AND 170W. AND A
VERY GRADUAL EASTWARD MIGRATION OF THE `TRANSFER` ZONE AND `BLOCKY
PATTERN` THIS MEDIUM RANGE PERIOD. AND `KILO` IS `THE HEART` OF
ALL THE MID-PACIFIC BASIN MODEL SPREAD AMONGST THE 28/00Z
GUIDANCE.

FOR ALASKA...GENERALLY A PERSISTENCE-TYPE FORECAST...WITH THE GULF
OF ALASKA IN A BROAD NORTHWEST (COLD ADVECTION) REGIME THAT DOES
LOOK MORE LIKE THE COOL/COLD SEASON.

AS A SIDE NOTE---NOT SURE WHY THE GRIDDED SOLUTION FROM 24 HOURS
AGO HAD SO LOW OF A POP `LOOK`---PRETTY MUCH THROUGH THE ENTIRE
MEDIUM RANGE PERIOD. THAT SEEMS TO HAVE `CORRECTED` ITSELF TODAY.

VOJTESAK






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