Prognostic Meteorological Discussion
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FXAK02 KWNH 282008
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
407 PM EDT SAT MAY 28 2016

VALID 12Z WED JUN 01 2016 - 12Z SUN JUN 05 2016

THE PATTERN TO BEGIN THE MONTH OF JUNE WILL BE BLOCKY IN NATURE AS
A PERSISTENT CLOSED UPPER HIGH WILL LINGER IN THE VICINITY OF
SIBERIA THROUGHOUT THE MEDIUM RANGE PERIOD. UNDERNEATH THIS
STAGNANT RIDGING...BROAD CYCLONIC FLOW SHOULD REMAIN IN PLAY WITH
A MYRIAD OF CIRCULATIONS PREVAILING FROM THE BERING SEA ACROSS THE
ALEUTIANS AND INTO THE GULF OF AK. MEANWHILE...TO THE EAST OF THE
RIDGE...MODELS CONTINUE TO SHOW A NEGATIVE ANOMALY SINKING DOWN
FROM THE NORTH POLE POSSIBLY GRAZING NORTHERN SECTIONS OF AK. THIS
PARTICULAR FORECAST REGIME APPEARS TO REMAIN IN PLACE THROUGH THE
END OF THE FORECAST AS THE BLOCKING RIDGE CONTINUES TO ROAM OVER
THE HIGHER LATITUDES.

WHILE THE GUIDANCE SHOWS REASONABLE AGREEMENT ACROSS THE FORECAST
DOMAIN...THERE ARE UNCERTAINTIES WITH THE PLACEMENT OF INDIVIDUAL
FEATURES. IN PARTICULAR...THE 12Z GFS/GEFS AND PREVIOUS CYCLES ARE
MORE IN LINE WITH THE 00Z CMC/NAEFS MEAN SOLUTIONS WHICH FAVOR
KEEPING THE RIDGE FARTHER NORTH WHILE ALLOWING A MORE ELONGATED
TROUGH AXIS TO EXTEND OUT TOWARD THE WESTERN ALEUTIANS. ON THE
OTHER HAND...THE 00Z ECMWF/ECMWF ENSEMBLE MEAN CONTINUE TO
INDICATE A BROAD RIDGE WHICH IS MORE SOUTHWARD DISPLACED AND MORE
EXTENSIVE IN NATURE. THIS ULTIMATELY FORCES THE PERSISTENT
NEGATIVE ANOMALY FARTHER DOWNSTREAM TOWARD THE GULF OF
AK/NORTHEASTERN PACIFIC.

THE WPC PREFERENCE LEANED MORE IN THE DIRECTION OF THE FIRST CAMP
WHICH WAS COORDINATED WITH THE ANCHORAGE FIELD OFFICE AND REMAINED
CONSISTENT WITH THE PREVIOUS SET OF PRODUCTS. FOUND ENOUGH
CLUSTERING TO UTILIZE A MULTI-DETERMINISTIC MODEL BLEND THROUGH
DAY 5/THURSDAY WITH MORE EMPHASIS ON THE 06Z GFS/00Z CMC WHILE
EVENTUALLY TRANSITIONING TO ENSEMBLE MEANS THEREAFTER WITH 70
PERCENT OF THE BLEND FOCUSED ON THE 00Z NAEFS MEAN AND THE
REMAINDER WITH THE 00Z ECMWF ENSEMBLE MEAN.


RUBIN-OSTER

$$





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