Prognostic Meteorological Discussion
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FXAK02 KWNH 271919
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
319 PM EDT SAT AUG 27 2016

VALID 12Z WED AUG 31 2016 - 12Z SUN SEP 04 2016

...GUIDANCE/UNCERTAINTY ASSESSMENT AND WEATHER
HIGHLIGHTS/THREATS...

AN AMPLIFIED MID-UPPER LEVEL FLOW PATTERN NEAR ALASKA SHOULD BE
HIGHLIGHTED MIDWEEK BY A BERING STRAIT/ERN BERING SEA RIDGE
BETWEEN CLOSED LOWS/TROUGHS NEAR THE WRN ALEUTIANS AND ERN GULF OF
AK. LEAD ENERGY ALOFT AND AN ASSOCIATED SURFACE LOW WILL DIG
SLOWLY SEWD TO FOCUS PCPN AND UNSETTLED WEATHER WED/THU OVER THE
ERN GULF OF AK/SERN AK. THIS LEAVES A LESS DEFINED WEAKNESS ALOFT
OVER THE ALASKAN INTERIOR AS THE AFOREMENTIONED BERING STRAIT
RIDGE RETROGRADES INTO NERN RUSSIA. MEANWHILE...THE EXTRATROPICAL
TRANSITION OF TYPHOON LIONROCK OFF ERN ASIA SHOULD HELP AMPLIFY
THE OVERALL DOWNSTREAM FLOW FROM THE MID TO UPPER LATITUDES. THIS
SHOULD FAVOR A LESS PROGRESSIVE TREND FOR SIGNIFICANT MID-LATE
WEEK DOWNSTREAM LOW DEVELOPMENT NEAR THE WRN ALEUTIANS. PREFER AN
ENSEMBLE MEAN BASED SOLUTION WITH EMPHASIS ON THE 00 UTC NAEFS
ENSEMBLE MEAN TO BEST MATCH CONTINUITY AND FAVORED SLOWED
PROGRESSION TREND. RECENT GEFS/ECMWF ENSEMBLE MEANS ARE ALSO
GENERALLY IN LINE EVEN THOUGH AMPLE DETERMINISTIC MODEL RUN TO RUN
VARIANCE REMAINS. THIS SIGNIFICANT LOW MAY GRADUALLY WORK INTO SRN
BERING SEA BY NEXT WEEKEND IN AMPLIFIED FLOW AND SPREAD WIDESPREAD
UNSETTLED WEATHER/RAINFALL DOWNSTREAM ACROSS THE ALEUTIANS/BERING
SEA INTO SW/WRN THEN SRN AK.

SCHICHTEL

$$





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