ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
149 PM EDT FRI MAY 24 2013

VALID 12Z TUE MAY 28 2013 - 12Z SAT JUN 01 2013

THE ALASKA AND VICINITY OVERALL WEATHER PATTERN EVOLUTION REMAINS
WELL CAPTURED BY THE BULK OF MEDIUM RANGE MODEL AND ENSEMBLE
GUIDANCE...ALBEIT WITH LINGERING SMALLER SCALE EMBEDDED SYSTEM RUN
TO RUN CONTINUITY ISSUES.  IN THIS FLOW...A SERIES OF ARCTIC
IMPULSES BRUSH NRN AK NEXT WEEK WITH LIMITED TIMING/EMPHASIS
CONFIDENCE.  PREDICTABILITY SEEMS BETTER NEXT WEEK WITH THE IDEA
OF A MID-UPPER LEVEL CLOSED LOW/TROUGH AND PCPN FOCUS OUT FROM THE
ALEUTIANS/SRN BERING SEA AND SW AK.  AMPLE UNDERCUTTING JET
ENERGIES LEAD TO INCREASED SYSTEM AND WEATHER/PCPN EMPHASIS
DOWNSTREAM/SEWD OVER THE NE PACIFIC WELL OFF SE AK DURING THE
WEEK...BUT ULTIMATELY CLOSED TROUGH REFORMATION ALOFT AND SURFACE
CYCLOGENESIS CENTERS BACK SOUTH OF THE ALEUTIANS IN THE DAYS 6-8
TIME FRAME.  MEANWHILE ELSEWHERE...AN INFLATED HEIGHT FIELD IN
BETWEEN OFFERS QUITE WARMED WEATHER CENTERED ACROSS THE INTERIOR.

CONSISTENT WITH LINGERING UNCERTAINTY AND WITH AN STRONG PUSH TO
MAINTAIN CONTINUITY...WPC ALASKAN MEDIUM RANGE SURFACE
FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH ASSOCIATED SENSIBLE
WEATHER GRIDS HAVE BEEN PRIMARILY DERIVED FROM A NEAR EQUAL BLEND
OF THE 00 UTC ECMWF WITH COMPATABLE 00 UTC GFS/ECMWF/NAEFS
ENSEMBLE MEANS.  THIS FOLLOWS A CONTINUING EFFORT TO PROVIDE AS
MUCH SPECIFICS AS POSSIBLE CONSISTENT WITH UNCERTAINTY WHILE
FOCUSING ON THE MORE PREDICTABLE FORECAST ELEMENTS AND SMOOTHING
OUT THE LESS PREDICTABLE COMPONENTS.

SCHICHTEL