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000
FXAK02 KWNH 221817
PMDAK

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
216 PM EDT WED MAY 22 2013

VALID 12Z SUN MAY 26 2013 - 12Z THU MAY 30 2013

A SERIES OF HARD TO DIAGNOSE ARCTIC IMPULSES WILL BRUSH THE NRN AK
NEXT WEEK WITH LIMITED TIMING/EMPHASIS CONFIDENCE AND IMPACT.
PREDICTABILITY IS BETTER WITH THE IDEA OF A MID-UPPER LEVEL CLOSED
LOW/TROUGH AND PCPN FOCUS ANCHORING NEAR THE WRN ALEUTIANS/SRN
BERING SEA AND EXTENDING INTO SW AK...WITH UNDERCUTTING JET
ENERGIES LEADING TO INCREASED SYSTEM AND WEATHER/PCPN EMPHASIS
DOWNSTREAM/SEWD OVER THE NE PACIFIC OFF SE AK OVER TIME.  THERE
ARE THOUGH LINGERING EMBEDDED SYSTEM RUN TO RUN CONTINUITY ISSUES.
ELSEWHERE...AN INFLATED HEIGHT FIELD IN BETWEEN OFFERS MORE BENIGN
AND WARMED WEATHER CENTERED ACROSS THE INTERIOR.

CONSISTENT WITH UNCERTAINTY AND WITH AN EYE TOWARD
CONTINUITY...WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND
500 MB PROGS ALONG WITH ASSOCIATED SENSIBLE WEATHER GRIDS HAVE
BEEN PRIMARILY DERIVED FROM A BLEND OF 60% 00 UTC ECMWF ENSEMBLE
MEAN WITH 20% EACH OF GFS/NAEFS ENSEMBLE MEANS IN AN EFFORT TO
FOCUS ON THE MOST PREDICTABLE FORECAST ELEMENTS WHILE SMOOTHING
OUT THE LESS PREDICTABLE SMALLER SCALE FORECAST COMPONENTS.

SCHICHTEL

$$