ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 PM EDT TUE MAY 14 2013

VALID 12Z SAT MAY 18 2013 - 12Z WED MAY 22 2013

WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS
ALONG WITH ASSOCIATED SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY
DERIVED FROM A CONCENSUS FORECAST BLENDING MAINLY COMPATABLE
GUIDANCE FROM THE 00 UTC ECMWF/CANADIAN AND ECMWF/NAEFS ENSEMBLE
MEANS WITH THE 12 UTC GFS...ALBEIT LEANING AWAY FROM OUTLIER AND
RUN TO RUN INCONSISTENT 00 UTC AND NOW 12 UTC ECMWF RUNS NE
PACIFIC LOW DEVELOPMENT MON ONWARD.  THE RESULTANT COMPOSITE BLEND
ENDED UP LOOKING QUITE A BIT LIKE THE A SMOOTHER 12 UTC GFS FOR
SIMPLICITY.  OVERALL BELOW NORMAL FORECAST SPREAD AS COMPILED BY
COMPARISON OF DOMESTIC AND INTERNATIONAL DETERMINISTIC MODELS AND
ENSEMBLE SYSTEMS PORTENDS ABOVE AVERAGE PREDICTABILITY.

THIS SOLUTION DAYS 4-8 SAT-NEXT WED HIGHLIGHTS WELL DEFINED
MID-UPPER LEVEL TROUGHS AND ASSOCIATED SURFACE SYSTEM REFLECTIONS
LIFTING GRADUALLY DEEPER INTO THE ARCTIC CENTERED TO THE NNW OF
THE STATE AS ADDITIONAL TROUGH ENERGIES SPLIT GRADUALLY SEWD FROM
SRN TO SERN AK AND INLAND INTO WRN CANADA.  MEANWHILE...AMPLE
CLOSED TROUGH AND ORGANIZED LOW/FRONTAL SYSTEM DEVELOPMENT AND
HEAVIER WEATHER/PCPN FOCUS PHASING OVER THE NRN PACIFIC WORKS
STEADILY NEWD OVER THE ALEUTIANS INTO THE SRN BERING SEA AND
EVENTUALLY SWRN THEN WRN AK.

SCHICHTEL