THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD


ALASKA EXTENDED FORECAST DISCUSSION




ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
351 PM EDT THU AUG 28 2014

VALID 12Z MON SEP 01 2014 - 12Z FRI SEP 05 2014

A SIGNIFICANT ARCTIC VORTEX DESCENDS TO THE NORTH SLOPE OF ALASKA
NEXT WEEK ALLOWING A PROLONGED PERIOD OF UPPER-LEVEL TROUGHING
FROM THE ARCTIC OCEAN THROUGH THE INTERIOR. EXPECT BELOW NORMAL
TEMPS FOR MUCH OF ALASKA AS 500/700 MB HEIGHT ANOMALIES WILL
CENTER 2-3 STANDARD DEVIATIONS BELOW NORMAL NORTH OF THE ARCTIC
CIRCLE. THE PATTERN SHOULD ALLOW MODEST LINGERING IMPULSES AND
SURFACE DEVELOPMENT UNDERNEATH OVER THE ALASKAN SRN/SERN TIER BOTH
OVER/FROM THE GULF OF AK AND LATE WEEK UPSTREAM SOUTH OF THE
ALEUTIANS.

MODEL AND ENSEMBLE SOLUTIONS FROM THE 12 UTC GFS AND 00 UTC ECMWF
AND 00 UTC GFS/ECMWF/NAEFS ENSEMBLE MEANS SEEM TO CLUSTER PRETTY
WELL MON INTO TUE BEFORE INCREASING DETERMINISTIC FORECAST SPREAD
LENDS MORE OF AN ENSEMBLE MEAN BASED FORECAST THROUGH THE
REMAINDER OF NEXT WEEK. THE ENSEMBLE MEANS SEEM REASONABLY
COMPATABLE AND OFFER BETTER RUN TO RUN CONTINUITY.

SCHICHTEL





Last Updated: 351 PM EDT THU AUG 28 2014