ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
438 PM EDT FRI JUL 08 2016

VALID 12Z TUE JUL 12 2016 - 12Z SAT JUL 16 2016

The 8/00Z ECENS AND 8/06Z GEFS MEANS HAVE A RATHER GOOD HANDLE ON
THE EVOLUTION OF THE 'BLOCKY' PATTERN AND SPLIT-FLOW IN THE
NORTHERN BERING SEA THROUGH THE END OF DAY 8.

STILL A FEW DIFFERENCES FOR DAY 6 AND BEYOND...

IN THE SOUTHERN PORTION OF THE SPLIT-FLOW PATTERN---
MAINLY CONCERNING THE LIFE CYCLE OF BENIGN AND TRANSITORY SURFACE
FEATURES MIGRATING BENEATH A CUTOFF UPPER LOW THAT WILL BECOME
QUASI-STATIONARY ALONG 50N-52N (IN THE GULF OF ALASKA). TO
MAINTAIN THE BEST CONTINUITY --- BLENDED THE ECENS/GEFS MEANS AND
THE 8/00Z DETERMINISTIC GFS TO PRODUCE THE ALASKA GRID FILES AND
MASS FIELD GRAPHICS.

IN THE NORTHERN PORTION OF THE SPLIT-FLOW (ACROSS THE ARCTIC)---
COULD USE THE 8/00Z GFS RUN THROUGH THE END OF DAY 5...BEFORE THE
DEPTH OF THE ARCTIC SHORTWAVE BECOMES A CONCERN. THE ISSUE BEING
--- TIMING OF A DEEP FRONTAL PROGRESSION ACROSS NORTHWEST ALASKA
AND ITS ABILITY TO MIGRATE THROUGH THE CENTRAL AND EAST CENTRAL
INTERIOR. THE MEANS DO PROVIDE A CONSISTENT SIGNAL FOR MID-LEVEL
SHORTWAVE ENERGY PROGRESSION ACROSS THE NORTH...BUT THE
DETERMINISTIC GUIDANCE SUGGESTS A MORE COMPLEX PATTERN EMERGES
AFTER DAY 7. RATHER THAN WAVER ON THE RUN-TO-RUN DETAILS BETWEEN
GFS/ECMWF SOLUTIONS---THOUGHT THE MEANS DO A BETTER JOB OF
MAINTAINING CONTINUITY (UNTIL THERE IS SLIGHTLY BETTER AGREEMENT. 

VOJTESAK