ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
216 PM EDT FRI MAY 17 2013

VALID 12Z TUE MAY 21 2013 - 12Z SAT MAY 25 2013

UPPER PATTERN ACROSS MUCH OF THE NORTHERN HEMISPHERE BETWEEN ASIA
AND EUROPE VIA NORTH AMERICA REMAINS RATHER BLOCKY. UPPER RIDGING
INITIALLY POKING INTO INTERIOR ALASKA OUT OF THE GULF SHOULD EASE
BACK SOUTH AS TROUGHING HOLDS OVER THE BERING SEA. THE MODELS AND
ENSEMBLES SHOW BETTER THAN AVERAGE AGREEMENT AT LEAST EARLY IN THE
PERIOD THOUGH THE SYNOPTIC SETUP FAVORS LOWER THAN AVERAGE
CONFIDENCE IN SPECIFICS. WITH A RELATIVELY STABLE UPPER LOW NEAR
THE BERING STRAIT... AFTER THE INITIAL SFC FRONT PUSHES NORTHWARD
ALONG WESTERN ALASKA... ENERGY WILL LIKELY ROTATE AROUND IT FROM
NORTHEAST ASIA BUT TIMING THESE IMPULSES IS DIFFICULT.
NEVERTHELESS... THE LARGER PICTURE REMAINS CONSISTENT AMONG THE
GUIDANCE. A BLEND BETWEEN THE 12Z GFS AND 00Z ECMWF PROVED
COMPATIBLE TO THE ENSEMBLE MEANS AND WAS USED AS THE BASE OF THE
FORECAST DAYS 4-6... TAKING A SFC LOW NORTHWARD THROUGH THE BERING
AS THE SFC FRONT WEAKENS OVER WESTERN ALASKA. THE SOUTHERN PORTION
OF THE FRONT SHOULD LINGER SOUTH OF THE ALEUTIANS AND SHOULD
PROBABLY SEND SFC WAVES NORTHEASTWARD TOWARD SOUTHERN/COASTAL
AREAS. TO THE NORTHWEST... ADDITIONAL ENERGY MAY FORM ANOTHER SFC
BOUNDARY THAT CRUISES THROUGH THE SOUTHERN BERING. TRENDED TOWARD
THE ENSEMBLE MEANS FOR DAYS 7-8 GIVEN LOWER CONFIDENCE IN
TIMING/STRENGTH OF ANY SUCH BOUNDARIES.

THE PATTERN SHOULD BE FAIRLY WET ALONG THE WEST AND SOUTH COASTS
BUT THEN RELATIVELY DRY EAST OF THE KENAI PENINSULA. TEMPERATURES
SHOULD MODERATE FROM THE CHILLY AIRMASS CURRENTLY IN PLACE TO NEAR
NORMAL IN THE WEST TO ABOVE NORMAL IN THE EAST AND PANHANDLE...
WHERE A NICE STRETCH OF MILD/DRY WEATHER SHOULD PERSIST THANKS TO
OFFSHORE FLOW.


FRACASSO