Gale Warning 45, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
1155 AM AKST SUN JAN 11 2009

.SHORT TERM... BIG PROBLEM TODAY IS SUBTROPICAL SOURCE REGION
FOR T-BONE SHAPED WEATHER SYSTEM/FRONT MOVING INTO SE TONIGHT.
COMPARE GFS AND NAM QPF TO AMSU AND THERE IS LOTS OF JUICE. WILL
ISSUE FLOOD WARNING FOR THE FOLLOWING ZONES FOR WATER ON SNOW:
25 26 28 29. CONFIDENCE HIGH THAT THERE WILL BE PROBLEMS WITH
STREETS AND ROOFS.

THE LEAST FAVORITE MODEL TODAY IS THE GFS WHICH DRIVES THE MAIN
SFC LOW CENTER INLAND AT 36 HRS VT 00Z TUE. USED THE NAM FOR WIND
AND BLEND OF GFS AND NAM FOR QPF.

.LONG TERM...ONE LARGE SCALE WARM REGIMEN AFTER ANOTHER.
CHANGE TO FLOW WITH TROPICAL SOURCE REGION HAS BEGUN. THE GLOBAL
COMPOSITE IR SHOWS THE MERIDIONAL JET STREAM EXTENDING SOUTH OF THE
ALASKA PENINSULA BY ABOUT 2500 MILES.

A SECOND SECTION OF POLAR FRONT ZONE IS CROSSING THE DATELINE
IN A BROAD BAND FROM 300 TO 1200 NM S OF THE CHAIN. THIS SECOND
SECTION OF POLAR FRONT WILL PROVIDE THE STRONG WARMING FROM LOW
LATITUDES FOR DAYTIME TUE ONWARD.

MODELS: GOOD MODEL CONSENSUS AND HIGH FORECASTER CONFIDENCE THAT
THE THAT THE LARGE SCALE WARM UP AND CHANGE TO RAIN THAT IS
OCCURRING AT THIS TIME WILL RESULT IN TEMPERATURES PERSISTING
ABOVE FREEZING AND PERIODIC BANDS OF HEAVY RAIN. THE CONFIDENCE IS
HIGH FOR THESE WARMER CONDITIONS THROUGH AT LEAST FRI NIGHT.

WE HAVE LESS CONFIDENCE IN THE MODEL SOLUTIONS FOR THE
INDIVIDUAL RAIN BANDS AND WIND EVENTS ASSOCIATED WITH
INDIVIDUAL FRONTAL WAVES.  RUN TO RUN CHANGES ARE SIGNIFICANT:
GFS MSLP MODEL DRIFT FOR 36 HR, AND 60 HR, INDICATE MODEL
ADJUSTMENTS.  THESE COMPLICATIONS WITH THE INDIVIDUAL
DETERMINISTIC MODELS ENCOURAGE THE USE OF HPC GUIDANCE, AND
THE USE OF MOS THAT ARE BEING FACTORED IN WITH INCREASING
WEIGHT FOR 12Z THU ONWARD.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM AKST MONDAY FOR
     AKZ017-022-023-027.
MARINE...GALE WARNING FOR PKZ012-013-022-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-021-031>036.

JCC/JBT