Gale Warning 19, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST FRI JAN 22 2010

.ANALYSIS AND UPPER LEVELS...
A STRENGTHENING UPPER LEVEL RIDGE RESIDES OVER THE EASTERN BERING SEA
WHILE A WEAK TROUGH OF LOW PRESSURE EXTENDS SOUTHEASTWARD ACROSS
MAINLAND ALASKA...INTO THE GULF OF ALASKA...AND PARALLELS THE WEST
COAST OF NORTH AMERICA TO SOUTHERN CALIFORNIA. AN UPPER LEVEL LOW
RESIDES WITHIN THIS TROUGH OVER THE CENTRAL GULF. THE 190 KT
SUBTROPICAL JET DIVES SOUTHWARD AROUND THE BASE OF THIS TROUGH AND
INTO THE SOUTHWEST US. AN UPPER LEVEL TROUGH IS DIGGING SOUTHWARD
ACROSS THE SEA OF OKHOTSK WITH A 150 KT 300 MB JET STREAK RIDING
ALONG ITS EAST SIDE.

AT THE SURFACE...OFFSHORE WINDS PREVAIL ACROSS MUCH OF SOUTHERN
ALASKA IN RESPONSE TO A FILLING SURFACE LOW PRESSURE CO-LOCATED WITH
THE UPPER LEVEL LOW OVER THE GULF. A SURFACE HIGH PRESSURE RIDGE
EXTENDING ACROSS THE EASTERN ALEUTIANS INTO CENTRAL ALASKA IS FURTHER
ENHANCING THESE NORTHERLY WINDS ACROSS THE WESTERN AND SOUTHERN
PORTIONS OF THE STATE. A STRONG SURFACE FRONT IS SLOWLY WEAKENING
OVER THE WESTERN ALEUTIANS...BUT IS STILL BRINGING STORM FORCE WINDS
TO THE WESTERN BERING.

.MODEL DISCUSSION...

REALLY NOT MUCH TO TALK ABOUT IN THE MODEL DEPARTMENT THIS MORNING
WITH NO REAL INITIALIZATION PROBLEMS AND ALL OF THE MODELS IN
SURPRISINGLY GOOD AGREEMENT THROUGH THE SHORT TERM. THE ECMWF TAKES
THE GULF LOW ON A MORE NORTHERLY TRACK AS THE SYSTEM BEGINS TO WRAP
AROUND A NEW LOW MOVING IN FROM THE SOUTH...AND THUS MAINTAINS THE
LOW AS IT TRACKS SOUTH OF THE ALEUTIANS INSTEAD OF OPENING IT UP INTO
A SHORTWAVE LATE IN THE SHORT TERM. HOWEVER...THIS DISCREPANCY HAS
LITTLE IMPACT ON THE FORECAST. MINIMAL CHANGES WERE MADE TO THE
FORECAST WITH CONFIDENCE IN THE MODELS REMAINING HIGH.

.SHORT TERM FORECAST...
THE LOW OVER THE GULF OF ALASKA WILL DRIFT SOUTH TODAY. STRONG "GAP
FLOW" WINDS OVER SOUTHERN ALASKA WILL CONTINUE INTO THE WEEKEND THEN
ABATE SOMEWHAT ON SATURDAY AS THE LOW MOVES EVEN FURTHER AWAY AND
THE GRADIENT RELAXES.

THE STRONG FRONT OVER THE WESTERN ALEUTIANS WILL CONTINUE TO DRIFT
EAST AND WEAKEN. BY SATURDAY AFTERNOON IT WILL HAVE PROGRESSED TO
THE CENTRAL ALEUTIANS...BUT WILL THEN BEGIN TO RETREAT WESTWARD
SATURDAY NIGHT.

EASTERLY FLOW ALOFT WILL DEVELOP SOUTH OF 60 DEGREES NORTH LATITUDE
OVER THE NORTHERN GULF AND ACROSS THE ALEUTIANS BY THE END OF THE
WEEKEND. FLOW WILL BE WEAK OVER SOUTH CENTRAL AS A WEAK UPPER RIDGE
SETS UP OVER THE AREA.

.LONG TERM FORECAST...
CONDITIONS WILL SLOWLY MOISTEN OVER THE GULF AND SOUTH CENTRAL
ALASKA NEXT WEEK AS WEAK SYSTEMS IN EASTERLY FLOW MOVE ACROSS THE
AREA. FLOW WILL GRADUALLY BECOME MORE SOUTHERLY LATER IN THE WEEK AS
AN UPPER LOW SWINGS INTO THE GULF OF ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM WARNING 175 176.
         GALE WARNING 130 132 150 155 172 185.
         HEAVY FREEZING SPRAY 130 138 150 165.
FIRE WEATHER...NONE.

LUDWIG/KS JAN 10