Gale Warning 47, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKST SUN JAN 10 2010

.ANALYSIS AND UPPER LEVELS...
THE PRIMARY WEATHER FEATURE ACROSS THE REGION IS AN UPPER LEVEL LOW
SITUATED 800 MILES SOUTH OF KODIAK ISLAND...WHICH IS POISED TO EJECT
NORTHEASTWARD INTO THE GULF OF ALASKA OVER THE NEXT FEW DAYS. SEVERAL
SMALL SHORTWAVES ARE CURRENTLY ROTATING AROUND THIS LOW. A SHARP
UPPER LEVEL RIDGE SITS OUT AHEAD OF THIS SYSTEM...CURVING NORTHWEST
ALONG THE WEST COAST OF BRITISH COLUMBIA AND THE ALASKA PANHANDLE
BEFORE CRESTING IN THE NORTHERN GULF OF ALASKA. A HIGH PRESSURE RIDGE
IS SLOWLY WEAKENING BUT CONTINUES TO DOMINATE THE NORTH BERING SEA
WHILE AN UPPER LEVEL TROUGH REMAINS STATIONARY OVER THE EASTERN THIRD
OF THE STATE.

AT THE SURFACE...AN ELONGATED LOW PRESSURE SYSTEM IS STACKED UNDER
THE NORTH PACIFIC LOW. HOWEVER...SATELLITE IMAGERY IS BEGINNING TO
INDICATE THE DEVELOPMENT OF A DOUBLE BARREL LOW...WITH THE MAIN LOW
CENTERED 400 MILES SOUTHEAST OF KODIAK AND THE NEWLY SPUN UP
SECONDARY LOW POSITIONED AN ADDITIONAL 600 MILES TO THE SOUTH. AN
OCCLUDED FRONT WITH THIS SYSTEM IS BRINGING LIGHT SHOWERS TO THE
ALASKA PANHANDLE. ELSEWHERE ACROSS THE STATE...A LARGE ARCTIC HIGH
PRESSURE SYSTEM SITS JUST NORTH OF BARROW...BRINGING CONTINUED
SUB-ZERO TEMPERATURES TO THE NORTHERN TWO THIRDS OF THE STATE.

.MODEL DISCUSSION...
OVERALL THE MODELS HAVE A DECENT GRIP ON THE TRAJECTORY OF THE LOW
PRESSURE SYSTEM IN THE NORTH PACIFIC THROUGH THE NEAR SHORT TERM. THE
MODELS HAVE BEEN HAVING A HARDER TIME FORECASTING THE STRUCTURE OF
THIS SYSTEM...WITH ONLY THE LATEST RUNS INDICATING THE DEVELOPMENT OF
THE DOUBLE BARREL LOW FEATURE. THE GFS IS THE MOST AGGRESSIVE IN THE
DEVELOPMENT OF THESE LOW PRESSURE SYSTEMS WHILE THE NAM AND EUROPEAN
PREDICT THE SOUTHERN LOW WILL DISINTEGRATE INTO A TROUGH BY MONDAY
EVENING. THE PROJECTED PATHS OF THE SYSTEMS BEGIN TO DIVERGE BY
TUESDAY MORNING. THE GFS BRINGS THE LOW MUCH CLOSER TO THE COAST OF
SOUTH CENTRAL ALASKA WHILE THE OTHER MODELS KEEP THE SYSTEM FURTHER
WEST AND SOUTH. THE MODELS ARE ALSO RELATIVELY CONSISTENT WITH THE
WEAKENING OF THE BERING SEA HIGH AS AN ARCTIC TROUGH DIGS SOUTHWARD
BY THE MIDDLE OF THE WEEK.

A BLEND OF THE EUROPEAN AND NAM WERE USED IN THE WEST SINCE THEY BEST
DEPICT THE ISOLATED POCKETS OF STRONG WINDS CURRENTLY BEING FELT
ALONG THE COAST. WITH ITS HIGHER RESOLUTION AND GOOD STORM TRACK
CONSISTENCY...THE NAM WAS THE MODEL OF CHOICE IN THE EAST.

.SHORT TERM FORECAST...
SOUTH-CENTRAL ALASKA AND THE GULF...
THE OCCLUDED FRONT ACROSS THE NORTHERN AND WESTERN GULF WILL REMAIN
NEARLY STATIONARY AND WEAKEN THROUGH MONDAY. MOST OF THE RAIN AND
SNOW ASSOCIATED WITH THE FRONT WILL REMAIN OFFSHORE OF MAINLAND
ALASKA EXCEPT FOR THE EXTREME SOUTHEAST CORNER OF THE COPPER RIVER
BASIN WHICH IS EXPECTED TO GET SOME LIGHT SNOW THROUGH MONDAY NIGHT.
THE REST OF SOUTH-CENTRAL ALASKA WILL REMAIN MOSTLY CLEAR AND COLD
WITH AREAS OF GUSTY WINDS THROUGH CHANNELED TERRAIN THROUGH MONDAY
NIGHT. WIND CHILL TEMPERATURES FROM 10 BELOW TO 40 BELOW WILL DEVELOP
ALONG THE ALASKA RANGE NEAR BROAD PASS DURING THE NIGHT AND MORNING
HOURS.

SOUTHWEST ALASKA...
MOSTLY CLEAR AND COLD CONDITIONS WILL REMAIN IN PLACE THROUGH
TUESDAY. BRISK NORTHEAST WINDS WILL CONTINUE TO BLOW ALONG COASTAL
SECTIONS OF BRISTOL BAY AND THE KUSKOKWIM DELTA THROUGH TUESDAY.

BERING SEA AND ALEUTIANS...
THE EAST-WEST TROUGH ACROSS THE BERING SEA WILL REMAIN IN PLACE
THROUGH TUESDAY. WIDELY SCATTERED AREAS OF RAIN SHOWERS AND FOG WILL
PERSIST OF THE ALEUTIANS THROUGH TUESDAY.

.LONG TERM FORECAST...
MID-RANGE MODELS SLOWLY WEAKENS THE GULF LOW THROUGH WEDNESDAY THEN
SHIFTS IT JUST SOUTH OF THE ALASKA PENINSULA WEDNESDAY NIGHT. A WEAK
SOUTHERLY FLOW WILL DEVELOP OVER THE GULF AND BRING MORE MOISTURE
BACK INTO SOUTH-CENTRAL ALASKA. A NEW NORTHWEST PACIFIC STORM WILL
PASS SOUTH OF THE ALEUTIAN CHAIN WEDNESDAY AND THURSDAY. RAIN AND
GALE TO STORM FORCE WINDS WILL MOVE INTO THE ALEUTIANS AND SOUTHERN
BERING SEA FROM WEDNESDAY THROUGH FRIDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING FOR THE KUSKOKWIM DELTA NEAR TOKSOOK BAY.
MARINE...STORM...127 130 132 150 155
         GALE 120 128 140 160 180

KS/NM JAN 10