Gale Warning 487, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM AKDT TUE JUL 6 2010

.MODEL DISCUSSION...
ALL FOUR PRIMARY MODELS IN GOOD AGREEMENT IN REGARDS TO UPPER LEVEL
FEATURES...BUT STRUGGLING TO RESOLVE PATTERN OF WEAK LOWS AND HIGHS
AT THE SURFACE. MAIN SOURCE OF ANGST IS THE MODELS DIFFICULTY
PERCEIVING BOTH STRENGTH AND TRACK OF A SMALL LOW MOVING OUT OF THE
NORTH PACIFIC SOMETIME TONIGHT. LOW TRACKS TO EITHER WESTERN PRINCE
WILLIAM SOUND OR SOUTHERN COOK INLET SOMETIME BETWEEN TOMORROW
MORNING AND TOMORROW AFTERNOON...DEPENDING ON CHOICE OF MODEL. CHOSE
TO TREND EXISTING FORECAST PACKAGE TOWARDS NEW 12Z GFS AS GFS
SOLUTION TAKES A MIDDLE OF THE ROAD APPROACH. BEST GUESS AT THIS TIME
IS A 1008 MB LOW DUE EAST OF KODIAK ISLAND WED MORNING THAT MOVES
INLAND NEAR KAMISHAK BAY WED EVENING. WILL HAVE TO WATCH CLOSELY.

.UPPER LEVELS...
HIGH AMPLITUDE RIDGING IN THE UPPER LEVELS OVER NORTHEAST
PACIFIC...EASTERN GULF OF ALASKA...AND YUKON TERRITORY. LONG WAVE
TROUGH ALOFT EXTENDS FROM HIGH ARCTIC...ACROSS WESTERN ALASKA AND THE
BERING SEA...AND SOUTHWARD INTO THE CENTRAL NORTH PACIFIC. RIDGE
GRADUALLY WEAKENS THROUGH 60 HOURS WHILE LONG WAVE TROUGH BECOMES
MORE DOMINANT. BY 60 HOURS...LONG WAVE TROUGH MORPHS INTO TWO STRONG
CUT OFF LOW CENTERS...ONE OVER HIGH ARCTIC...THEN SECOND JUST SOUTH
OF
THE CENTRAL ALEUTIANS.

.SOUTHCENTRAL ALASKA...
RIDGE OF HIGH PRESSURE ALONG THE GULF COAST HOLDS THROUGH AT LEAST
THURSDAY AFTERNOON. STATIONARY FRONTAL BOUNDARY EXTENDS IN A LINE
FROM NORTHWAY THROUGH CORDOVA AND SOUTHWARD INTO THE CENTRAL NORTH
PACIFIC. SERIES OF WEAK SURFACE LOWS ARE MIGRATING NORTHWARD ALONG
THE FRONT. MOST NOTABLE IS A 1010 MB LOW AT APPROX 47N 151W. FEATURE
IS EXPECTED TO HEAD NORTHWARD TO JUST EAST OF KODIAK ISLAND WED
MORNING THEN WEAKEN AND MOVE INLAND NEAR KAMISHAK BY WED NIGHT.
SYSTEM EXPECTED TO BRING PLENTY OF RAIN TO THE EASTERN GULF
COAST...PRINCE WILLIAM SOUND...AND EASTERN KENAI PENINSULA.
PRECIPITATION ELSEWHERE ACROSS SOUTHCENTRAL ALASKA SHOULD BE LIMITED
TO SCATTERED SHOWERS. PRESSURE GRADIENT ALONG GULF COAST TIGHTENS AS
LOW APPROACHES SOUTHERN MAINLAND. GUSTY WINDS EXPECTED THROUGH THE
USUAL CHANNELED AREAS. DOWNSLOPING SHOULD GENERATE A RAIN SHADOW
EFFECT ACROSS ANCHORAGE...MAT SU...AND NORTHWESTERN KENAI PENINSULA.

.ALEUTIANS AND BERING SEA...
WEAK COMPLEX LOW PRESSURE ACROSS THE BERING SEA BREAKS DOWN BY 48
HOURS. A WEAK LOW SOUTH OF THE WESTERN ALEUTIANS INTENSIFIES TO 968
MB AND MOVES TO APPROX 200 MILES SOUTH OF ADAK BY THU AFTERNOON.
SYSTEM IS EXPECTED TO SPREAD GALE FORCE WINDS ACROSS MOST OF THE
ALEUTIANS AND SOUTHERN BERING SEA.

.SOUTHWESTERN ALASKA...
AIRMASS OVER INTERIOR ALASKA REMAINS SLIGHTLY UNSTABLE. CLOUDY SKIES
AND SCATTERED SHOWERS OVER INLAND AREAS CONTINUE THROUGH AT LEAST
THURSDAY. EASTERLY FLOW DEVELOPS ACROSS THE AREA ON WEDNESDAY AND
PUSHES AREAS OF LOW CLOUDS PATCHY FOG AND DRIZZLE AWAY FROM THE
COAST.

.LONG TERM FORECAST...
UPPER LEVEL STORM TRACK BECOMES MORE CONDUCIVE TO STEERING LARGE
NORTH PACIFIC STORMS INTO SOUTHWESTERN AND SOUTHCENTRAL ALASKA.
CONTINUED CLOUDY AND COOL FOR MOST OF SOUTHCENTRAL AND SOUTHWESTERN
ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 172 175
FIRE WEATHER...NONE.

ASB JUL 10