Small Craft Advisory 647, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT THU AUG 9 2007

.MODEL DISCUSSION...
MODELS HAVE VERY SIMILAR SOLUTIONS OVER THE ALASKAN MAINLAND THROUGH
SUNDAY THOUGH THE NAM MODEL HOLDS THE RIDGE OVER WESTERN ALASKA WHILE
THE GFS HAS IT OVER SOUTH CENTRAL ALASKA SUNDAY. OVER THE BERING
SEA...THE GFS MODEL MOVES THE LOW SOUTH OF SHEMYA IN THE THE NORTHERN
BERING WHILE THE NAM MODEL MOVES THE CENTER INTO THE WESTERN BERING
BY SATURDAY NIGHT. COMPARING BOTH MODELS TO THE NOGAPS AND UKMET
MODELS, THE GFS HAS A BETTER SOLUTION.

.ANALYSIS AND UPPER LEVELS...
THE UPPER RIDGE OVER WESTERN ALASKA HAS BUILT UP A BIT MORE OVER
NIGHT. THE UPPER LOW OVER THE WESTERN BERING SEA REMAIN
QUASI-STATIONARY. A WEAKER UPPER LOW OVER THE WESTERN COPPER RIVER
BASIN CONTINUES TO MOVE SOUTH.

SOUTHCENTRAL ALASKA CONTINUES TO BE FAIRLY UNSTABLE TODAY.
THUNDERSTORMS ARE POSSIBLE OVER THE SUSITNA VALLEY AND COPPER RIVER
BASIN THIS AFTERNOON AND EVENING. A WEAK SURFACE HIGH OVER SOUTHWEST
ALASKA HAS PRODUCED AREAS LOW CLOUDS AND FOG IN THE MORNING. THESE
CONDITIONS WILL IMPROVE LATER IN THE DAY BUT WILL COME BACK TONIGHT.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
UNSTABLE CONDITIONS REMAIN OVER THE INTERIOR. AFTERNOON AND EVENING
SHOWERS AND POSSIBLE THUNDERSTORMS WILL FORM OVER THE SUSITNA VALLEY
AND COPPER RIVER BASIN TODAY. THE CLOUDS ARE EXPECTED TO CLEAR
OVERNIGHT AND SKIES WILL REMAIN MOSTLY CLEAR FRIDAY AND SATURDAY.

SOUTHWEST ALASKA...
THE AREA OF HIGH PRESSURE OVER WESTERN ALASKA WILL MOVE INTO SOUTH
CENTRAL ALASKA THROUGH THE WEEKEND. A WEATHER FRONT DEVELOPING OVER
THE CENTRAL BERING SEA FRIDAY WILL MOVE INTO THE INTO THE SOUTHWEST
COAST SATURDAY AND MOVE INLAND SATURDAY NIGHT. AREAS OF DENSE FOG IS
EXPECTED TO REFORM ALONG THE COASTAL SECTIONS OF BRISTOL BAY AND THE
KUSKOKWIM DELTA LATE TONIGHT AND FRIDAY MORNING. RAIN WILL MOVE INTO
THE KUSKOKWIM DELTA SATURDAY MORNING AND MOVE INTO THE SOUTHWEST
INTERIOR BY EVENING.

BERING SEA AND ALEUTIANS...
A WEAK LOW OVER THE WESTERN BERING SEA WILL DISSIPATE FRIDAY MORNING.
A WEAK LOW SOUTH OF THE WESTERN ALEUTIANS WILL MOVE NORTH AND
STRENGTHEN TO 998 MB OVER THE WESTERN BERING SEA FRIDAY NIGHT THEN
WEAKEN TO 1005 MB OVER THE NORTHERN BERING SEA SATURDAY NIGHT. A
MODERATE WEATHER FRONT WILL MOVE INTO THE CENTRAL AND EASTERN BERING
SEA FRIDAY AND WILL MOVE TOWARD THE SOUTHWEST COAST OF ALASKA FRIDAY
NIGHT.

.LONG TERM FORECAST...
THE UPPER RIDGE OVER SOUTH CENTRAL ALASKA SUNDAY WILL DEVELOP INTO A
CLOSED HIGH OVER THE KENAI PENINSULA AND PRINCE WILLIAM SOUND
TUESDAY. A WEAK SHORT WAVE WILL MOVE THROUGH THE RIDGE SUNDAY. THIS
SHOULD KEEP SOUTH CENTRAL ALASKA MOSTLY SUNNY THROUGH TUESDAY THOUGH
CLOUDS AND A SLIGHT CHANCE OF RAIN CAN BE EXPECTED ON SUNDAY.

SOUTHWEST FLOW WILL PERSIST OVER SOUTHWEST ALASKA SUNDAY THROUGH
TUESDAY. THIS WILL KEEP PARTLY SUNNY TO MOSTLY CLOUDY SKIES OVER THE
AREA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

NM AUG 07