Gale Warning 738, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT SAT OCT 13 2007

.MODEL DISCUSSION...
MODELS INITIALIZE ABOUT THE SAME BUT SIGNIFICANT DIFFERENCES DEVELOP
BETWEEN THE GFS AND NAM FROM SUNDAY AFTERNOON ONWARD. A TRIPLE POINT
LOW DEVELOPING NEAR DUTCH HARBOR SUNDAY MORNING IS MUCH STRONGER AND
MOVES EAST FASTER ON THE NAM MODEL THAN THE GFS MODEL. THE UKMET,
NOGAPS AND THE CANADIAN OPERATIONAL MODEL ARE IN BETTER AGREEMENT
WITH THE NAM THAN THE GFS. SO THE NAM IS THE PREFERRED MODEL.

.ANALYSIS AND UPPER LEVELS...
A 500 MB LOW OVER NEAR SAINT LAWRENCE ISLAND WITH A TROUGH EXTENDING
THROUGH NUNIVAK ISLAND AND KUSKOKWIM BAY HAS BROUGHT SNOW TO THE
KUSKOKWIM DELTA.  ANOTHER WEAK UPPER LOW OVER PRINCE WILLIAM SOUND,
WHICH IS STACKED WITH THE SURFACE LOW, CONTINUES TO WEAKEN.

A WEAKENING LOW SOUTH OF PRINCE WILLIAM SOUND HAD BROUGHT RAIN AND
SOME SNOW AT THE HIGHER ELEVATIONS TO THE CENTRAL GULF COAST AND
KENAI PENINSULA THIS MORNING. CURRENT RADAR IMAGES FROM THE MIDDLETON
ISLAND AND KENAI RADAR SHOW BANDS OF SHOWERS ROTATING AROUND THE LOW.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA AND THE GULF OF ALASKA...
THE LOW SOUTH OF PRINCE WILLIAM SOUND WILL MOVE INTO THE LOWER COOK
INLET TONIGHT THEN DISSIPATE SUNDAY. A SECONDARY LOW WILL DEVELOP
OVER THE SUSITNA VALLEY TONIGHT AND WILL ALSO DISSIPATE SUNDAY.
PRECIPITATION WILL BE MOSTLY RAIN SHOWERS ALONG THE CENTRAL GULF
COAST, KENAI PENINSULA, THE ANCHORAGE BOWL AND THE MATANUSKA AND
SUSITNA VALLEYS THIS AFTERNOON AND AND EVENING CHANGING TO MIXED RAIN
AND SNOW SHOWERS TONIGHT. SCATTERED SNOW SHOWERS WILL PERSIST OVER
THE COPPER RIVER BASIN THROUGH TONIGHT.

AN UPPER TROUGH ALONG THE SOUTHWEST COAST WILL MOVE THROUGH KODIAK
ISLAND TONIGHT AND INTO THE KENAI PENINSULA, PRINCE WILLIAM SOUND AND
ANCHORAGE BOWL SUNDAY NIGHT THROUGH MONDAY MORNING. MORE RAIN ANDS
SNOW SHOWERS ARE EXPECTED TO MOVE THROUGH THE AREA WITH THIS SYSTEM.

ANOTHER LOW WILL MOVE INTO THE SOUTHERN GULF MONDAY AFTERNOON.

SOUTHWEST ALASKA...
THE UPPER TROUGH ALONG THE SOUTHWEST COAST WILL MOVE INLAND OVER THE
KUSKOKWIM DELTA AND BRISTOL BAY ZONE TONIGHT AND INTO THE KUSKOKWIM
VALLEY ZONE SUNDAY. AREAS OF SNOW OVER THE KUSKOKWIM VALLEY WILL
DIMINISH TONIGHT. AREAS OF SNOW WILL MOVE THROUGH THE BRISTOL BAY
ZONE TONIGHT AND THE KUSKOKWIM VALLEY SUNDAY.

A UPPER RIDGE OVER THE BERING SEA WILL DISPLACE THE UPPER TROUGH OVER
SOUTHWEST ALASKA LATE SUNDAY THROUGH MONDAY. SKIES WILL PARTIALLY
CLEAR BY MONDAY.

BERING SEA AND ALEUTIANS...
LOW PRESSURE OVER THE WESTERN BERING WILL MOVE THROUGH THE SOUTHERN
BERING SEA TONIGHT AND SUNDAY THEN CROSS THE ALASKA PENINSULA SUNDAY
NIGHT. STORM FORCE WINDS WILL MOVE INTO THE WESTERN ALEUTIANS TONIGHT
AND INTO THE CENTRAL ALEUTIANS SUNDAY AND SUNDAY EVENING.

.LONG TERM FORECAST...
THE LOW OVER THE SOUTHERN GULF MONDAY WILL REMAIN OVER THE GULF
THROUGH THURSDAY. SHOWERS WILL CONTINUE ALONG THE GULF COAST, KENAI
PENINSULA AND KODIAK ISLAND. A WEAKER LOW PRESSURE SYSTEM OVER THE
NORTHERN BERING SEA MONDAY WILL PARK ITSELF OVER THE EASTERN BERING
TUESDAY AND SLOWLY WEAKEN THROUGH WEDNESDAY NIGHT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM 172, 175, 176.
         GALE 155, 170.
FIRE WEATHER...NONE.

NM OCT 07