Small Craft Advisory 615, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM AKDT TUE AUG 4 2009

.ANALYSIS AND UPPER LEVELS...
ALOFT...THE RIDGE OVER THE ALCAN BORDER CONTINUES TO SLIP EAST WHILE
A LARGE TROUGH AND ASSOCIATED CLOSED LOW REMAIN OVER THE BERING SEA
AND ALEUTIANS. VARIOUS SHORTWAVES ARE ROTATING AROUND THE PERIPHERY
OF THE UPPER LOW...WITH THE MOST NOTABLE SHORTWAVE MOVING NORTHWARD
OUT OF THE WESTERN GULF.

AT THE SURFACE...WEAKENING HIGH PRESSURE IS OVER THE NORTHEASTERN
GULF COAST. A LARGE LOW IS EVIDENT ON SATELLITE IMAGERY...CURRENTLY
LOCATED NORTHWEST OF DUTCH HARBOR. A WEATHER FRONT EXTENDING FROM
THIS LOW STRETCHES ACROSS THE AKPEN AND SOUTHWEST AK INTO THE WESTERN
GULF. A TRIPLE POINT LOW BEGINNING TO DEVELOP ALONG THIS FRONT NEAR
KODIAK ISLAND WILL BE REINFORCED BY THE AFOREMENTIONED SHORTWAVE.

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT THROUGH THE END OF THE WEEK WITH ALL
SOLUTIONS AGREEING ON SYNOPTIC FEATURES. DIFFERENCES ARISE SHORT TERM
WITH REGARDS TO THE TRIPLE POINT LOW FORMING IN THE WESTERN GULF...AS
WELL AS HOW THE LOW IN THE BERING WILL TRANSITION INTO THE GULF. THE
NAM SOLUTION SEEMS TO BE HANDLING THE TRIPLE POINT LOW FORMATION THE
BEST...WITH A CLOSED LOW FORMING OVER KODIAK ISLAND TONIGHT...MOVING
TO NEAR MONTAGUE ISLAND WHILE DISSIPATING WEDNESDAY NIGHT. THE ECMWF
SOLUTION IS FAVORED AS WE HEAD INTO THE WEEKEND DUE TO BETTER
HANDLING OF THE LOW MOVING FROM THE BERING INTO THE GULF.

.SHORT TERM FORECAST...
.SOUTHCENTRAL...
CLOUDS AND MOISTURE WILL CONTINUE TO MOVE INLAND ACROSS SOUTHCENTRAL
AS THE FRONT MOVES INTO THE REGION. RAIN WILL BECOME LIKELY BY
TOMORROW MORNING ACROSS MOST OF THE REGION...EXCEPT THE COPPER RIVER
BASIN WHERE DOWNSLOPING WILL LIMIT PRECIP TO SCATTERED SHOWERS.
EXPECT RAIN TO GRADUALLY CLEAR OUT ON WEDNESDAY...WITH SHOWERS
PERSISTING THROUGHOUT THE AREA THROUGH THE DAY ON THURSDAY.
TEMPERATURES WILL REMAIN SEASONABLE UNDER MAINLY CLOUDY SKIES.

.SOUTHWEST...
RAIN AND WINDS WILL BE ON THE DECREASE THIS EVENING AND TONIGHT AS
THE AFOREMENTIONED FRONT WEAKENS OVER THE REGION. SHOWERS WILL
PERSIST THROUGH THE END OF THE WEEK AS THE UPPER LOW CONTINUES TO
INFLUENCE THE AREA. MOISTURE WILL BE ON THE INCREASE ONCE AGAIN LATE
THURSDAY AS THE BERING LOW BEGINS TO MOVE EASTWARD INTO THE GULF.

.BERING SEA AND ALEUTIANS...
SHOWERS AND GUSTY WINDS WILL CONTINUE ACROSS THE CENTRAL AND EASTERN
ALEUTIANS...AS WELL AS THE PRIBILOFS...AS THE AFOREMENTIONED SURFACE
LOW REMAINS RELATIVELY STATIONARY THROUGH LATE THURSDAY. THE WESTERN
ALEUTIANS ARE EXPECTED TO REMAIN FAIRLY QUIET UNTIL THURSDAY NIGHT
WHEN A FRONT ENCROACHES FROM THE WEST.

.LONG TERM FORECAST...
FLOW IS EXPECTED TO BECOME MORE PROGRESSIVE ACROSS THE AREA WITH
INDIVIDUAL FEATURES PASSING THROUGH QUICKLY. TIMING IS DIFFICULT TO
NAIL DOWN WITH INDIVIDUAL FEATURES THIS FAR OUT...BUT GENERALLY
EXPECT PERIODS OF UNSETTLED WEATHER WITH SEASONABLE TEMPERATURES
ACROSS THE REGION AS WE HEAD INTO NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 130
FIRE WEATHER...RED FLAG WARNING 141

NRH AUG 09