Small Craft Advisory 671, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT THU SEP 4 2014

.ANALYSIS AND UPPER LEVELS...CONVERGENCE OF THE NORTHERN AND
SOUTHERN JETS HAS OCCURRED ACROSS SOUTHERN MAINLAND WITH
WIDESPREAD RAINFALL, CAUGHT UP IN THE SOUTHERN BRANCH, MOVING
NORTHEAST. TROUGH AXIS OVER BRISTOL BAY DOESN'T CROSS
SOUTHCENTRAL ALASKA UNTIL FRIDAY EVENING AT WHICH TIME RAIN
CHANGES TO SHOWERS. HEAVIEST RAIN GRAZES THE NORTH GULF COAST AS
UPPER FLOW SHIFTS IT OFF TO YAKUTAT AND THE NORTHERN PANHANDLE.
NEXT UPPER TROF, IN THE DRIER NORTHERN BRANCH, DROPS INTO COOK
INLET SATURDAY EVENING FOR AN INCREASE IN SHOWERS, MAINLY ALONG
AND OVER THE MOUNTAINS. THIS THING WILL MOVE OUT AS FAST AS IT
ROLLS IN, SO WITH THE EXCEPTION OF SHOWERS IN THE PRINCE WILLIAM
SOUND AND THE COPPER RIVER BASIN ZONES, SUNSHINE WILL BE ON THE
INCREASE SUNDAY AS UPPER HIGH PRESSURE TRIES TO TAKE CONTROL OF
THE FORECAST AREA EAST OF 160W OR SO.

WEAK UPPER RIDGING OVER BERING BUILDS ACROSS THE ALASKA PENINSULA
AND EASTERN BERING FRI AND SATURDAY THEN GIVES WAY TO THE NEXT
UPPER LOW MOVING TO AROUND 178W SUNDAY AFTERNOON. THIS WILL DRIVE
A FRONT EASTWARD TO THE FOX ISLANDS SATURDAY AFTERNOON WITH RAIN
DEVELOPING ALONG THE ALASKA PENINSULA SATURDAY NIGHT CONTINUING
THROUGH SUNDAY. FRONT SHOULD HOLD TOGETHER ENOUGH TO SPREAD RAIN
TO KODIAK ISLAND SUNDAY NIGHT.

&&

.MODEL DISCUSSION...NAM AND GFS LOOK PRETTY GOOD THROUGH THE
WEEKEND AND EARLY NEXT WEEK.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...
RAIN THROUGH TONIGHT AND EARLY FRIDAY SLOWLY BECOMING MORE
SHOWERY BY FRIDAY AFTERNOON. SHOWERS TAPER OFF FROM WEST TO EAST
FRIDAY EVENING BUT LINGER ALONG THE MOUNTAINS MUCH OF THE NIGHT
FOLLOWED BY A MOSTLY DRY DAY SATURDAY, WITH A LITTLE SUN POSSIBLE.
SHOWERS WILL INCREASE AGAIN SATURDAY NIGHT AS THE NEXT UPPER LOW
DROPS INTO COOK INLET FROM THE NORTHWEST. THIS TROF SHOULD MOVE
RAPIDLY OUT OF THE AREA SO SUNDAY AFTERNOON SHOULD SEE A FAIR
AMOUNT OF SUNSHINE.

SOUTHWEST ALASKA...RAIN OVER BRISTOL BAY SLOWLY BECOMES MORE
SHOWERY AND TAPERS OFF FRIDAY WITH ONLY SOME SCATTERED LINGERING
SHOWERS ALONG THE ALEUTIAN AND ALASKA RANGES FRIDAY NIGHT. A
SURFACE HIGH CENTERED OVER ST LAWRENCE ISLAND WILL BRING MOSTLY
SUNNY SKIES TO THE KUSKOKWIM DELTA AND NUNIVAK ISLAND FRIDAY,
SATURDAY AND SUNDAY.

BERING SEA/ALEUTIANS...HIGH PRESSURE FRIDAY MOVES EASTWARD
SATURDAY AS A 982 MB LOW MOVES TO NEAR OR JUST WEST OF ADAK BY
SUNDAY MORNING. GALE FORCE WINDS FROM THE EAST NORTHEAST ARE
LIKELY LATE FRIDAY INTO SATURDAY. WITH BREEZY WET CONDITIONS INTO
THE FIRST OF NEXT WEEK. MODELS MOVE THE LOW CENTER TO THE GREATER
DUTCH HARBOR AREA TUE MORNING AS DRIER NORTHWEST FLOW MOVES IN
ACROSS THE WESTERN AND CENTRAL ZONES.

&&

.LONG TERM FORECAST...
THE EXTENDED FORECAST WILL BEGIN WILL A LARGE SUB 980 MB LOW
PRESSURE SYSTEM APPROACHING THE CENTRAL ALEUTIANS LATE THIS
WEEKEND AND THEN GRADUALLY TRACKING EASTWARD ALONG THE CHAIN
DURING THE WEEK. THIS WILL RESULT IN ABUNDANT RAINFALL AND GUSTY
WINDS OVER A WIDE SWATH OF THE BERING SEA THROUGH MUCH OF NEXT
WEEK. MEANWHILE...THE SOUTHERN MAINLAND WILL BEGIN NEXT WEEK
LARGELY PRECIPITATION FREE UNDER THE INFLUENCE OF HIGH PRESSURE
AS AN UPPER TROUGH DEPARTS TO THE EAST. THIS WILL BE FOLLOWED BY A
QUICK TRANSITION BACK TO A WETTER PATTERN BY TUESDAY AS THE
BERING LOW SHIFTS EASTWARD AND AN ASSOCIATED FRONT REACHES THE
COAST...WITH BROAD SOUTH TO SOUTHWESTERLY FLOW BECOMING RE-
ESTABLISHED ACROSS THE REGION THROUGH THE END OF THE WEEK.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING 175 176 177 178.
FIRE WEATHER...NONE.

&&

DPERCY/CB SEP 14