Small Craft Advisory 754, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
200 PM AKDT SAT SEP 28 2013

.ANALYSIS AND UPPER LEVELS...
THERE IS AN UPPER LEVEL LOW OVER THE SOUTHEAST GULF OF ALASKA WITH A
TROUGH EXTENDING NORTHWEST INTO MAINLAND ALASKA. THERE IS A BROAD
UPPER LEVEL RIDGE OVER THE BERING SEA AND ALEUTIANS WITH FAIRLY
STRONG NORTHWESTERLY FLOW BETWEEN THESE TWO FEATURES.

.MODEL DISCUSSION...
THE NUMERICAL MODELS ARE IN REASONABLY GOOD AGREEMENT. THERE ARE
SOME TIMING/LOCATION DIFFERENCES WITH A LOW MOVING INTO THE BERING
SEA ON MONDAY...AND SOME MINOR DIFFERENCES ON THE HANDLING OF SMALL
SCALE FEATURES IN THE TROUGH OVER ALASKA. BUT OVER-ALL THE
DIFFERENCES ARE NOT THAT LARGE AND FORECAST CONFIDENCE IS HIGHER
THAN NORMAL THROUGH SUNDAY...THEN NEAR NORMAL FOR MONDAY AND
TUESDAY.

.SHORT TERM FORECAST...
FOR SOUTH CENTRAL ALASKA...THE UPPER LEVEL TROUGH WILL REMAIN OVER
ALASKA THROUGH TUESDAY AFTERNOON...THOUGH WEAKENING SOME ON TUESDAY.
OFFSHORE FLOW AT THE LOWER LEVELS WILL KEEP THE AREA FAIRLY DRY.
THERE MAY PERIODICALLY BE A SLIGHT CHANCE OF PRECIPITATION AS
VARIOUS WEAK VORTICITY CENTERS SPIN ABOUT...BUT IT WILL MOSTLY MEAN
THERE WILL BE SOME (MAINLY MID AND HIGH LEVEL) CLOUDS AROUND.

FOR SOUTHWEST ALASKA...A WEAK VORTICITY MAXIMUM AND/OR DEFORMATION
BAND ALONG AND NEAR THE ALASKA/ALEUTIAN RANGES WILL WEAKEN TONIGHT
BUT CONTINUE TO PROVIDE SOME PRECIPITATION. THIS "SYSTEM" WILL
CONTINUE TO WEAKEN THROUGH SUNDAY AND DISSIPATE SUNDAY NIGHT.
OTHERWISE SOUTHWEST ALASKA WILL BE MAINLY DRY...EXCEPT FOR A SYSTEM
SLIDING DOWN IN THE NORTHWESTERLY FLOW ALOFT MAY CLIP THE COASTAL
AREAS ON MONDAY.

FOR THE BERING SEA AND ALEUTIANS...HIGH PRESSURE ALOFT WILL KEEP
SIGNIFICANT WEATHER SYSTEMS OUT OF THE AREA THROUGH SUNDAY NIGHT
WHILE SLOWLY MOVING EAST. A LOW PRESSURE SYSTEM WILL MOVE INTO THE
WESTERN ALEUTIANS ON MONDAY...INTO THE CENTRAL ALEUTIANS/BERING
MONDAY NIGHT AND EASTERN ALEUTIANS/BERING ON TUESDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 130 132 136 137 138 150 155 160.
FIRE WEATHER...NONE.

LUDWIG SEP 13