Small Craft Advisory 726, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKDT FRI SEP 20 2013

.MODEL DISCUSSION...
MODELS ARE IN GENERALLY GOOD AGREEMENT ON THE SYNOPTIC FEATURES
THROUGH THE SHORT TERM. THOUGH THE PLACEMENT OF THE STORM MOVING INTO
THE GULF IS A LITTLE DIFFERENT...THE GENERAL IMPACT WITH WINDS AND
QPF ARE SOMEWHAT SIMILAR. THE GFS WITH SOME ADJUSTMENT IS PREFERRED.

.UPPER LEVELS...
THE STACKED LOW OVER THE NORTHERN PANHANDLE IS MOVING NORTH AND
WEAKENING. A WEAK TROUGH IS MOVING ACROSS SOUTHCENTRAL THIS AFTERNOON
AND MAY KICK OFF A FEW SNOW SHOWERS OVER THE COPPER RIVER BASIN. A
STRONG VORTEX IS EVIDENT MOVING RAPIDLY EAST ACROSS THE SE BERING
SEA. A STRONG SWLY JET IS EVIDENT SOUTH OF THE CENTER THE JUST SOUTH
OF ALEUTIANS AND AK PEN.

THE CENTER OVER THE EASTERN BERING SEA MOVES OVER THE SW GULF TONIGHT
AND TO THE SE GULF LATE SAT EARLY SUN MORNING. A SECONDARY TROUGH
MOVES SOUTH ACROSS TO EASTERN BERING SEA/BRISTOL BAY SAT EVENING TO
SOUTH OF THE AK PEN EARLY SUN MORNING. A STRONG NW JET IS EVIDENT ON
ITS WEST PERIPHERY.

.SHORT TERM FORECAST...
.SOUTHCENTRAL ALASKA...
WITH THE EXCEPTION OF MOSTLY CLOUDY CONDITIONS OVER THE COPPER
RIVER...FAIR SKIES WERE EVIDENT ACROSS THE REGION. GUSTY W TO NW
WINDS WERE EVIDENT ACROSS THE NORTHERN GULF WITH BRISK GAP WINDS OVER
THE NORTH GULF AND KENAI PEN.
THE DEVELOPING CENTER APPROACHING THE EASTERN ALEUTIANS THIS
AFTERNOON WILL MOVE OVER THE SOUTHERN GULF ON SAT AND TO THE SE GULF
ON SUN WITH A CENTRAL PRESSURE IN THE 960S. THE ASSOCIATED FRONT
MOVES TO THE WESTERN GULF THIS EVENING AND TO THE EASTERN AND NORTH
GULF ON SAT. GALE TO STORM FORCE WINDS ARE EXPECTED AHEAD OF THE
FRONT. WINDS ACROSS THE WESTERN GULF BECOME NWLY SAT AND INTENSIFY
SOME SAT NIGHT INTO SUN AS COLD AIR SPILLS IN THE WEST GULF. RAIN
SHOULD SPREAD TO KODIAK ISLAND THIS EVENING AND TO THE NORTH GULF ON
SAT. THE CURRENT LOW TRACK WOULD SUGGEST THAT THE MAJORITY OF
PRECIPITATION SHOULD REMAIN OVER THE GULF AND COASTS THROUGH SAT.
THINGS GET A LITTLE MORE INTERESTING SUN NIGHT AND MON AS THE GFS
SHOWS A DEFORMATION AXIS SETTING UP ACROSS THE EASTERN KENAI AND
ANCHORAGE BOWL/MATSU AND WEAK COLD ADVECTION. THE NAM HOWEVER IS FAR
LESS AGGRESSIVE WITH THE DEFORMATION POTENTIAL AND QPF. BOTTOM
LINE...THERE IS SOME POTENTIAL FOR SNOW OR A MIX SUN NIGHT INTO MON
ACROSS THE ANCHORAGE BOWL AND MAT VALLEY.

.SW ALASKA INCLUDING AK PEN...
RADAR SHOWS RAIN STARTING TO IMPACT COASTAL SW ALASKA THIS AFTERNOON.
OBSERVATIONS INDICATE RAIN IS SPREADING ACROSS THE AK PEN. STRONG SE
WINDS ARE EVIDENT OVER THE AK PEN AND ARE SPREADING TO THE SW COAST.
WINDS WILL BECOME WESTERLY ACROSS THE AK PEN THIS EVENING AND NW
OVERNIGHT. WINDS WILL BE FAIRLY STRONG WITH GALE TO STORM FORCE
GUSTS. WINDS ACROSS THE AK PEN WILL INCREASE SAT EVENING AS AN UPPER
WAVE DROPS SOUTH ACROSS THE AREA AND COLD ADVECTION SPILLS SOUTH
ACROSS THE BERING SEA. WINDS AT THIS TIME MAY HIT HIGH WARNING LEVELS
WITH COULD HOLD INTO SUN MORNING. WINDS WILL BECOME NORTHERLY OVER
THE SW MAINLAND AND BE CONSIDERABLY LIGHTER. RAIN OVER THE AK PEN AND
SW MAINLAND WILL GIVE WAY TO SHOWERS WILL DRYING SPREADING SOUTH
ACROSS THE MAINLAND SAT.

.BERING SEA/ALEUTIANS...
WESTERLY/NWLY GALE TO STORM FORCE WINDS ARE SPREADING EAST ACROSS THE
REGION IN THE WAKE OF THE DEVELOPING LOW CENTER. WINDS ARE EXPECTED
TO PEAK NEAR WARNING LEVELS THIS EVENING OVER UNALASKA...BUT WILL
REMAIN STRONG THROUGH SAT AFTERNOON. WINDS ACROSS THE CENTRAL
ALEUTIANS/BERING SEA WILL DIMINISH THROUGH SAT THEN INCREASE OUT OF
THE S-SE OVER THE WESTERN PORTION SAT EVENING WITH THE APPROACH OF A
FRONTAL TROUGH.

.LONG TERM FORECAST...
FOR NEXT WEEK A SHORTWAVE TROUGH WILL BE POSITIVE TILTED THROUGH THE
BERING SEA AS A CUTOFF LOW FORMS OVER THE WESTERN ALEUTIANS. THERE
WILL BE A STRONG MERIDIONAL JET STREAK OVER THE CENTRAL ALEUTIANS
WITH A AMPLIFIED RIDGE OVER THE EASTERN ALEUTIANS WHICH WILL
GRADUALLY MOVE EASTWARD. THIS WEATHER PATTERN WILL ALLOW STORMS TO
KEEP TRACKING THROUGH THE BERING SEA BEFORE CROSSING INTO THE GULF OF
ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 185. HIGH WIND WATCH 181.
MARINE...STORM WARNING 120 132 150 155 170.
         GALE WARNING 130 136 137 138 140 172 160 165 176 180.
FIRE WEATHER...NONE.

RMC SEP 13