Small Craft Advisory 932, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
415 AM AKST TUE NOV 25 2008

.MODEL DISCUSSION...
A LOW SOUTH OF THE AK PENN THIS MORNING WILL TRACK INTO THE GULF
TODAY. MODEL SOLUTIONS DIVERGE WITH THIS TRACK. WILL GO WITH THE
ECMWF/NAM SOLUTION WHICH LINE UP WELL. EC HAS BEEN CONSISTENTLY
BETTER AT CATCHING THE DEVELOPING SURFACE LOWS. GFS WANTS TO TROUGH
THEM OUT TOO SOON AND PUSH THEM INLAND. MODELS REMAIN FAIRLY
CONSISTENT WITH DEVELOPMENT OF A 950S LOW SOUTH OF THE ALEUTIANS
WEDNESDAY. EXACT TRACK IS STILL IN QUESTION...BUT ALL SOLUTIONS ARE
GROUPED IN THE SAME GENERAL AREA AND THE END RESULT OF STORM FORCE
WINDS ALONG THE ALEUTIANS AND ALASKA PENINSULA IS THE SAME.

.ANALYSIS AND UPPER LEVELS...
WE CONTINUE TO BE IN A VERY PROGRESSIVE PATTERN. THERE ARE A NUMBER
OF LOWS AFFECTING THE SOUTHERN PART OF ALASKA THIS MORNING. THE FIRST
ONE IS CURRENTLY EAST OF KODIAK ISLAND MOVING TOWARD MIDDLETON
ISLAND. ITS ASSOCIATED FRONT IS PRODUCING RAIN AND SNOW SHOWERS
ACROSS THE SOUTHCENTRAL. A SECOND LOW IS STRENGTHENING SOUTH OF THE
AK PENN. THIS WILL BECOME MORE OF A PLAYER THIS AFTERNOON AS IT
ENTERS THE GULF AND PUSHES THE FIRST LOW INLAND WHERE IT WILL
DISSIPATE. AS THE LOW ENTERS THE GULF THE UPPER LEVEL TROUGH
CURRENTLY STRETCHING FROM THE SEWARD PENINSULA SOUTH ALONG THE
WESTERN COAST OF AK WILL PUSH INLAND INTO BRISTOL BAY. FOR THIS
MORNING THOUGH WEAK COLD ADVECTION DOMINATES THE BERING
SEA...PRODUCING A LOT OF STRATOCU AND SOME SNOW SHOWERS.

FARTHER WEST ANOTHER WEAK LOW CONTINUES TO SPIN NEAR ADAK BRINGING
SHOWERS ALONG THE CENTRAL AND EASTERN ALEUTIANS. THIS LOW WILL
EVENTUALLY BE ABSORBED INTO A DEVELOPING LOW IN THE NORTH PACIFIC
THIS EVENING. BY TOMORROW THE 980S NORTH PACIFIC LOWS OCCLUSION WILL
AFFECT THE GULF. BUT THE BIGGER CONCERN OUT WEST WILL BE THE 940S LOW
THAT WILL BE SOUTH OF THE CENTRAL ALEUTIANS TOMORROW.

.SHORT TERM FORECAST...
SOUTHCENTRAL..IT LOOKS LIKE THE FREEZE/THAW ALONG THE COAST WILL
CONTINUE OVER THE NEXT FEW DAYS AS ONE SYSTEM AFTER ANOTHER MOVES
TOWARD OR JUST SOUTH OF THE GULF. FOR TODAY EXPECT RAIN FROM KODIAK
TO CORDOVA WITH SNOW MIXING IN AT TIMES AT HIGHER ELEVATIONS. AS THE
TROUGH ALONG THE WEST COAST PUSHES EAST..THIS WILL PRODUCE LIFT
ACROSS WESTERN SOUTHCENTRAL. THERE IS DEFINITE POTENTIAL FOR A SHORT
PERIOD OF MODERATE SNOW FROM ANCHORAGE TO THE MAT-SU THIS EVENING
INTO WEDNESDAY. MEANWHILE...THE NEXT LOW WILL BE MOVING INTO THE GULF
WEDNESDAY WHICH WILL BRING ANOTHER CHANCE OF SNOW WEDNESDAY NIGHT.

SOUTHWEST AK..THE MODELS CONTINUE TO INDICATE LITTLE TO NO QPF AS THE
TROUGH SWINGS THROUGH TODAY. WITH ONSHORE FLOW AND A DECENT STRENGTH
TROUGH AXIS WILL GO WITH SCATTERED SNOW SHOWERS FOR THE DELTA AND
JUST ISOLATED SNOW SHOWERS AS IT MOVES INLAND. CONDITIONS WILL DRY
OUT ACROSS THE REGION BEHIND THIS TROUGH ON TUESDAY NIGHT AND
WEDNESDAY. COLD ADVECTION WILL ENSURE BEHIND THE FIRST TROUGH TONIGHT
AND TUESDAY. THUS...WITH THE EXCEPTION OF THE IMMEDIATE COAST WHERE
ONSHORE FLOW WILL KEEP TEMPS FROM DROPPING MUCH...THERE WILL BE A
COOLING TREND OVER THE REST OF SOUTHWEST ALASKA HEADING THROUGH THE
NEXT FEW DAYS.

ALEUTIANS AND BERING..THE LOW WILL TRACK SLOWLY SOUTHEASTWARD
CROSSING OVER THE ALEUTIANS NEAR ADAK EARLY THIS MORNING. BROAD WEAK
NORTHERLY FLOW BEHIND THIS LOW AND SURFACE TROUGH CURRENTLY ALONG THE
ALEUTIANS WILL MAINTAIN WEAK COLD ADVECTION THROUGH TUESDAY
NIGHT...RESULTING IN THE TYPICAL MOSTLY CLOUDY SKIES WITH SNOW
SHOWERS. A PACIFIC LOW WILL RAPIDLY DEEPEN MONDAY NIGHT THROUGH
WEDNESDAY...IN AN IDEAL POSITION BETWEEN TWO UPPER JETS. IT IS
UNCLEAR HOW CLOSE THE LOW WILL COME TO THE ALEUTIANS. CONDITIONS WILL
QUICKLY HEAD DOWNHILL LATE WEDNESDAY WITH WIDESPREAD STORM FORCE
WINDS EXPECTED BY WEDNESDAY NIGHT. RIGHT NOW IT LOOKS LIKE IT WILL BE
COLD ENOUGH FOR PRECIPITATION TO START AS SNOW AND THEN MIX WITH OR
CHANGE TO SNOW. WILL NEED TO WATCH THIS CLOSELY. IF LOW TRACK IS A
LITTLE FARTHER SOUTH PRECIPITATION COULD STAY ALL SNOW AND POTENTIAL
FOR BLIZZARD WOULD NEED TO BE CONSIDERED.

.LONG TERM FORECAST...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN ACTIVE THROUGH THIS WEEK.
THIS WILL RESULT IN A CONTINUING TRAIN OF LOWS MOVING THROUGH THE
FORECAST AREA ONE RIGHT AFTER THE OTHER. MODELS ARE INDICATING A VERY
STRONG LOW APPROACHING THE ALEUTIANS FROM THE NORTH PACIFIC. WILL
NEED TO WAIT AND SEE BUT COULD BE LOOKING AT A NUMBER OF WIND AND/OR
BLIZZARD WARNINGS COMING UP LATER IN THE WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...STORMS 172
         GALES  170 175 180
         HEAVY FREEZING SPRAY 130 180 185
FIRE WEATHER...NONE

RW NOV 08