Small Craft Advisory 1032, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AST SAT DEC 8 2007

.MODEL DISCUSSION...THE MODELS ARE DOING A GOOD JOB GIVEN HOW
DYNAMICALLY ACTIVE THE CURRENT WEATHER PATTERN IS. IN THE GULF OF
ALASKA AREA THE MODELS ALL BRING A MODERATE LOW TOWARD KODIAK ISLAND
SUNDAY NIGHT. THE GFS AND ECMWF MODELS ARE IN ALMOST TOTAL AGREEMENT
WITH THE LOW SOUTHEAST OF KODIAK WHILE THE NAM WANTS TO PLACE IT JUST
SOUTH OF THE ISLAND. THIS GENERAL PATTERN CONTINUES WITH THE NAM
PLACING THE LOW A LITTLE TO THE WEST OF THE OTHER TWO MODELS AS IT
MOVES TOWARD AND OVER THE KENAI PENINSULA. THE ECMWF CAN BE USED
THROUGH 00Z MON TUESDAY AFTER WHICH PINT IT SHOULD BE VIEWED
CRITICALLY SINCE IT HAS THE LOW MAKING A SHARP RIGHT HAND TURN TO GO
SOUTHEAST OF MIDDLETON ISLAND WHILE THE GFS BRINGS THE LOW UP THE
EASTERN KENAI PENINSULA WITH THE NAM FARTHER WEST. THERE IS NO REASON
FOR THE LOW TO BEHAVE IN SUCH A MANNER SO THE GFS AND NAM SOLUTIONS
SEEM MORE REASONABLE. THE GFS IS THE PREFERRED SOLUTION IN LARGE PART
TO THE RUN TO RUN CONSISTENCY IT HAS HAD WITH THIS SYSTEM THE PAST
THREE TO FOUR RUNS.
IN THE BERING SEA REGION THE MODELS ARE FAIRLY CLOSE BUT HAVE SOME
DIFFERENCES IN HOW FAST EACH ONE WANTS TO MOVE THE LOW MOVING INTO
THE BERING SEA FROM THE SOUTH ON SUNDAY. GFS REMAIN THE PREFERRED
SOLUTION OUT WEST AS WELL WITH GOOD CONSISTENCY THE PAST FEW RUNS.
THE ONLY CONCERN IS THAT IT MAY BE MOVING THE LOW A LITTLE FAST PAST
60 HOURS OUT BUT THIS WILL NOT HAVE A LARGE IMPACT ON MOST OF THE
FORECAST AREA.

.ANALYSIS AND UPPER LEVELS...MAIN LOW CENTER IS IN THE BERING SEA
NORTH OF THE PRIBILOF ISLANDS. THE OLD FRONT EXTENDING OFF THIS LOW
STRETCHES INTO THE BRISTOL BAY AREA THIS AFTERNOON WHERE IT IS
BRINGING RAIN AND SNOW. THE UPPER LEVEL SUPPORT WITH THIS SYSTEM HAS
MOVED FARTHER EAST AND IS VISIBLE ON SATELLITE EXTENDING OUT OF THE
NORTH PACIFIC AND OVER THE CORDOVA AREA. A TRIPLE POINT LOW HAS
DEVELOPED ALONG THE NORTH GULF COAST BUT WILL NOT GAIN MUCH STRENGTH
BECAUSE THE UPPER LEVEL SUPPORT WILL CONTINUE TO THE EAST WHILE THE
LOW WEAKENS AND HEADS UP PRINCE WILLIAM SOUND THIS EVENING BEFORE
DISSIPATING EARLY SUNDAY MORNING.
IN THE BERING SEA THE LOW THAT IS NORTH OF THE PRIBILOFS WILL WEAKEN
AS IT MOVES NORTHWEST AS ANOTHER LOW SOUTH OF THE CENTRAL ALEUTIANS
WILL REPLACE IT IN THE EAST CENTRAL BERING SEA SUNDAY.

.SHORT TERM FORECAST...STARTING OFF IN THE ANCHORAGE AREA...WHERE ONE
HAS BEEN UNABLE TO PURCHASE A SNOWFLAKE AS OF LATE...LIGHT SNOW IS
EXPECTED OVERNIGHT WITH THE WEAK LOW MOVING INTO PRINCE WILLIAM
SOUND. WHILE THE FAVORABLE POSITION OF THE LOW WILL PROBABLY CAUSE
SOME SNOW IT SHOULD REMAIN LIGHT DUE TO A NUMBER OF OTHER UNFAVORABLE
CONDITIONS IN ASSOCIATION WITH IT...THE LARGEST BEING THE LACK OF
COLD AIR. WITH A LOW IN THE SOUND ONE WOULD LIKE TO SEE SOME GOOD
THERMAL PACKING AT 850 MB AND IT IS JUST NOT THERE. THIS ALONE WILL
LIMIT THE AMOUNT OF SNOW THAT MAY FALL. ALSO THERE IS NOW ENOUGH WARM
AR IN THE COOK INLET AND PRINCE WILLIAM SOUND AREA IT IS NOT A
GUARANTEE THAT PRECIPITATION WILL EVEN BE SNOW AT THIS POINT...THOUGH
IT DOES LOOK LIKE IT WILL COOL OFF ENOUGH FOR IT TO BE AT THIS POINT.
THE PRINCE WILLIAM SOUND AREA WILL SEE MOSTLY RAIN WITH THIS SYSTEM
WITH JUST TOO MUCH WARM AIR TO DEVELOP SNOW. THE EXCEPTION WILL BE AT
HIGHER ELEVATIONS AND IN VALDEZ WHERE COLD AIR CAN BE TAPPED FROM THE
COPPER RIVER BASIN.
BRISTOL BAY WILL ALSO SEE RAIN AND SNOW WITH WARM ADVECTION MOVING IN
FROM THE SOUTH OVERNIGHT.

.LONG TERM FORECAST...THERE WILL BE A SMALL PATTERN SHIFT IN THE
MIDDLE OF NEXT WEEK WHICH LOOKS TO START SENDING THE LOWS AROUND THE
ALEUTIAN ISLANDS INTO THE GULF AS OPPOSED THE BERING SEA IN THE
MIDDLE TO LATE PART OF NEXT WEEK. THE OVERALL UPPER LEVEL PATTERN
DOES NOT CHANGE MUCH HOWEVER SO THIS PATTERN OF BRINGING IN WARM AIR
AND FROM THE SOUTH WILL CONTINUE FOR AWHILE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 120 125 130 132 138 140 141 150 155 160 165 170 172 175
180 185.
FIRE WEATHER...NONE.

EZ DEC 07