Brisk Wind Advisory 66, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
300 PM AKST TUE DEC 22 2009

.MODEL DISCUSSION...THE MODELS SEEM A BIT IMPROVED OVER PAST DAYS AND
ARE NOW COLLUDING TO BRING THE DEVELOPING LOW IN THE GULF ONTO THE
EASTERN KENAI PENINSULA BEFORE RAPIDLY DISSIPATING IT WEDNESDAY
EVENING. THE NAM TRACK SHOWS A LITTLE MORE DETAIL WITH IT HEADING
INTO SOUTHWEST PRINCE WILLIAM SOUND AS IT DISSIPATES WEDNESDAY
EVENING AND HAS WHAT LOOKS LIKE THE BEST SOLUTION AT THIS TIME. THE
LARGE LOW SOUTH OF THE ALASKA PENINSULA WEDNESDAY THROUGH FRIDAY
SEEMS TO BE HANDLED WELL BY ALL OF THE MODELS.

.ANALYSIS AND UPPER LEVELS...A STRONG 180 KT PLUS JET STREAM REMAINS
SOUTH OF THE FORECAST AREA RUNNING DUE EAST ALONG THE 40N PARALLEL.
THIS JET IS SPAWNING A LOW THAT WILL BE IN THE LOWER 960S BY
WEDNESDAY MORNING ABOUT 600 MILES SOUTH OF THE ALASKA PENINSULA.

A JET STREAK RUNS THROUGH THE EAST CENTRAL GULF OF ALASKA IN
CONJUNCTION WITH A DEVELOPING LOW THAT WILL MOVE INTO THE NORTH GULF
COAST WEDNESDAY. THIS LOW IS A TRICKY FEATURE THAT WILL HAVE A LARGE
IMPACT FOR MOST OF SOUTH CENTRAL ALASKA. SMALL DEVIATIONS IN THE LOW
TRACK WILL HAVE A LARGE IMPACT ON WINDS...PRECIPITATION...AND
PRECIPITATION TYPE LATE TONIGHT THROUGH WEDNESDAY EVENING.

.SHORT TERM FORECAST...THE WESTERN PART OF THE FORECAST AREA IS
RELATIVELY STRAIGHTFORWARD WITH A WEAK LOW MOVING ACROSS THE ALASKA
PENINSULA AND INTO THE EASTERN BERING SEA/SOUTHWEST ALASKA AREA. THIS
LOW WILL BRING RAIN AND SNOW SHOWERS WHICH WILL TURN TO MOSTLY SNOW
SHOWERS OVERNIGHT AS COOLER AIR FROM THE WEST FILTERS IN.

AS MENTIONED ABOVE THE DIFFICULT CALLS ARE WITH THE LOW MOVING INTO
THE NORTH GULF COAST. THE CURRENT ANTICIPATED TRACK WILL BRING STRONG
WINDS INTO THE CORDOVA AREA AND PRINCE WILLIAM SOUND. THERE IS A
POSSIBILITY THE THE CORDOVA AREA COULD EVEN REACH HIGH WIND WARNING
CRITERIA AS THE GRADIENT EARLY TOMORROW MORNING BUT THE UNCERTAINTY
OF THE TRACK IS ENOUGH TO WAIT TO SEE THE STRENGTH OF THE LOW AND
ACTUAL TRACK DEVELOP MORE BEFORE DECIDING WHETHER THAT IS LIKELY
ENOUGH TO ISSUE A WARNING. RAIN WILL MOVE INTO THE CORDOVA AREA AND
EASTERN KENAI PENINSULA. VALDEZ WILL LIKELY MIX RAIN INTO THE
PRECIPITATION BUT IT COULD GO EITHER WAY...REMAINING ALL SNOW OR
TURNING TO ALL RAIN. SNOW WILL LIKELY BE TOO WET AND HEAVY TO CAUSE
TRUE BLIZZARD CONDITIONS IN THOMPSON PASS...BUT IT WILL BE WORTH
WATCHING AS THE SYSTEM CONTINUES TO DEVELOP.
THERE IS A CHANCE OF FREEZING RAIN INTO THE ANCHORAGE AND MAT-SU
AREAS WITH INCREASED LOW LEVEL NORTHEAST FLOW COMBINED WITH WARMER
AIR RIDING OVER ALOFT. THE KEY WILL BE WHETHER THE LOW MOVES FAR
ENOUGH WEST BEFORE DISSIPATING.

.LONG TERM FORECAST...MODELS SHOW LITTLE CHANGE IN THE LARGE-SCALE
WEATHER PATTERN OVER THE NEXT WEEK. RIDGING TO THE EAST WILL KEEP
WARM AND MOIST SOUTHERLY FLOW STREAMING INTO THE MAINLAND...AND THE
PRIMARY STORM TRACK WILL CONTINUE TO BRING LOWS UP INTO THE GULF AND
THEN CURVE NORTHWEST INTO SOUTHWEST ALASKA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 129 130 132 138 140 150 160 165 170.
         STORM 120 125.
FIRE WEATHER...NONE.

DEC 09