Small Craft Advisory 337, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
615 AM ADT TUE APR 15 2008

.ANALYSIS AND UPPER LEVELS...
LONG WAVE POSITIVELY TILTED TROF THE MAIN FOCUS OF TODAYS WEATHER.
THE TROF AXIS IS FROM NE ALASKA THROUGH THE CENTRAL ALEUTIANS. THE
COLD FRONT IS LOCATED ALONG THE ALASKA RANGE AND THE ALASKA
PENINSULA. A MUCH STRONGER PUSH OF COLD AIR IS LAGGING BUT IS MAKING
ITS PRESENCE KNOWN IN THE KUSKOKWIM DELTA AND OVER THE CENTRAL BERING
SEA WHERE TEMPERATURES ARE DROPPING INTO THE SINGLE DIGITS AND WINDS
ARE GUSTING FROM THE NORTH AT 25 TO 45 MPH. HIGH PRESSURE IS BUILDING
OVER THE WESTERN BERING SEA.

.MODEL DISCUSSION...
MODELS CONTINUE TO BE CONSISTENT AND IN AGREEMENT WITH EACH OTHER.
NUMEROUS CONSECUTIVE RUNS SHOWING A VERY SIMILAR OUTLOOK WITH ONLY
MINOR DIFFERENCES IN TIMING OF THE FROPA. UNLIKE YESTERDAY...AM NOT
SEEING ANY INITIALIZATION PROBLEMS SO CONFIDENCE IS HIGH GIVEN THE
MODEL PERFORMANCE AND CURRENT SURFACE ANALYSIS.

.SHORT TERM FORECAST...
SOUTH AND EAST OF THE ALASKA RANGE...
FORECAST CHALLENGE CONTINUES TO BE TIMING AND STRENGTH OF THE COLD
FRONT PASSING THROUGH SOUTHCENTRAL TODAY AND THE PRECIPITATION
ASSOCIATED WITH THE FRONTAL PASSAGE AND SUBSEQUENT COLD AIR
ADVECTION. RADAR ECHOES INCREASING OVER THE NORTHERN GULF AS WELL AS
THE MATANUSKA AND SUSITNA VALLEYS. STILL THINKING PRECIPITATION OVER
THE ANCHORAGE BOWL WILL BE LIMITED. MAIN PRECIP FIELD WILL BE TO THE
EAST INCLUDING THE NORTHEASTERN GULF AND THE COPPER RIVER BASIN.
LARGE SCALE LIFT AND A DECENT FETCH OF MOISTURE WILL ENSURE THESE
AREAS SEE WIDESPREAD RAIN AND SNOW...CHANGING TO ALL SNOW OVERNIGHT
AS THE FRONT PASSES. AREAS IN THE COPPER RIVER BASIN SHOULD SEE THE
MOST SIGNIFICANT SNOW...THE FORECAST STAYS BELOW ADVISORY CRITERIA
BUT WILL HAVE TO WATCH THE OBSERVATIONS CLOSELY TODAY.

BESIDES THE COLDER TEMPERATURES FILTERING DOWN AND THE AREAS OF
SNOW...THE GAP WINDS WILL BE THE BIGGEST CONCERN BEGINNING TONIGHT.
STORM FORCE WINDS THROUGH THE BARREN ISLANDS ARE LIKELY WITH STRONGER
GUSTS POSSIBLE. PASSAGE CANAL AND RESURRECTION BAY WILL ALSO SEE
STRONG GALES AS THE COLD ADVECTION TEAMS UP WITH UPPER LEVEL SUPPORT
IN THE FORM OF THE POLAR JET. STORM FORCE GUSTS ARE NOT OUT OF THE
QUESTION FOR THESE AREAS.

HIGH PRESSURE BUILDS OVER SOUTHCENTRAL BY LATER IN THE WEEK AND
USHERS IN MORE SEASONAL TEMPERATURES. WHATEVER SNOW FALLS IN THE NEXT
36 HOURS WILL QUICKLY MELT AS IT APPEARS WINTER MAY BE ON ITS WAY OUT
AND SPRING CAN FINALLY BEGIN. BY THE WEEKEND...BROAD SOUTHERLY FLOW
AT ALL LEVELS WILL BRING 40 DEGREE WEATHER TO MOST OF SOUTHCENTRAL
AND 50S WITHIN REACH FOR MANY AREAS. EXTENDED MODELS HAVE BEEN PRETTY
CONSISTENT WITH THE HIGH AMPLITUDE RIDGE MOVING OVER EASTERN ALASKA
BY THE WEEKEND SO HAVE BEEN TRENDING TEMPERATURES IN THE EXTENDED
FORECAST IN THAT DIRECTION AS CONFIDENCE GROWS.

SOUTHWEST MAINLAND AND BERING SEA FORECAST...
STRONG WINDS COUPLED WITH SNOW SHOWERS BROUGHT BLIZZARD CONDITIONS TO
THE PRIBILOFS OVERNIGHT FOR SEVERAL HOURS. CONDITIONS HAVE ALREADY
IMPROVED BUT WILL HAVE TO WATCH FOR SIMILAR CONDITIONS NEAR COLD BAY
AS THE COLD AIR AND STRONG WINDS ARRIVE LATER THIS MORNING.
OTHERWISE...RELATIVELY STRAIGHT FORWARD FORECAST OUT WEST WITH A
DRYING TREND AND COOLER TEMPERATURES BEHIND THE COLD FRONT. SNOW
ALONG THE ALASKA PENINSULA THIS MORNING WILL TAPER OFF TO SNOW
SHOWERS AND QUICKLY END BY THIS EVENING. A SHORT WAVE WILL BRING
ANOTHER CHANCE OF SNOW TO THE KUSKOKWIM VALLEY WEDNESDAY WHILE HIGH
PRESSURE BUILDS OVER THE CENTRAL AND EASTERN BERING SEA. THE NEXT
STORM FORCE FRONT WILL PUSH ACROSS THE WESTERN ALEUTIANS WEDNESDAY
AND WEAKEN AS IT APPROACHES THE CENTRAL AND EASTERN ALEUTIANS BY THE
WEEKEND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM 130 176
         GALE 120 121 129 132 138 141 150 155 165 170 172 175 179
         HEAVY FREEZING SPRAY 130 141 179.
FIRE WEATHER...NONE.

AB APR 08