Small Craft Advisory 211, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT SUN MAR 9 2008

.MODEL DISCUSSION AND UPPER LEVELS...
MODELS IN GOOD AGREEMENT THROUGH WEDNESDAY. THE BIGGEST DIFFERENCE IN
THE SHORT TERM IS THE POSITION OF THE LOW IN THE NORTHWEST GULF. THE
ECMWF HAS THE LOW TOO FAR EAST. ALL MODELS PULL THIS STACKED LOW TO
THE GALENA AREA MONDAY TOWARD THE MEAN UPPER TROUGH IN THE EASTERN
BERING. THIS IS DUE TO THE LOW LOSING ITS UPPER LEVEL SUPPORT WHICH
DROVE IT NORTH YESTERDAY. BY TUESDAY A BROAD WEAK LOW TO BE OVER THE
MAINLAND AS THE UPPER LOW HAS NOW DISSIPATED TO AN OPEN WAVE. THE LOW
TO DISSIPATE WEDNESDAY AS AN UPPER RIDGE MOVES OVER THE MAINLAND.
MEANWHILE...OUT OVER THE BERING...THE MEAN TROUGH IS POSITIONED OVER
THE EASTERN BERING WITH AN UPPER LOW NEAR SAINT PAUL. A WEAK SURFACE
TROUGH OVER THE EASTERN BERING CONCENTRATING SOME SHOWER ACTIVITY.
THIS TO LEAVE THE AREA TOMORROW AS HIGH PRESSURE MOVES OVER THE AREA.

A FRONT WILL MOVE TO THE WESTERN ALEUTIANS MONDAY NIGHT AND STALL
WEST OF ADAK TUESDAY AWAITING THE NEXT LOW WHICH PUSHES THE FRONT
NEAR THE PRIBILOF ISLANDS THURSDAY. THIS LOW TO DISSIPATE AS A
STRONGER SOUTHERN LOW TAKES OVER. THIS IS WHERE THE DISCREPANCIES
START TO SHOW WITH THE MODELS. THE 12Z GFS AND ECMWF MUCH FASTER WITH
THIS LOW MOVING INTO THE BERING FRIDAY NIGHT. THE PREVIOUS RUNS OF
BOTH MODELS KEPT IT SOUTH OF CHAIN THROUGH SATURDAY. STUCK WITH OLDER
SOLUTIONS DUE TO THE FACT THIS LOW IS PUSHING INTO LONG WAVE RIDGE.
MEANWHILE ANOTHER LOW HAS MOVED ACROSS THE NORTHERN PACIFIC AND THEN
EAST ACROSS JUST SOUTH OF THE GULF THURSDAY THROUGH THURSDAY.

THE MEAN TROUGH IS CURRENTLY OVER THE EASTERN BERING AND WILL WEAKEN
OVER THE NEXT COUPLE DAYS AS A COUPLE WEAK SHORT WAVES MOVE OUT OF
THIS REGION. IN ADDITION...A STRONG LOW STARTS TO DEVELOP NEAR THE
KAMCHATKA PENINSULA. AS A RESULT...THE MEAN TROUGH POSITION WILL
RETROGRADE TO THE WESTERN BERING BY MID WEEK THEN DEEPEN LATER IN THE
WEEK.

.ANALYSIS...
A LOW NEAR KODIAK ISLAND BRINGING STRONG WINDS TO SOUTH CENTRAL AND
ASSOCIATED MARINE AREAS. GOOD AMOUNT OF PRECIPITATION HITTING THE
COASTAL LOCATIONS. GAP WINDS WILL INCREASE TONIGHT AS THE LOW LIFTS
NORTH. ANOTHER LOW NEAR THE PRIBILOFS CREATING AN AREAS OF MODERATE
NORTH TO NORTHEAST WINDS FROM BRISTOL BAY TO THE PRIBILOFS. IN
ADDITION...MODERATE SNOW SHOWERS STREAMING THROUGH THE CENTRAL AND
EASTERN ALEUTIANS INTO THE ALASKA PENINSULA. WINDS AND SNOW SHOWERS
ALONG THE KUSKOKWIM DELTA COAST MAKING FOR BLIZZARD CONDITIONS THERE.
THESE CONDITIONS TO LIKELY REMAIN THROUGH THIS EVENING WHEN THE LOW
NEAR THE PRIBILOFS DROPS TO THE CHAIN.

.SHORT TERM FORECAST...
ALEUTIANS AND BERING...
LOW PRESSURE TROUGH FROM THE CENTRAL BERING TO THE BRISTOL BAY.
MODERATE WINDS AND SNOW SHOWERS IN THE CENTRAL AND EASTERN BERING.
SOME SHOWERS HAVE DROPPED VISIBILITIES TO LESS THAN A MILE AT TIMES.
THE TROUGH TO DISSIPATE TONIGHT AND TOMORROW AS HIGH PRESSURE BUILDS
OVER THE CENTRAL AND EASTERN BERING. SHOWERS SHOULD DIMINISH THROUGH
THIS PERIOD. MEANWHILE...A FRONT TO MOVE TO SHEMYA MONDAY NIGHT WITH
GALE FORCE WINDS. THE FRONT WILL SLOWLY MOVE TO NEAR ADAK TUESDAY
NIGHT. ANOTHER LOW MOVING OUT OF THE NORTH PACIFIC TO PUSH THE FRONT
NORTH AND EAST WEDNESDAY. THIS LOW TO WRAP NEAR ADAK WEDNESDAY NIGHT
AND STALL WITH GALE FORCE WINDS.

WESTERN ALASKA...
LOW NEAR KODIAK AND SAINT PAUL WITH SNOW SHOWERS THROUGHOUT EXCEPT IN
THE KUSKOKWIM VALLEY. MODERATE WINDS ALONG THE KUSKOKWIM DELTA COAST
COMBINED WITH THESE SHOWERS PRODUCING LOCALIZED BLIZZARD CONDITIONS.
THE CONDITIONS TO GRADUALLY DECREASE TONIGHT INTO TOMORROW AS TROUGH
OF LOW PRESSURE OVER THE EASTERN BERING DISSIPATES. HOWEVER...SHOWERS
SHOULD CONTINUE OVER WESTERN ALASKA AS THE LOW NEAR KODIAK SLIPS UP
TO GALENA TOMORROW AND REMAINS IN THE GENERAL AREA THROUGH TUESDAY.
HIGH PRESSURE TAKES OVER TUESDAY NIGHT.

SOUTH CENTRAL...
LOW NEAR KODIAK WITH STRONG FRONT ALONG THE NORTHERN GULF COAST.
MODERATE TO STRONG WINDS THROUGH PRINCE WILLIAM SOUND AS WELL. EAST
WEST GAP WINDS TO INCREASE THIS EVENING ALONG TURNAGAIN ARM AS THE
LOW RIDES NORTH AND WEST TOWARD ILIAMNA. ALSO SEEING STRONG WEST
WINDS ON THE BACK SIDE OF THE LOW. THE AIR MASS WILL GET COLDER AS
THE STACKED SURFACE LOW MOVES NORTH. THIS WILL ALSO TURN PRECIP TO
SNOW AND MORE STEADY IN THE VALDEZ AREA. IN ADDITION...SOME SHOWERS
TO SPILL TO INLAND CONDITIONS. THEREFORE...HAVE ADDED SOME SHOWERS TO
THE ANCHORAGE AND PALMER AREAS LATE TONIGHT AND EARLY TOMORROW. THE
LOW MOVES WELL INLAND TOMORROW AFTERNOON NEAR GALENA AND WEAKENS
CONSIDERABLY. AS A RESULT...THE PRECIPITATION WILL BE A BIT MORE
WIDESPREAD BUT LESS INTENSE FOR MOST AREAS BY TOMORROW EVENING. WINDS
WILL DIMINISH TONIGHT INTO TOMORROW AS WELL. SHOWERS TO REMAIN IN THE
AREA INTO TUESDAY...BUT HIGH PRESSURE RULES THE DAY BY WEDNESDAY. A
LOW MOVING SOUTH OF THE GULF WILL INCREASE WINDS IN THE SOUTHERN GULF
WEDNESDAY.

.LONG TERM FORECAST...
AS MENTIONED EARLIER...BELIEVE THE 00Z GFS/ECMWF SOLUTIONS MORE WITH
A SLOWER PROGRESSION OF THE NORTH PACIFIC LOW NORTH THURSDAY THROUGH
SUNDAY. OVERALL...VERY STRONG WINDS TO REACH THE ALEUTIANS WITH THIS
CONSOLIDATED LOW WEDNESDAY THROUGH FRIDAY. MEANWHILE ANOTHER LOW HAS
MOVED ACROSS THE NORTHERN PACIFIC AND THEN EAST ACROSS JUST SOUTH OF
THE GULF THURSDAY THROUGH THURSDAY LEAVING A TROUGH OF LOW PRESSURE
ALONG THE COAST THROUGH SATURDAY. THEN EVEN SOUTH CENTRAL ALASKA
COMES UNDER THE INFLUENCE OF THE BERING LOW.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...BLIZZARD WARNING ZONE 155
MARINE...GALE 120 125
         HEAVY FREEZING SPRAY 179 185
FIRE WEATHER...NONE

JN MAR 08