Small Craft Advisory 211, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AST TUE FEB 27 2007

.DISCUSSION...
NCEP MODELS INITIALIZED MOISTURE OK THIS MORNING. IN
ADDITION...EUROPEAN AND NCEP MODELS HAVE INITIALIZED PRESSURE CENTERS
WELL THIS MORNING. ALL NCEP AND EUROPEAN MODELS ALSO HANDLE THE
PATTERN SIMILAR THROUGH THE WEEK. THE BIG DIFFERENCES APPEAR TO BE IN
THE GULF WITH THE PROGRESSION OF A LOW WEDNESDAY. LEANING TO THE GFS
SOLUTION AS THE COLD AIR PUSHING DOWN AND JET TO THE SOUTH WILL
LIKELY PULL THE LOW EASTWARD CLOSER TO THE GFS SOLUTION. UKMET LEAVES
A DEEP LOW IN THE CENTRAL GULF WHILE THE NAM IS JUST NOT AS FAST AS
THE GFS.

UPPER LEVELS...ONCE AGAIN TROUGHS TO REMAIN OVER EASTERN ALASKA
THROUGH THE PANHANDLE AND NEAR KAMCHATKA WITH A RIDGE OVER THE BERING
SEA THROUGH THE WEEK. THE RIDGE OVER THE BERING WEAKENED TODAY DUE TO
A FRONT MOVING THROUGH. THE RIDGE WILL POP BACK WEDNESDAY WITH A LOW
DEVELOPING SOUTH OF THE ALEUTIAN CHAIN. THE TROUGH OVER THE MAINLANDS
AND PANHANDLE TO INTENSIFY WEDNESDAY NIGHT WITH ANOTHER SHOT OF COLD
AIR. THE LOW SOUTH OF THE ALEUTIANS TO FEED INTO THE GULF OF ALASKA
TROUGH FRIDAY. WITH A MORE AMPLIFIED TROUGH NEAR 165E BY FRIDAY...THE
RIDGE OVER THE BERING WILL STRETCH FROM 30N TO 80N ALONG 175W. THE
RIDGE WILL EXTEND INTO THE MAINLAND OVER THE WEEKEND THEN RETROGRADE
EARLY NEXT WEEK AS ANOTHER SHOT OF COLD AIR DIGS THE TROUGH OVER
EASTERN ALASKA AND PANHANDLE FARTHER WEST. THE RIDGE WILL CONTINUE TO
RETROGRADE THROUGH MID NEXT WEEK.

SURFACE EAST OF THE ALASKA RANGE...TEMPERATURES NOT AS COLD OR WINDS
AS STRONG SINCE RIDGE HAS BECOME LESS AMPLIFIED AND MODERATED
TEMPERATURES HAVE MOVED OVER THE MAINLAND A BIT. THE FRONT DRAPED
OVER THE BERING CURRENTLY TO SHEAR APART WITH A PIECE DEVELOPING A
LOW IN THE GULF WEDNESDAY. THIS WILL BRING A CHANCE OF PRECIPITATION
TO KODIAK. AS THE LOW DEEPENS OVER THE EASTERN GULF WEDNESDAY NIGHT
AND THURSDAY...ANY SHOWER ACTIVITY WILL END OVER KODIAK. ANOTHER SHOT
OF COLD AIR TO ARRIVE WEDNESDAY NIGHT. THIS WILL BRING SOME STRONG
WINDS TO NORTH SOUTH ORIENTED GAPS. WILL ISSUE HIGH WIND ADVISORY FOR
ALL OF ZONE 131 STARTING WEDNESDAY NIGHT AND CONTINUING THROUGH
FRIDAY. THROUGH THE COPPER RIVER DELTA...THE WINDS WILL BE A BIT
LATER WAITING FOR BETTER UPPER LEVEL SUPPORT AFTER THE UPPER LEVEL
DISTURBANCES PASSES OVERHEAD THURSDAY. THIS IS DUE TO THE STRONG
NORTHERLY FLOW TO CONTINUE OVER THE AREA FOR THAT LONG INCLUDING THE
FAVORABLE PRESSURE GRADIENT. THIS WILL ALSO MEAN STRONG WINDS FOR
MOST AREAS OF SOUTH CENTRAL AND THE GULF INTO FRIDAY. STRONG WINDS
THROUGH NORTH SOUTH GAPS MAY CONTINUE LONGER...BUT WARNING LEVEL
SHOULD BE OVER BY FRIDAY EVENING. OVERALL...CONTINUED WELL BELOW
NORMAL TEMPERATURES AND DRY CONDITIONS.

SURFACE WEST OF THE ALASKA RANGE...THE LOW PRESSURE SYSTEM WEST OF
SHEMYA DRIVING A FRONT ACROSS THE BERING SEA. MODERATE WINDS AND
PRECIPITATION ASSOCIATED WITH THIS FRONT. THE FRONT WILL WEAKEN IN
THE EASTERN BERING AND ALONG THE COAST THIS EVENING. THE FRONT WILL
EVENTUALLY SHEAR APART WEDNESDAY WITH HIGH PRESSURE AND COLDER
TEMPERATURES RETURNING TO SOUTHWEST ALASKA AND THE EASTERN BERING. IN
THE MEANTIME...ANOTHER LOW TO WORK TO THE WESTERN ALEUTIAN ISLANDS
WITH A STRONG FRONTAL BOUNDARY OVER THE BERING SEA TO THE EASTERN
ALEUTIANS. THIS BOUNDARY IS STRONGER DUE TO THE STRONG TEMPERATURE
GRADIENT BETWEEN THE COLD AIR TO THE NORTH AND WARMER AIR TO THE
SOUTH. THE WINDS AND PRECIPITATION THEREFORE WILL BE STRONGER AS A
RESULT. MORE HEAVY FREEZING SPRAY OUT OF THIS PATTERN AS WELL FROM
BRISTOL BAY TO SAINT MATTHEW ISLAND ACROSS THE PRIBILOF ISLANDS. EVEN
THOUGH THE LOW SLIDES EAST SOUTH OF THE ALEUTIAN CHAIN...THE BOUNDARY
TO REMAIN THROUGH THURSDAY EVENING. THEN...HIGH PRESSURE WILL BUILD
OVER THE ENTIRE BERING. ANY NEW LOW PRESSURE SYSTEM WILL RIDE NORTH
JUST WEST OF THE ALEUTIANS. HOWEVER...SOME PRECIPITATION AND WINDS
WILL BE PRESENT OVER THE EXTREME WESTERN ALEUTIANS AND BERING OVER
THE WEEKEND FROM ONE LOW.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WATCH WED NIGHT THRU FRI ZONE 131 AND 135
MARINE...GALE...155 165 170 171 179 185
         HEAVY FREEZING SPRAY...120 121 125 129 130 138 140 141
                                160 165 185
FIRE WEATHER...NONE

JN FEB 07