Small Craft Advisory 466, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT SAT MAY 26 2007

.MODEL DISCUSSION...
MODELS IN GENERALLY GOOD AGREEMENT THROUGH 60 HOURS.

.UPPER LEVELS...
UPPER LEVELS CHARACTERIZED BY LONG WAVE RIDGE EXTENDING OUT OF
WESTERN CANADA AND ACROSS MAINLAND ALASKA. ELONGATED AREA OF REDUCED
HEIGHTS OVER THE EASTERN BERING SEA AND ALEUTIANS. AND BROAD ZONAL
FLOW BETWEEN 40N AND 50N. PATTERN SHIFTS SIGNIFICANTLY BY 60 HOURS.
A CUTOFF H540 LOW DEVELOPS NEAR 50N 150W CAUSING BROAD SOUTHERLY FLOW
ALOFT TO DEVELOP ACROSS THE GULF OF ALASKA AND SOUTHERN MAINLAND.

.SHORT TERM...
SURFACE RIDGE OF HIGH PRESSURE PERSISTS ALONG THE EASTERN GULF COAST
AND SOUTHEAST ALASKA. CONTRAST OF RIDGE WITH THERMAL TROUGH OVER
INTERIOR ALASKA CONTINUES TO GENERATE GUSTY SOUTHEAST WINDS THROUGH
CHANNELED AREAS OF SOUTHCENTRAL ALASKA. ESPECIALLY TURNAGAIN AND KNIK
ARMS. GRADIENT SLACKENS A LITTLE THIS MORNING BUT RETIGHTENS THIS
AFTERNOON AND EVENING DUE TO DIURNAL STRENGTHENING OF THE INTERIOR
THERMAL TROUGH.
SMALL 1002 MB LOW APPROX 45 NM NORTHEAST OF KODIAK CITY IS POORLY
RECOGNIZED BY THE MODELS BUT IS EXPECTED TO TO REMAIN MAINLY
STATIONARY THROUGH THIS EVENING THEN WEAKEN AND DISSIPATE OVER
EASTERN BRISTOL BAY SUNDAY EVENING. KODIAK ISLAND WILL REMAIN UNDER
EASTERLY FLOW AND PERSISTENT RAINS INTO TUESDAY. EXPECT PERIODS OF
SHOWERS OVER BRISTOL BAY AND THE KUSKOKWIM DELTA. MOSTLY SUNNY FOR
THE KUSKOKWIM VALLEY THIS WEEKEND THANKS TO THE THERMAL TROUGH.
GOOD RUN TO RUN CONSISTENCY IN MODELS HANDLING OF SMALL 1001 MB LOW
NOW APPROX 210 NM WEST OF SAINT PAUL. FEATURE PROGGED TO MOVE TO JUST
NORTH OF DUTCH HARBOR SUN NIGHT AND WEAKEN SLIGHTLY. SHOWERS WILL
PERSIST ACROSS THE EASTERN BERING NEAR ALEUTIANS AND ALASKA
PENINSULA.
OUT WEST WEAK HIGH PRESSURE WILL CONTINUE OVER THE CENTRAL AND
WESTERN BERING. STRATUS AND FOG PRIMARY ISSUE THROUGH 60 HOURS.

.LONG TERM...
DEVELOPMENT OF SOUTHERLY FLOW ALOFT OVER THE GULF OF ALASKA AND
SOUTHERN MAINLAND BEGINNING AT 60 HOURS WILL ACT TO STEER MORE LOW
PRESSURE SYSTEMS INTO THE GULF AND TOWARD SOUTHERN ALASKA. NEXT WEEK
EXPECTED TO BE WARM AND WET.
ALSO LARGE 979 MB NORTH PACIFIC LOW PROGGED TO SKIM JUST SOUTH OF THE
WESTERN ALEUTIANS SUNDAY NIGHT THROUGH TUESDAY. GALE FORCE WINDS
EXPECTED IN ADVANCE OF ITS WELL ORGANIZED FRONT.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

ASB MAY 07