Small Craft Advisory 918, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT THU OCT 5 2006

.DISCUSSION...

SYNOPSIS...A WEAKENING UPPER LEVEL LOW OVER THE NORTHERN INTERIOR IS
PULLING NORTH AND FUSING WITH AN UPPER LOW DROPPING SOUTH FROM THE
ARCTIC SEA THROUGH THE BERING STRAIT.  AT THE SURFACE A POTENT TROUGH
IS MOVING NORTH OUT OF THE GULF OVER THE COPPER RIVER BASIN WHILE
ANOTHER LOW SOUTH OF THE ALEUTIANS HEADS WEST OVER TOP THE LARGE HIGH
IN THE NORTH PACIFIC.

MODEL ANALYSIS...GENERAL AGREEMENT AMONG THE NUMERICAL SOLUTIONS
THROUGH 48 HOURS.  THE 0Z AND 12Z GFS RUNS HAVE CONTINUED TO SLOW THE
EASTERN PROGRESSION OF THE CURRENT 998MB LOW SOUTH OF THE CENTRAL
ALEUTIANS AND WILL USE THIS FOR THE AFTERNOON PACKAGE. AFTER 48 HOURS
THERE IS VERY POOR AGREEMENT AMONG THE MODELS AND HAVE GENERALLY GONE
WITH THE PREVIOUS FORECAST DURING THE MID TERM.  AT 72 HOURS THE
MODELS COME IN LINE AGAIN SIGNIFICANTLY DEEPENING A LOW NEAR 40N 165W
AND RUNNING IT DUE NORTH TO BRISTOL BAY EARLY NEXT WEEK.

SHORT TERM...HAVE DECREASED THE WINDS OVER THE WESTERN ALEUTIANS AS
THE FRONT IS NOT AS STRONG AS PREVIOUS ADVERTISED...BUT ARE KEEPING
GALES IN THE CENTRAL AND EASTERN ALEUTIAN ZONES. MID AND LOW LEVEL
MOISTURE WILL KEEP CLOUDS AROUND SOUTH CENTRAL ALASKA WITH SHOWERS
THROUGH THE WEEKEND.  AS SOUTHWEST FLOW IS MAINTAINED WITH THE UPPER
LOW STATIONED OVER THE SEWARD PENINSULA...LOOKS LIKE WET WINDY AND
SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE THE RULE. RAIN ASSOCIATED
WITH NEXT LOW WILL MOVE INTO COOK INLET FRIDAY MORNING.

LONG TERM...HAVE STARTED TO BUY INTO THE PROGNOSIS OF A VERY DEEP LOW
IMPACTING THE CENTRAL AND EASTERN ALEUTIANS SUNDAY NIGHT INTO MONDAY
WITH THE POSSIBILITY OF GALES AND HIGH WIND WARNINGS FOR THESE AREAS.

AS THIS LOW DEEPENS IT ACTS TO AMPLIFY A LARGE RIDGE CENTERED OVER
SOUTHEAST ALASKA SETTING IN MOTION THE CHANGE FROM A LARGELY ZONAL
STABLE HEMISPHERIC PATTERN TO A HIGHLY AMPLIFIED 4 WAVE PATTERN BY
MIDWEEK NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 170 172
FIRE WEATHER...NONE

SDM OCT 06