Small Craft Advisory 899, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKST FRI NOV 6 2009

.ANALYSIS AND UPPER LEVELS...

UPPER LEVEL TROUGH OVER ALASKA PERSISTS THIS MORNING WITH A CENTER
OVER THE GULF. UPPER RIDGES ARE OVER THE CANADIAN ROCKIES AND THE
KAMCHATKA PENINSULA...WITH A WEAKER RIDGE OVER THE CENTRAL BERING. AT
THE SURFACE...A LOW PRESSURE CENTER OVER THE GULF IS SLOWLY WEAKENING
WHILE A RIDGE IS ENTERING THE WESTERN BERING.

.MODEL DISCUSSION...

MODELS ARE IN EXCELLENT AGREEMENT FOR THE FIRST FEW DAYS. THE LOW IN
THE GULF SLOWLY WEAKENS AS IT ROTATES ALONG THE NORTHEASTERN COAST. A
SECOND LOW THEN FORMS NEAR THE QUEEN CHARLOTTES SUN AND BECOMES AN
ELONGATED LOW ALONG THE NORTHEAST GULF COAST UNTIL DISSIPATION OCCURS
TUE. IN THE WEST...THE RIDGE REACHES THE WEST COAST OF AK SUN AND IS
FOLLOWED BY A WEATHER FRONT FROM AN EASTERN RUSSIA LOW. THE NEXT LOW
FROM KAMCHATKA BRINGS A SECOND FRONT ACROSS THE ALEUTIANS TO THE WEST
COAST MON. THE FORECAST UTILIZES THE NAM AND GFS IN THE SHORT TERM
AND THEN TRANSITIONS TO THE MORE STABLE EC IN THE MID AND LONG RANGE.

.SHORT TERM FORECAST...

IN THE WEST...AFTER A MORNING HIGH WIND WARNING FOR THE AKPEN...WINDS
WILL RAPIDLY DIMINISH TODAY OVER THE BERING IN RESPONSE TO A
WEAKENING GULF LOW AND A RIDGE MOVING ACROSS THE AREA. A WEAK FRONT
ASSOCIATED WITH THE EASTERN RUSSIA LOW WILL BRING SOME SHOWERS ACROSS
THE BERING AND ALEUTIANS SAT AND SUN. FAIRLY DRY CONDITIONS ARE THEN
EXPECTED THROUGH TUE EXCEPT FOR A FEW SHOWERS AS THE SECOND LOW AND
FRONT MOVE TO THE COAST.

FOR SOUTHWEST AK...STEADY IMPROVEMENT IS EXPECTED AS THE NORTHWESTERN
FLANK OF THE CLOUD SHIELD ASSOCIATED WITH THE GULF LOW WITHDRAWS FROM
THE AREA. DRY CONDITIONS SHOULD PERSIST UNTIL THE FIRST FRONT BRINGS
SHOWERS TO THE COAST SUN AFTERNOON AND THE SECOND FRONT ARRIVES WITH
LESSER AMOUNTS MON AFTERNOON.

SOUTH AND EAST OF THE AK RANGE...LIGHT PRECIPITATION WILL BE LIMITED
TO THE GULF COAST TODAY AND TONIGHT. AS THE LOW MOVES A BIT TO THE
NORTH TONIGHT INCREASED PRECIPITATION IS EXPECTED OVER THE COAST AND
INLAND TO THE WRANGELL MOUNTAINS. SOME OF THIS WILL MOVE TO SOUTH
CENTRAL AS SNOW SUN NIGHT AND MON AS THE WEAKENING REMNANTS OF THE
LOW MOVE TO PRINCE WILLIAM SOUND. LIGHT PRECIP WILL CONTINUE ACROSS
THE AREA UNTIL THE LOW DISSIPATES TUE AFTERNOON.

.LONG TERM FORECAST...

IN THE WEST...SNOW SHOWERS ON NORTHWEST FLOW WILL REDEVELOP AS A
THIRD LOW MOVES ACROSS THE BERING TO BRISTOL BAY AROUND MID-WEEK.
MEANWHILE A NORTH PACIFIC LOW WILL MOVE ALONG THE SOUTHERN SIDE OF
THE ALEUTIAN CHAIN AND BRING SNOW SHOWERS TO SOUTHWEST AK THROUGH THE
MIDDLE OF NEXT WEEK. SOUTHEAST OF THE AK RANGE WILL BE DRY UNTIL THE
SAME LOW MOVES TO PRINCE WILLIAM SOUND THU AND BRINGS THE POTENTIAL
OF SNOW TO THE REGION.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 181
MARINE...GALES 120 130 132 150 155 165 170 171 179 180
FIRE WEATHER...NONE

DS NOV 09