Small Craft Advisory 810, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTH CENTRAL AND SOUTHWEST ALASKA
200 PM AKDT SUN OCT 19 2008

.MODEL DISCUSSION...THE MODELS INITIALIZED WELL THIS MORNING. THE
FORECAST TRENDS LOOK REASONABLE AND CONVERGE ON A COMMON SOLUTION
WITH TWO MAJOR STORM CENTERS FORECAST TO IMPACT THE GULF OF ALASKA
AND ALEUTIANS TUE AND WED.

.UPPER LEVELS...
PROGRESSIVE PATTERN CONTINUES. LOW AND ASSOCIATED TROUGH OVER THE
GULF/NE PACIFIC MOVE INTO WESTERN CANADA AS A LONG WAVE TROUGH DIGS
OVER THE EASTERN BERING SEA/N PACIFIC MON NIGHT. BY TUE AFTERNOON
THIS TROUGH EXTENDS FROM WESTERN ALASKA TO THE N PACIFIC ALONG 160W.
A SECONDARY CENTER MOVES TO NEAR THE CHUKCHI SEA WED AS THE BASE OF
THROUGH ROTATES TO THE EASTERN GULF. YET ANOTHER TROUGH MOVES OFF THE
RUSSIAN MAINLAND TO THE BERING SEA AND NORTH PACIFIC ALONG 170E WED.

.SHORT TERM FORECAST...
EAST...A 978 MB VERTICALLY STACKED LOW CENTER SE OF KODIAK HAS
TEMPORARILY STALLED. THIS CENTER IS EXPECTED TO WEAKEN THROUGH
TONIGHT AS IT TRACKS TO THE EASTERN GULF OF ALASKA. THE ASSOCIATED
FRONT MOVED INLAND OVER SOUTH CENTRAL/NORTH GULF OVERNIGHT.
SATELLITE PICTURES SHOW WIDESPREAD SHOWERS OVER MUCH OF THE GULF AND
COASTAL AREAS. EXPECT SHOWERY CONDITIONS WILL CONTINUE MAINLY OVER
THE GULF WITH GENERALLY CLOUDS WITH A CHANCE OF SHOWERS INLAND
THROUGH TUE. MODELS HAVE CONVERGED ON A COMMON SOLUTION WITH NEXT
MAJOR SYSTEM TO IMPACT THE GULF OF ALASKA. CURRENT TRACK WILL TAKE A
960S MB CENTER TO THE SOUTHERN GULF OF ALASKA TUE NIGHT. THIS CENTER
THEN MOVES SE OF YAKUTAT AND WEAKENS INTO THE 970S WED. THE MAIN
IMPACT WITH BE GALE TO STORM FORCE WINDS WITH COLD AIR ADVECTION ON
THE BACKSIDE OF THIS SYSTEM. EXPECT FAIRLY BRISK GAP FLOWS OVER MUCH
OF THE NORTH GULF/SOUTH CENTRAL TUE NIGHT/WED.

.WEST...WINDS OVER THE SW MAINLAND/EASTERN BERING SEA/AK PEN WILL
DIMINISH THROUGH TONIGHT AS LOW CENTER SE OF KODIAK MOVES EAST. THE
SATELLITE PICTURE SHOWS A LOW CENTER SW OF THE GULF OF ANADYR AND A
WEAK FRONTAL BOUNDARY EXTENDING SOUTH OF AN OPEN WAVE NEAR 55N 177W.
THE NORTHERN MOST LOW WILL WEAKEN AS IT MOVES TO JUST SOUTH OF THE
WESTERN AK PEN TUE MORNING. EXPECT BRISK WINDS WITH COLD ADVECTION ON
THE BACKSIDE OF THIS CENTER. THE SOUTHERN MOST LOW WEAKENS AS IT
MOVES INTO BRISTOL BAY MON EVENING...WITH THE ASSOCIATED FRONTAL
SYSTEM EXTENDING ALONG SW AK AND ACROSS THE AK PEN. WE DO NOT EXPECT
MUCH WIND OR PRECIPITATION OUT OF THIS SYSTEM.
THE MODELS ARE CONVERGING ON A SOLUTION FOR THE NEXT STORM CENTER TO
HIT THE ALEUTIANS. THE CENTER IS EXPECTED TO MOVE ACROSS THE DATE
LINE NEAR 50N TUE NIGHT WITH A PRESSURE IN THE 950S (COMPROMISE OF
ECMWF/GFS PRESSURES). THE CENTER SHOULD SLOWLY WEAKEN AS IT TRACKS
SOUTH OF THE AK PEN THU MORNING. EXPECT STORM FORCE WINDS WITH THIS
ONE. TEMPERATURES SHOULD WARM RATHER QUICKLY WITH APPROACH OF THIS
SYSTEM...SO ANY BLOWING SNOW SHOULD BE SHORT LIVED AS PRECIPITATION
BECOMES MIXED OR CHANGES TO RAIN AS SYSTEM PROGRESSES ACROSS THE
CHAIN.

.LONG TERM FORECAST...IT LOOKS LIKE WEAK SOUTHERLY FLOW WILL DEVELOP
ACROSS THE STATE AND BRING SOMEWHAT MILDER WEATHER. BY NEXT WEEKEND
THINGS DRY OUT WITH SOUTHERN ALASKA IN BETWEEN MAJOR WEATHER SYSTEMS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 352 411 413
      NONE ALONG COASTAL AREA AT THIS TIME. GALE GUSTS IN THE WESTERN
        GULF AND ZONES 150 TONIGHT.
FIRE WEATHER...NONE.

RMC OCT 08