Small Craft Advisory 831, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT SAT OCT 15 2005

.DISCUSSION...
ANALYSIS - THE COLD ANCHOR UPPER LOW IS OVER SIBERIA THIS MORNING
WITH AN UPPER RIDGE ALONG 170W OR SO. THE BIG STORY IS A HIGH
AMPLITUDE UPPER LOW/TROUGH COMPLEX THAT IS POSITIVELY TILTED FROM
NEAR THE POLE THROUGH THE CENTRAL INTERIOR TO AN UPPER LOW CENTER S
OF SAND POINT. THE UPPER TROUGH THAT EXTENDS FROM THE SOUTHERN UPPER
LOW GOES WAY INTO THE TROPICS. THIS SYSTEM SUPPORTS A 975 MB STORM
CENTER ABOUT 200 NM SE OF SAND POINT AT 12Z. A TRIPLE POINT HAS
DEVELOPED 18Z AROUND 55N 145W AS PER SATELLITE AND THE SUPPORTED COLD
FRONT EXTENDS SW ALSO INTO THE TROPICS. SATELLITE IMAGERY INDICATES A
WAVE ON THIS FRONT AROUND 40N 165W. THE JET AT 250 MB 12Z HAS
BUCKLED. THERE IS A 150 KT JET OVER THE FRONT INTO THE PANHANDLE. A
NORTHERLY 100 KT BRANCH IS ALONG 175W. OUT WEST ANOTHER 125KT BRANCH
FROM CENTRAL ASIA EXITS JUST W OF SHEMYA. SATELLITE IMAGERY REVEALS A
MODERATE FRONT ALONG 178W OR SO WITH A WAVE NEAR SHEMYA ASSOCIATED
WITH THE 970 MB SURFACE LOW IN SIBERIA.

AER FORECASTS - KODIAK IS GETTING ONSHORE FLOW FROM THE STORM AT THE
MOMENT WITH AREAS OF GALES IN OUR VAST MARINE AREAS. IT IS VERY
UNUSUAL TO GET STRONG ONSHORE FLOW AT KODIAK WITHOUT RAIN SO FAR. AS
THE STORM CENTER TRACKS TOWARD SITKA ALMOST ALL OF THE PRECIP WILL
MISS THE EASTERN GFE DOMAIN. AS THE UPPER RIDGE BUILDS INTO THE
WESTERN INTERIOR TONIGHT THERE WILL BE SIGNIFICANT CLEARING WITH
PATCHY FOG OR FROST AND SOME OFFSHORE FLOW. THE NEXT BEAST IS A
RAPIDLY MOVING SYSTEM SPAWNED FROM THE MAJOR UPPER LOW. THE UPPER
RIDGE BEGINS TO FLATTEN BY SUNDAY NIGHT AND A FRONT WILL GET TO
SOUTHCENTRAL ON MONDAY WITH LOTS OF RAIN AND WIND. THE MODELS
FORECAST A PATTERN THAT PROMISE STRONG WINDS INCLUDING TURNAGAIN ARM.

ALU FORECASTS - AS THE STORM CENTER MOVES INTO THE GULF A WEAK
SURFACE RIDGE WILL MOVE INTO THE EASTERN BERING SEA THIS EVENING.
THIS WILL NOT PREVENT A COLD FRONT FROM MOVING ONTO OUR WESTERN COAST
AROUND 12Z SUN. WARM ADVECTION AHEAD OF THIS FRONT INDICATES THAT ANY
SNOW THERE WILL RAPIDLY CHANGE TO RAIN. THE JET OFF ASIA GETS CRANKED
UP ON SUNDAY WHICH HELPS TO DEVELOP A 987 MB STORM FORCE LOW 200
MILES NORTH OF SHEMYA AT 18Z...THEN MOVES THE LOW TO NUNIVAK ISLAND
AROUND 970 MB EARLY MONDAY MORNING. EXPECT LOTS OF WIND WITH THESE
SYSTEMS PLUS WARM AIR AHEAD OF EACH ONE. THE MODELS ARE IN GOOD
AGREEMENT ON THESE.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM 175 176. GALES 132 138 150 155 170 171 172 179.
FIRE WEATHER...NONE.

JC OCT 05