Small Craft Advisory 804, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT FRI OCT 7 2005

.DISCUSSION...

UPPER JET IS RIDING ALONG 50N THIS MORNING WITH JET STREAK OF 170 KT
JUST SOUTH OF THE ALEUTIANS. SATELLITE IMAGERY SHOWS A LARGE UPPER
LOW CENTERED NEAR THE PRIBILOFS WITH A SECONDARY CENTER OVER THE
NORTHWEST BERING SEA. THERE ARE SEVERAL VORT-MAXES EMBEDDED WITHIN
THIS CIRCULATION HELPING TO FOCUS SHOWER ACTIVITY. GUSTY WINDS ARE
NOTED ON THE BACK SIDE OF THIS LOW IN THE COLD ADVECTION REGION WITH
GALES EXTENDING ACROSS THE CENTRAL AND EASTERN ALEUTIANS. MEANWHILE
AN OCCLUDED FRONT IS MOVING ONSHORE OVER SOUTHWEST ALASKA. WITH
TEMPERATURES IN THE 30S ACROSS THE KUSKOKWIM VALLEY AND DELTA SOME
PRECIP WILL FALL IN THE FORM OF SNOW AS THE FRONT MOVES INLAND. A
WEAK LOW IS ALSO LOCATED JUST SOUTH OF MONTAGUE ISLAND WITH A SURFACE
TROUGH EXTENDING SOUTHEASTWARD ACROSS THE GULF. MIDDLETON RADAR SHOWS
A LINE OF RAIN IN THE VICINITY OF THE TROUGH MOVING FROM THE NORTHERN
GULF INTO WESTERN PRINCE WILLIAM SOUND. SOME OF THIS MOISTURE IS
MAKING IT OVER THE KENAI MOUNTAINS IN THE FORM OF SCATTERED SHOWERS.
ELSEWHERE ACROSS SOUTHCENTRAL MAINLY DRY CONDITIONS.

NAM/GFS/UKMET MODELS ALL IN FAIR AGREEMENT THIS MORNING WITH SYNOPTIC
FEATURES. THE GFS/UKMET ARE SLOWER THAN THE NAM IN WEAKENING THE
EASTERN BERING LOW. PREFER THIS SOLUTION AND THE RESULTANT STRONGER
WINDS ACROSS THE EASTERN ALEUTIANS AND AKPENN TODAY. ALSO PREFER THE
GFS SOLUTION WITH EVOLUTION OF SIGNIFICANT LOWS ON SUNDAY.

NOT MUCH WILL CHANGE OVER SOUTHCENTRAL THE NEXT COUPLE DAYS. AS THE
NORTHERN GULF LOW DISSIPATES TODAY THE OCCLUDED FRONT WILL MOVE
INTO THE KODIAK ISLAND WATERS. ALL MODELS INDICATE A TRIPLE POINT
LOW FORMING EAST OF KODIAK ISLAND THIS AFTERNOON AND DRIFTING TO
THE SOUTHERN KENAI PENINSULA SATURDAY AFTERNOON BEFORE DISSIPATING.
THIS WILL KEEP RAIN FOCUSED ALONG COASTAL REGIONS...NAMELY PRINCE
WILLIAM SOUND AND COOK INLET WITH SOME RAIN OVER THE WESTERN KENAI
ON SATURDAY. INLAND AREAS WILL REMAIN DRY. MODELS DEVELOP A LOW THAT
IS CURRENTLY NEAR 40N/170E AND TRACK IT TO THE EASTERN GULF SUNDAY
AND NEAR YAKUTAT SUNDAY NIGHT WITH THE COMMON SECONDARY LOW FORMING
OVER PRINCE WILLIAM SOUND. THE MODELS HAVE INDICATED THIS THE PAST
COUPLE RUNS SO AM GAINING A LITTLE CONFIDENCE IN THIS SOLUTION. WITH
GOOD UPPER SUPPORT LOW SHOULD DEEPEN INTO AT LEAST THE LOW 970S.
BASED ON CURRENT TRACK MAIN IMPACT FOR SOUTHCENTRAL WILL BE GALES
OVER THE GULF WATERS AND SOME PRECIP ALONG THE COAST.

THE LOW OVER THE EASTERN BERING WILL SLOWLY WEAKEN THE NEXT COUPLE
OF DAYS. OCCLUDED FRONT WILL STRETCH OUT AND DISSIPATE LATER TODAY
OVER SOUTHWEST ALASKA. THEREFORE...MOST OF PRECIP WILL REMAIN NEAR
THE COAST. SHOWERS AND GUSTY WINDS WILL CONTINUE OVER THE BERING SEA
AND ALEUTIANS THROUGH SATURDAY AND TRANSLATE EASTWARD SUNDAY AS A
SHORT-WAVE RIDGE MOVES ACROSS THE WESTERN AND CENTRAL BERING. THE
NEXT SIGNIFICANT LOW RIDING THE JET OUT OF ASIA IS PROGGED TO
APPROACH THE WESTERN ALEUTIANS SATURDAY NIGHT AND SUNDAY AND TRACK
RIGHT ACROSS THE ALEUTIANS MONDAY. WITH GOOD MODEL AGREEMENT SEE NO
REASON TO STRAY FROM THIS SOLUTION.

LOOKING TO THE EXTENDED FORECAST PERIOD NEAR ZONAL JET CONTINUES
THROUGH MID WEEK WITH SOME SIGNIFICANT AMPLIFICATION NOTED BY THE
END OF NEXT WEEK. THIS WOULD BE A SIGNIFICANT CHANGE FROM THE PAST
MONTH IN WHICH ZONAL FLOW HAS DOMINATED. IF THIS VERIFIES EXPECT
COLDER TEMPS ACROSS MUCH OF ALASKA BY THE END OF NEXT WEEK AND
POSSIBLY THE FIRST SNOWFALL FOR SOME LOCATIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 155 165 170 171 172.
FIRE WEATHER...NONE.

SEB OCT 05