Small Craft Advisory 388, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 PM ADT FRI APR 27 2007

.MODEL DISCUSSION...MODELS ALL HAVE THE SAME GENERAL IDEA AS TO WHAT
SHOULD HAPPEN BUT THERE ARE SOME DIFFERENCE IN THE DETAILS IN REGARDS
TO THE LOW MOVING INTO THE ALEUTIAN ISLANDS. THIS LOW IS CURRENTLY
WEST OF ATTU AND MOVING EASTWARD. THE WEATHER FRONT ASSOCIATED WITH
THIS LOW IS IN THE WESTERN BERING SEA AND A TRIPLE POINT LOW WILL
DEVELOP ALONG THE FRONT NORTHWEST OF ADAK TOMORROW. THE MODELS ALL
DIFFER ON THE EXACT LOCATION AND TIMING OF THIS TRIPLE POINT LOW
DEVELOPING BUT THEY ALL HAVE IT. GOING CLOSER TO THE GFS SOLUTION
WITH THIS SYSTEM.
THE MODELS SEEM TO HAVE A LOCK ON THE GULF OF ALASKA LOW AND EITHER
THE GFS OR NAM CAN BE USED WITH CONFIDENCE.

.ANALYSIS AND UPPER LEVELS...BROAD UPPER LEVEL LONG WAVE TROUGH
REMAINS OVER MAINLAND ALASKA. A SHORT WAVE OVER THE KUSKOKWIM DELTA
IS BRINGING SOME SNOW INTO THAT AREA. THIS WAVE SHOULD WEAKEN AND
DRIFT NORTHWARD OVERNIGHT. THE LOW IN THE GULF CONTINUES TO REMAIN
NEARLY STATIONARY AND SLOWLY WEAKEN. THIS LOW WILL EVENTUALLY
DISSIPATE SOUTHWEST OF YAKUTAT EARLY SUNDAY.
THERE IS A LOW WEST OF ATTU THAT IS PUSHING A WEATHER FRONT INTO THE
WESTERN ALEUTIAN ISLANDS. A TRIPLE POINT ALONG THIS FRONT WILL
PRODUCE A SECONDARY LOW NORTHWEST OF ADAK. BOTH LOWS WILL MOVE
EASTWARD OVER THE WEEKEND WITH THE TRIPLE POINT LOW BECOMING THE MAIN
ONE BY SUNDAY.

.SHORT TERM FORECAST...WIDE RANGE OF WEATHER OVER THE AREA TODAY.
SNOW SHOWERS HAVE FALLEN OVER MOUNTAINOUS AREAS OF THE COPPER RIVER
BASIN INCLUDING THE GLENN HIGHWAY. SNOW HAS ALSO FALLEN AT BETHEL AND
WHILE THERE HAS NOT BEEN PRECIPITATION OVER THE PRIBILOF ISLANDS THEY
REMAIN COLD ENOUGH FOR SNOW IN THE UPPER 20S. RAIN SHOWERS PERSIST
ALONG THE GULF COAST AND INTO THE SUSITNA VALLEY. THE KUSKOKWIM
VALLEY IS THE SUNNY SPOT AROUND THE FORECAST AREA BUT WE ARE STILL
KEEPING AN EYE ON ANY CONVECTIVE BUILD UP LATE THIS AFTERNOON INTO
THIS EVENING. MCGRATH HAD A THUNDERSTORM NEARBY YESTERDAY THOUGH IT
LOOKS LESS LIKELY THAT THEY WILL SEE THUNDER TODAY. A THERMAL LOW IN
THE SOUTHERN SUSITNA VALLEY ALONG WITH AN EAST WEST ORIENTED RIDGE
ALONG THE NORTH GULF COAST IS CAUSING TURNAGAIN ARM AND PARTS OF
ANCHORAGE TO EXPERIENCE WINDS 25 TO 40 MPH THIS AFTERNOON. THESE
WINDS SHOULD DIMINISH LATE IN THE EVENING AS THE RIDGE WEAKENS AND
THE THERMAL LOW DISSIPATES.

.LONG TERM FORECAST...BROAD LONG WAVE UPPER LEVEL TROUGH REMAINS OVER
MAINLAND THROUGH THE MIDDLE OF NEXT WEEK. BY MID WEEK NEXT WEEK A
RIDGE IN THE BERING SEA MAY TRY TO MOVE EASTWARD OVER THE MAINLAND
BUT IT IS STILL TOO FAR OUT TOO KNOW IF THIS RIDGE WILL HAVE ENOUGH
STRENGTH TO MAKE A LARGE IMPACT ON THE WEATHER IN SOUTHERN ALASKA. AT
THIS TIME IT LOOKS TO BE A SHORT LIVED FEATURE...BUT ONE THAT BEARS
WATCHING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 172 175 176.
FIRE WEATHER...NONE.

APR 07