Small Craft Advisory 15, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
530 AM AST THU JAN 5 2006

DISCUSSION...
GFS AND ETA IN RELATIVELY GOOD AGREEMENT FOR THIS MORNINGS FORECAST
PACKAGE. SOLUTION DIFFERENCES ARE EVIDENT WITH THE LOCATION AND DEPTH
OF A RAPIDLY DEVELOPING LOW SOUTH OF THE EASTERN ALEUTIANS AT 60
HOURS. THE ETA HANDLING THIS LOW MUCH MORE AGGRESSIVELY MAY BE
ATTRIBUTED TO THE DOMAIN RESTRICTIONS. ON THE OTHER HAND THE GFS
UNREALISTICALLY DEPICTS THE LOW CONTINUING TO DEEPEN TO 968 MB WHILE
IT IS VERTICALLY STACKED. THE CONSENSUS WAS TO BLEND THE TWO MODELS
AND MEET SOMEWHERE IN THE MIDDLE. THE SHORT TERM DIFFERENCES BETWEEN
THE MODELS WERE NEGLIGIBLE. SO CONFIDENCE IN THE SHORT TERM IS FAIRLY
HIGH AND MEDIUM TO LONG RANGE IS LOW.

UPPER AIR...EVERYTHING IS REVOLVING AROUND A MASSIVE UPPER LOW IN THE
WESTERN BERING SEA JUST EAST OF THE KAMCHATKA PENINSULA. THIS FEATURE
WILL CONTORT AS IT GOES THROUGH CYCLES OF REDEVELOPING THROUGH THE
WEEKEND. IT WILL HOWEVER REMAIN RELATIVELY STATIONARY OVER THE
WESTERN BERING SEA AND EASTERN SIBERIA. SOUTH OF THE UPPER
LOW...SHORT WAVES ARE TRAVELING WEST TO EAST ALONG THE 100 TO 135 KT
JET STRETCHING FROM SOUTHERN JAPAN TO THE PACIFIC NORTHWEST OF THE
CONUS. MODELS ARE NOT INDICATING ANY SIGNIFICANT CHANGES IN THIS
PATTERN.

SURFACE...980 MB LOW IN THE GULF IS DISSIPATING AS IT DRIFTS
NORTHEASTWARD TOWARD THE AKPEN. THE REMNANTS WILL BE ABSORBED BY THE
NEXT LOW APPROACHING THE SAME AREA FRIDAY NIGHT. THE ASSOCIATED
OCCLUSION WILL INVADE SOUTHCENTRAL LATE THURSDAY NIGHT INTO FRIDAY
MORNING PUTTING AN END TO SOME VERY PLEASANT WEATHER. WITH SOME VERY
COLD TEMPERATURES IN PLACE...EXPECTING TO START OUT AS SNOW ALONG THE
IMMEDIATE COAST AND CHANGE OVER OR MIX WITH RAIN DURING THE DAY
FRIDAY. ALSO EXPECTING VERY STRONG WINDS THROUGH THE COPPER RIVER
DELTA DUE TO THE EXTREME TEMPERATURE AND PRESSURE GRADIENT ACROSS THE
CHUGACH MOUNTAIN RANGE. ANCHORAGE AND WESTERN KENAI WILL MISS OUT ON
ANY PRECIP DUE TO DOWNSLOPING WINDS ALOFT.

FURTHER WEST...SOUTHWEST AND INTERIOR WILL REMAIN DRY WHILE ALL THE
DYNAMICS REMAIN WELL SOUTH OF THE REGION. THE EXCEPTION WILL BE
PATCHES OF LIGHT SNOW OR FLURRIES INDUCED BY OROGRAPHICS OR OTHER
LOCAL EFFECTS. HIGH WIND WARNING PANNED OUT YESTERDAY WITH 70 MPH
WINDS REPORTED IN SHEMYA. THE SYSTEM RAPIDLY WEAKENED AS IT MOVED
INTO THE CENTRAL ALEUTIANS WHEN A TRIPLE POINT LOW FORMED SOUTH OF
ADAK. WEAK COLD AIR ADVECTION OVER MUCH OF THE EASTERN AND CENTRAL
BERING SEA IS CAUSING OCCASIONAL SNOW AND CLOUDY CONDITIONS OVER THIS
REGION. PRECIP AND WINDS WILL INTENSIFY AS SYSTEMS SPIN UP SOUTH OF
THE ALEUTIANS AND MOVE EASTWARD INTO THE NORTH GULF.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALES 138.

AB JAN 06