Small Craft Advisory 108, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
430 AM AST SUN JAN 28 2007

.DISCUSSION...

UPPER LEVELS...BLOCKING RIDGE IS CENTERED JUST OFF THE BRITISH
COLUMBIA COAST WITH A HIGH AMPLITUDE TROUGH TO THE WEST FROM THE
BERING SEA ALL THE WAY DOWN TO 20N LATITUDE. THE UPPER JET EXTENDS
EASTWARD OUT OF ASIA BETWEEN 30N AND 40N ALL THE WAY TO ABOUT 160W.
IT THEN MAKE A LEFT TURN AND HEADS DUE NORTH UP TO SOUTHCENTRAL
ALASKA. ONLY CHANGE TO THIS PATTERN EXPECTED OVER THE NEXT SEVEN
DAYS IS FOR RIDGE TO BUILD NORTH AND WESTWARD UP INTO MAINLAND
ALASKA. THIS WILL CURVE THE JET BACK TOWARD THE BERING SEA AND
FORCE THE STORM TRACK FARTHER WEST. SO FOR THE SHORT-TERM THE
PARADE OF STORMS ALONG WITH IMPRESSIVE MOISTURE TRANSPORT AND
WARM AIR ADVECTION WILL CONTINUE TO TRACK FROM THE EAST PACIFIC
NORTHWESTWARD INTO THE BERING SEA.

MODELS..MODELS ARE IN GOOD AGREEMENT THROUGH 84 HRS. THEY INDICATE A
SERIES OF LOWS DEVELOPING SOUTH OF THE ALEUTIANS THROUGH NEXT WEEK
THAT WILL CONTINUE TO FOLLOW THE PINEAPPLE EXPRESS NORTHWARD INTO THE
BERING. EACH LOW WILL SUCCESSIVELY WEAKEN IN THE CENTRAL BERING AS
THE NEW ONE MOVES NORTH.

IN THE WEST..WEST SIDE OF THE LOWS WILL CONTINUE TO SEE BLUSTERY
NORTHERLY WINDS THAT WILL REDUCE VISIBILITY IN BLOWING SNOW.
SIGNIFICANT WAA ON THE EAST SIDE OF THE SYSTEMS WILL CONTINUE TO KEEP
THE AK PENN AND BRISTOL BAY MOSTLY IN THE CLEAR WITH STRONG SOUTHERLY
WINDS BUT MAINLY RAIN RATHER THAN SNOW.

IN THE EAST..DOWNSLOPING WILL CONTINUE ACROSS THE ANCHORAGE BOWL AND
MATANUSKA VALLEY. UPSLOPE FLOW ASSOCIATED WITH THE UPPER LEVEL
SOUTHERLY FLOW ACROSS THE SUSITNA VALLEY WILL RESULT IN SOME HEAVIER
SNOW AMOUNTS. HOWEVER WILL NEED TO WATCH TEMPS CLOSELY AS CHANNELED
NORTHEAST WINDS ARE DRIVING THE TEMPS UP ACROSS THE MAT-SU VALLEYS.
FROPA THIS MORNING ACROSS SOUTHCENTRAL WILL PRODUCE STRONG WINDS
ACROSS THE NORTH GULF COAST FROM CORDOVA TO TURNAGAIN ARM. PRECIP
WILL BE HEAVY AT TIMES AROUND PRINCE WILLIAM SOUND. AGAIN..WAA WILL
KEEP MOST OF THIS IN THE FORM OF RAIN BUT WILL NEED TO WATCH THOMPSON
PASS UNTIL TEMPS WARM ENOUGH TO CHANGE PRECIP OVER. NEXT EVENT TO
WATCH IS THE TIGHTENING GRADIENT BETWEEN THE NEXT LOW PRESSURE SYSTEM
IN THE WEST AND THE EASTERN BLOCKING RIDGE. MAY NEED TO ISSUE A HIGH
WIND WARNING FOR TURNAGAIN ARM BY MON EVENING.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FLOOD WARNING 121.
MARINE...STORM WARNING 130.
         GALE WARNING 120 125 132 138 150 155 160 165 170 172 176
                      185.
         HVY FZG SPRY 185.
FIRE WEATHER...NONE.

RNW JAN 07