Small Craft Advisory 125, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
400 PM AKST MON FEB 14 2011

.ANALYSIS AND UPPER LEVELS...
ANOTHER COLD AND DRY DAY CONTINUES ACROSS THE MAINLAND WITH AN ARCTIC
AIR MASS FIRMLY SITUATED OVER MUCH OF THE STATE AND AN UPPER LEVEL
RIDGE BUILDING IN FROM THE WEST. WARNING LEVEL GAP WINDS ARE
OCCURRING THROUGH THE COPPER RIVER DELTA AND AND OTHER FAVORABLE
NORTH-SOUTH PASSES ALONG THE NORTH GULF COAST SUCH AS THOMPSON PASS.
BREEZY CONDITIONS ARE ALSO PREVALENT ALONG COOK INLET AND THE
MATANUSKA VALLEY AS DUE TO A PRESSURE GRADIENT BETWEEN A DEPARTING
LOW IN THE SOUTHERN GULF AND HIGHER PRESSURE INLAND. THE UPPER LEVEL
JET ASSOCIATED WITH THE AFOREMENTIONED RIDGE IS CURRENTLY LOCATED
ALONG A LINE FROM BARROW TO KODIAK.

CONDITIONS ARE CALM OVER THE EASTERN BERING SEA AS WELL WITH THE
REGION DOMINATED BY BOTH THE UPPER LEVEL AND SURFACE BASED HIGH
PRESSURE AREAS. WINDS HAVE DIMINISHED OVER THE AKPEN AND EASTERN
ALEUTIANS AS THE UPPER LEVEL JET SHIFTS EASTWARD INTO SOUTHWEST
ALASKA. A FEW STRAY COLD AIR ADVECTION SHOWERS ARE AFFECTING THE
PRIBILOFS AND AKPEN...BUT THESE ARE QUICKLY DISSIPATING AS THE
NORTHERLY FLOW LESSENS. A WEATHER FRONT IS PRESSING EASTWARD OVER THE
WESTERN AND CENTRAL ALEUTIANS ON THE BACKSIDE OF THE UPPER LEVEL
RIDGE.

.MODEL DISCUSSION...
MODELS ARE IN VERY GOOD AGREEMENT SYNOPTICALLY WITH REGARDS TO THE
PROGRESSION AND STRENGTH OF THE UPPER LEVEL RIDGE THROUGH THE END OF
THE WEEK. MODELS ALSO INITIALIZED WELL WITH TWO SUBTLE UPPER LEVEL
SHORT WAVES CURRENTLY OVER SOUTHCENTRAL ALASKA THAT ARE ENHANCING THE
GAP WINDS ALONG THE COAST AND THE MAT VALLEY. THERE ARE SOME
DISCREPANCIES WITH THE TIMING OF A DECAYING WEATHER FRONT THAT MOVES
INTO SOUTHWEST ALASKA ON TUESDAY AFTERNOON...BUT THESE SHOULD HAVE
LITTLE IMPACT ON THE FORECAST.

.SHORT TERM FORECAST...HIGH WIND WARNINGS FROM THE EASTERN HALF OF
PRINCE WILLIAM SOUND THROUGH THE COPPER RIVER DELTA REMAIN IN EFFECT
TROUGH THE NIGHT. STRONG WINDS WILL REMAIN ALONG THE NORTH GULF COAST
INTO THE DAY TUESDAY AND THEN FINALLY TAPER OFF AS THE PRESSURE
GRADIENT SIGNIFICANTLY WEAKENS. WHILE THE NORTH GULF COAST WILL BE
THE WINDIEST PLACE THERE WILL BE CONTINUED STRONG WINDS THROUGH THE
NIGHT AROUND KODIAK ISLAND NORTHWARD THROUGH THE MAT-SU VALLEY. WIND
CHILLS ARE ALSO A CONCERN WITH WIND CHILL ADVISORIES FOR 40 BELOW
ZERO AND COLDER WIND CHILLS ARE IN EFFECT IN PORTIONS OF THE SUSITNA
VALLEY AS WELL AS THE COPPER RIVER BASIN AND THOMPSON PASS. THE
STRONG NORTHERLY WINDS WILL HELP KEEP SKIES CLEAR OVER THE NEXT FEW
DAYS FOR AREAS FROM THE ALASKA RANGE EAST.
SOUTHWEST ALASKA...ANOTHER COLD NIGHT TONIGHT BEFORE CLOUDS MOVE IN
AND TEMPERATURES MODERATE IN THE SOUTHERLY FLOW.
A LARGE STORM SYSTEM WILL IMPACT THE WESTERN ALEUTIANS AND WESTERN
BERING SEA FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT.

.LONG TERM FORECAST...CONSIDERABLE DIVERGENCE IN MODELS SOLUTIONS
THIS WEEKEND MAKES THE LONG TERM FORECAST QUITE UNCERTAIN AT THIS
TIME. PROJECTED UPPER LEVEL PATTERNS ARE QUITE DIFFERENT WHICH
TRANSLATES TO VERY DIFFERENT FORECAST SOLUTIONS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...HIGH WIND WARNING 131 135. WIND CHILL ADVISORY 131 141 145.
MARINE...GALE 121 129 130 132 150 155 165 170 171 172 175 179 180
185.
STORM WARNING 176.
HEAVY FREEZING SPRAY ALL GULF COAST AREAS AND AREAS 150 160 185.
FIRE WEATHER...NONE.

FEB 11