Small Craft Advisory 635, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
214 PM AKDT SAT AUG 23 2014

.ANALYSIS AND UPPER LEVELS...

UPPER LEVEL TROUGH EXTENDS FROM EASTERN RUSSIA TO WESTERN AK THIS
AFTERNOON WITH EMBEDDED CUT-OFF LOWS OVER KAMCHATKA AND THE
CENTRAL ALEUTIANS. A RIDGE IS OVER SOUTHCENTRAL AK WHILE A WEAK
TROUGH IS OVER THE NORTHEAST PANHANDLE. AT THE SURFACE...A BROAD
AREA OF LOW PRESSURE OVER THE BERING HAS A CENTER NORTH OF
ATKA...WITH A WEAKENING LOW RAPIDLY LOSING DEFINITION NEAR THE
END OF THE AKPEN. A RIDGE IS OVER THE GULF OF AK AND MAINLAND AK.
A WEATHER FRONT IS OVER KODIAK ISLAND AND THE WESTERN GULF OF
AK...AND A SECOND FRONT IS ACROSS THE EASTERN ALEUTIANS.

&&

.MODEL DISCUSSION...

MODELS IN AGREEMENT WITH THE PROGRESSIVE PATTERN TAKING SHAPE OVER
THE REGION. THE UPPER RIDGE OVER THE GULF WILL BREAK DOWN AND
ALLOW THE ALEUTIAN LOW TO MOVE TO THE NORTHEAST GULF COAST BY TUE
AFTERNOON. THIS WILL ALSO ALLOW THE INITIAL SURFACE FRONT TO
REACH THE NORTHEAST GULF TONIGHT...AND THEN THE MAIN FRONT WILL
MOVE ACROSS THE GULF ON MON. THE EASTWARD PROGRESSION OF THESE
FEATURES WILL THEN ALLOW A LOW TO MOVE ACROSS EASTERN RUSSIA INTO
THE NORTHERN BERING SUN NIGHT THROUGH TUE AFTERNOON.

&&

.SHORT TERM FORECAST...

SOUTHCENTRAL ALASKA...

THE INITIAL FRONT WILL BRING RAIN TO THE GULF COAST
TONIGHT...ALTHOUGH SOME DOWNSLOPING WILL INITIALLY KEEP CONDITIONS
DRY DOWNWIND OF THE CHUGACH AND KENAI MOUNTAINS. ON SUN THE
DOWNSLOPING ENDS AND THE PRECIPITATION BECOMES MORE WIDESPREAD.
ON MON RAIN WILL BE ENHANCED BY THE SECOND FRONT AS WELL AS THE
UPPER LOW MOVING ACROSS THE REGION. RAIN WILL TAPER OFF TO SHOWERS
ON TUE.

SOUTHWEST ALASKA...

RAIN WILL OVERSPREAD THE AREA TONIGHT AND REMAIN UNTIL THE UPPER
LOW HAS MOVED EAST ON TUE. SOME WIND THROUGH CHANNELED TERRAIN IS
EXPECTED TONIGHT.

BERING SEA/ALEUTIANS...

SHOWERS CAN BE EXPECTED THROUGH TUE BENEATH THE UPPER LOW...AND
WILL BE REENHANCED AS THE NEXT LOW SLIDE SOUTH FROM THE NORTHERN
BERING ON TUE.

&&

.LONG TERM FORECAST...

AN UPPER LEVEL WEAK RIDGE WILL BRIEFLY BRING DRIER CONDITIONS FOR
WEDNESDAY FOR SOUTHEAST MAINLAND. BY THURSDAY SEVERAL UPPER LEVEL
WEAK SHORTWAVES WILL TRACK THROUGH THE REGION KICKING OFF
SCATTERED SHOWERS. AN UPPER LEVEL TROUGH DROPS DOWN FROM THE NORTH
AND COMBINING WITH A LOW PRESSURE SYSTEM ENTERING THE BRISTOL BAY
AREA WILL BRING MORE CLOUDS AND SHOWERS TO THE REGION GOING INTO
NEXT WEEKEND. THE BERING SEA WILL HAVE A LOW PRESSURE SYSTEM
APPROACHING THE WESTERN ALEUTIANS BY WEDNESDAY. THE FRONTAL
BOUNDARY ASSOCIATED WITH THIS LOW WILL BE POSITIONED THROUGH THE
WESTERN ALEUTIANS. THIS LOW WILL TRACK THROUGH THE BERING SEA AND
REACH THE SOUTHWEST ALASKA COASTLINE BY FRIDAY NIGHT. THIS SYSTEM
WILL BRING WIDESPREAD RAIN WITH STRATUS AND FOG GOING INTO NEXT
WEEKEND. &&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...131 138.
FIRE WEATHER...NONE.

&&

DS/PLD AUG 14