Small Craft Advisory 696, NWS Anchorage, AK

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
613 PM AKDT FRI SEP 12 2014

.ANALYSIS AND UPPER LEVELS...
THE UPPER LEVEL PATTERN IS PRETTY BASIC TODAY AS COMPARED TO THE
WAY IT HAS BEEN MOST OF THE WEEK. THERE IS A STRONG UPPER LEVEL
LOW OVER THE CENTRAL BERING SEA WITH A HIGH AMPLITUDE RIDGE THAT
RUNS UP THE EASTERN GULF OF ALASKA AND THEN ALONG THE ALCAN BORDER
INTO THE INTERIOR OF THE STATE. THE JET STREAM RUNS FROM JAPAN TO
JUST SOUTH OF THE ALEUTIANS AND THEN WEAKENS AS IT RUNS ACROSS THE
ALASKA PENINSULA AND SOUTHWEST ALASKA BETWEEN THE UPPER LEVEL LOW
AND RIDGE

THE SURFACE MAP HAS THE LARGE 965 MB LOW IN THE CENTRAL BERING
SEA WHICH IS THE LOW THAT REMAINS FROM THE MERGING OF THE EXTRA
TROPICAL LOW WITH THE OLD BERING SEA LOW. THE MAIN FRONT EXTENDS
OUT OF THIS LOW AND ACROSS SOUTHWEST ALASKA AND THEN INTO THE
WESTERN GULF OF ALASKA. THERE ARE A NUMBER OF WAVES AHEAD OF THIS
FRONT THAT ARE MOVING THROUGH SOUTHWEST AND SOUTHCENTRAL ALASKA
TODAY WHICH ARE PRODUCING ENHANCED RAINFALL AS THEY PASS THROUGH.

&&

.MODEL DISCUSSION...
SINCE THE MODELS LOCKED INTO THE MOVEMENT OF THE OLD EXTRA
TROPICAL SYSTEM MOVING INTO THE BERING SEA THEY HAVE HAD A NUMBER
OF VERY GOOD RUNS IN A ROW. THEY ARE ALL SHOWING THE SAME MOVEMENT
OF THE FEATURES WITH THE NAM BEING FAVORED DUE TO ITS RESOLUTION
AND ABILITY TO HANDLE THE TERRAIN.

&&

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
A LOT OF RAINFALL IS HEADING INTO THE AREA IN CONJUNCTION WITH THE
WEATHER FRONT. HEAVIEST RAINFALL WILL BE FROM THIS AFTERNOON
THROUGH TOMORROW MORNING IN THE EASTERN KENAI PENINSULA AND IN
NORTHERN PRINCE WILLIAM SOUND. A SMALL STREAM FLOOD ADVISORY HAS
BEEN ISSUED FOR THE SEWARD AREA FROM THE 5 INCHES OF RAINFALL THAT
IS EXPECTED IN THAT REGION.
STRONG WINDS ARE EXPECTED THROUGH CHANNELED TERRAIN ACROSS
SOUTHCENTRAL ALASKA THROUGH THE NIGHT WITH THE STRONGEST WINDS
BEING IN TURNAGAIN ARM AND THE HIGHER ELEVATIONS OF THE ANCHORAGE
HILLSIDE WHERE THERE IS A HIGH WIND WARNING IN EFFECT THROUGH THE
NIGHT. THE REMAINDER OF THE ANCHORAGE AREA INCLUDING THE LOWER
ELEVATIONS OF THE ANCHORAGE HILLSIDE WILL LIKELY SEE A MUCH
SHORTER DURATION OF WINDS AS WELL AS WINDS THAT ARE NOT AS STRONG
AS TURNAGAIN ARM. WINDS IN THE LOWER HILLSIDE ARE EXPECTED TO GUST
CLOSE TO 50 MPH WITH OCCASIONAL GUSTS TO 35 MPH AROUND THE REST OF
THE ANCHORAGE BOWL.

SOUTHWEST ALASKA...
STRONG WINDS AND HEAVY RAIN WILL IMPROVE BY LATE IN THE EVENING AS
THE FRONT PASSES NORTH OF THE REGION. ANOTHER OCCLUDED FRONT
ASSOCIATED WITH THE BERING SEA LOW WILL MOVE INTO THE AREA
SATURDAY EVENING AND BRING MORE WINDS AND RAIN...BUT NOT AS MUCH
AS TODAY.

BERING SEA/ALEUTIANS...
THE LARGE LOW WILL BRING HIGH WINDS TO THE CENTRAL ALEUTIAN
ISLANDS TONIGHT AND SOME VERY GUSTY WINDS TO THE DUTCH HARBOR
AREA. THESE WINDS IN THE DUTCH HARBOR AREA WILL BE RATHER LONG IN
DURATION AND ONCE THEY INCREASE THEY WILL PERSIST INTO SUNDAY
MORNING. THE ALASKA PENINSULA AND COLD BAY WILL ALSO SEE STRONG
WINDS AND HEAVY RAIN WITH THIS STRONG LOW.

&&

.LONG TERM FORECAST...
MODELS HAVE COME INTO BETTER AGREEMENT OVER THE PAST 24 HOURS ON
THE EVOLUTION OF THE BERING LOW BY EARLY NEXT WEEK...WITH THE GFS
FINALLY FALLING IN LINE WITH THE EC SOLUTION IN BRINGING THE LOW
NORTHWARD TO THE VICINITY OF THE KUSKOKWIM DELTA ON MONDAY. THE
LOW WILL THEN RETROGRADE WESTWARD INTO THE EASTERN BERING AND
REMAIN THERE THROUGH MUCH OF NEXT WEEK AS A STOUT UPPER RIDGE
PERSISTS OVER WESTERN CANADA. THE END RESULT WILL BE A
CONTINUATION OF THE WET PATTERN ACROSS THE SOUTHERN MAINLAND AS
MOIST SOUTHERLY FLOW BETWEEN THESE TWO LONGWAVE FEATURES REMAINS
FOCUSED ON THE NORTHERN GULF COAST. MEANWHILE...A SHOWERY PATTERN
WILL PREVAIL OVER MUCH OF THE BERING BENEATH THE BROAD UPPER
TROUGH.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WARNING 101 187.
         FLOOD ADVISORY 125.
MARINE...GALE 150-165 171 172 177-180 185.
		 STORM 170 173-176.
FIRE WEATHER...NONE.

&&

EZ/CB SEP 14