Small Craft Advisory 343, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT THU APR 12 2007

.MODEL DISCUSSION...

THERE ARE SEVERAL LOWS IN SERIES THAT WILL AFFECT THE FORECAST AREA
OVER THE NEXT WEEK. MODELS ARE IN GOOD AGREEMENT FOR THE FIRST COUPLE
OF DAYS BUT BY LATE SATURDAY THE GFS AND NAM ARE BOTH A BIT FASTER
THAN THE UKMET WITH A LOW SOUTH OF THE AKPEN. THE THIRD LOW
APPROACHES THE WESTERN ALEUTIANS SUNDAY AND THEN...ACCORDING TO THE
MULTIPLE RUNS OF THE GFS ENSEMBLE...LOSES DETAIL IN THE MIDST OF THE
SPAGHETTI PLOT. TO MAINTAIN SOME SEMBLANCE OF CONTINUITY THE CURRENT
FORECAST IS A BLEND OF THE PREVIOUS THINKING WITH THE OOZ GFS MODEL
RUN. IN THE EARLY PERIODS THIS MAKES LITTLE CHANGE...BUT AS THE
WEEKEND PROGRESSES THE BLEND RESULTS IN MORE SIGNIFICANT CHANGES TO A
FORECAST THAT HAD STAGNATED DUE TO PERSISTENT UNCERTAINTY.

.ANALYSIS AND UPPER LEVELS...

AT UPPER LEVELS OUR CORNER OF THE HEMISPHERE FEATURES A CUT-OFF LOW
WELL SOUTH OF KODIAK ISLAND AND AN OPEN TROUGH OVER THE EXTREME
WESTERN BERING. THE MAIN UPPER RIDGE IS OVER THE LOWER 48 WEST COAST
WITH WEAK RIDGES SOUTH OF THE CENTRAL ALEUTIANS AND OVER THE NORTHERN
ALCAN REGION.

AT THE SURFACE THE MAIN FEATURE IS THE TIGHTLY WOUND LOW SOUTH OF
KODIAK ISLAND.

.SHORT TERM FORECAST...

IN THE WEST WEAK LOW PRESSURE WILL PERSIST OVER THE AREA WITH
ISOLATED SHOWER ACTIVITY OVER THE BERING AND ALEUTIANS THROUGH
SUNDAY. AS THE SECOND LOW PASSES FAIRLY CLOSE TO THE AKPEN ON
SUNDAY...SMALL CRAFT AND GALES WILL AFFECT THE EASTERN BERING AND
ALEUTIANS AS FAR EAST AS BRISTOL BAY.

OVER SOUTHWEST AK...A FEW SHOWERS WILL DEVELOP ACROSS THE AREA
THROUGH SAT BEFORE A BREAK BETWEEN SYSTEMS OCCURS SUN.

IN THE EAST...THE WEATHER FRONT ASSOCIATED WITH THE LOW SOUTH OF
KODIAK WILL BRING RAIN TO KODIAK ON NORTHEAST FLOW THROUGH TONIGHT. A
WIND SHIFT TURNS PRECIPITATION TO SHOWERS WHICH DIMINISH BY FRIDAY
MORNING. DRY CONDITIONS WILL THEN PERSIST OVER THE ISLAND THROUGH
SAT.

SINCE THE FIRST LOW WILL MOVE ACROSS THE SOUTHERN GULF...THE NORTH
COAST WILL RECEIVE SHOWERS THIS AFTERNOON AND TONIGHT...ALONG WITH
SMALL CRAFT AND GALES AS THE FRONT MOVES INLAND. THE DECAYING FRONT
WILL BRING A FEW SHOWERS INLAND...ESPECIALLY NEAR THE CHUGACH AND
KENAI MOUNTAINS TONIGHT. SOME AFTERNOON SHOWERS ARE THEN POSSIBLE
INLAND FRI AND SAT.

.LONG TERM FORECAST...

IN THE WEST...AMIDST THE UNCERTAINTY THE THIRD LOW SEEMS TO BE
TRACKING JUST SOUTH OF THE ALEUTIANS MON WITH SMALL CRAFT AND GALES
LIMITED TO COASTAL WATERS OF THE CHAIN. BY MID WEEK THE LOW MOVES
INTO BRISTOL BAY WITH SNOW CHANGING TO RAIN MOVING INTO SOUTHWEST AK
TUE AND WED. IN THE EAST...MOST ACTIVITY REMAINS TO THE SOUTH SO
CONDITIONS SHOULD BE DRY EXCEPT FOR A FEW AFTERNOON SHOWERS INTO THE
MIDDLE OF NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 120 130 132 138 150 155
FIRE WEATHER...NONE

DS APR 07