Small Craft Advisory 800, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
255 PM ADT FRI SEP 28 2007

.MODEL DISCUSSION...
MODEL ARE IN GOOD AGREEMENT THROUGH TUESDAY. RUN TO RUN CONSISTENCY
IS GOOD AS WELL THROUGH THIS TIME FRAME. THE STRONG COLD CORE LOW
OVER THE WESTERN HEMISPHERE PORTION OF THE POLE TO SLOWLY SLIDE INTO
THE EASTERN HEMISPHERE THROUGH THE FOLLOWING WEEK. THE BIG DIFFERENCE
AT THIS TIME WOULD BE THE HANDLING OF A KAMCHATKA UPPER LOW AROUND
WEDNESDAY. THE GFS IS MUCH MORE NEGATIVELY TILTED WITH THIS LOW AND
SLOWER THAN THE EUROPEAN MODELS. THIS MAKES FOR A LESS AMPLIFIED
RIDGE OVER THE REMAINDER OF THE BERING AND WEAKER SURFACE SYSTEMS.
THIS REMAINS TRUE THROUGH THE REMAINDER OF THE WEEK.

UNTIL THEN...THE LARGE UPPER LOW OVER THE ALASKA PENINSULA MOVES
ACROSS THE GULF TOMORROW AND DEVELOPS INTO A TROUGH MOVING INTO THE
PANHANDLE SUNDAY. ANOTHER LOW OVER THE KAMCHATKA TO PUSH ACROSS THE
BERING AND INTO THE MAINLAND BY MONDAY. THIS LOW TURNS INTO A BROAD
TROUGH OVER THE MAINLAND INTO TUESDAY WITH A RIDGE OVER THE WESTERN
BERING BY TUESDAY.

.ANALYSIS...
VERTICALLY STACKED LOW OVER THE ALASKA PENINSULA WITH A TRIPLE POINT
LOW DEVELOPING NEAR KODIAK. THE NEW LOW IS PROVIDING A SOURCE FOR
STRONG WINDS IN THE GULF AND NEAR THE BARREN ISLANDS. IN
ADDITION...STRONG WINDS THROUGH THE GAPS ALONG THE KENAI PENINSULA.
THE WINDS HAVE LESSENED ALONG THE ALEUTIAN RANGE AS THE TRIPLE POINT
LOW HAS PICKED UP THIS AFTERNOON. THE ASSOCIATED FRONT WITH THIS LOW
IS PUSHING PRECIP OVER THE NORTHERN GULF INTO PRINCE WILLIAM SOUND
AND KENAI PENINSULA. LARGE AREAS OF DOWNSLOPE DRY SLOTS EVIDENT FROM
RADAR IMAGERY. FRONT QUITE VIGOROUS OVER THE NORTHERN GULF WITH A FEW
THUNDERSTORMS TODAY. WITH HIGH PRESSURE OVER THE WESTERN BERING...THE
PRESSURE GRADIENT BEHIND THE LOW COMBINED WITH GOOD COLD AIR
ADVECTION AND STRONG NORTHWEST JET IS PRODUCING STRONG NORTHWESTERLY
WINDS IN THE CENTRAL AND EASTERN BERING. ANOTHER LOW NEAR KAMCHATKA
BRINGING A FRONT TO THE WESTERN ALEUTIANS THIS AFTERNOON AND EVENING.

.SHORT TERM FORECAST...
BERING AND ALEUTIANS...
THE LARGE LOW NEAR KAMCHATKA TO PUSH INTO THE WESTERN BERING TONIGHT.
AN ASSOCIATED STRONG FRONT WITH GALE FORCE WINDS TO MOVE ACROSS THE
BERING TONIGHT AND INTO THE CENTRAL BERING SATURDAY. THE CLOSED LOW
ABOVE THE LOW OPENS AS A STRONG JET ROUNDS THE LOW. THE FRONT WORKS
TO THE COAST SATURDAY NIGHT WITH A BROAD TROUGH AND SURFACE LOW OVER
THE BERING. WINDS WILL DIMINISHIN TO THE SMALL CRAFT ADVISORY LEVEL
AS WELL. THE LOW CENTER TO MOVE EAST THROUGH SUNDAY WITH SHOWERS OVER
THE BERING. THE LOW TO MOVE INLAND MONDAY WITH SHOWERS ENDING FROM
THE WEST.

SOUTHWEST ALASKA...
LARGE LOW OVER THE ALASKA PENINSULA WITH RAIN OVER THE ENTIRE AREA
THIS EVENING. THE LOW TO MOVE INTO THE GULF WITH SHOWERS ENDING OVER
THE AREA LATE TONIGHT WITH HIGH PRESSURE TOMORROW. A STRONG FRONT TO
MOVE INTO THE COAST SATURDAY NIGHT WITH MODERATE WINDS ALONG THE
COAST. THE FRONT WILL WEAKEN AS IT MOVES INLAND THROUGH SUNDAY.
SHOWERS TO REMAIN OVER THE AREA AS THE MAIN LOW MOVES INLAND SUNDAY
NIGHT AND REMAINS OVER THE AREA INTO TUESDAY. AS HIGH PRESSURE BUILDS
OVER THE BERING...STRONG NORTHWEST WINDS TO DEVELOP ALONG THE COAST
MONDAY THROUGH TUESDAY.

SOUTH CENTRAL ALASKA...
STRONG FRONT ALONG THE NORTHERN GULF COAST THIS AFTERNOON WITH A
TRIPLE POINT LOW NEAR KODIAK. STRONG GRADIENT ALONG THE COAST WITH
MODERATE SOUTHEAST WINDS THROUGH 500 MB. STRONG WINDS AROUND THE LOW
NEAR KODIAK AS WELL PROMPTED PUSHING WINDS UP A BIT THIS MORNING.
PLENTY OF PRECIPITATION WITH THE FRONT...BUT STILL HAVE DRY LEE SIDE
AREAS ALONG THE KENAI INTO THE ANCHORAGE BOWL. THE FRONT IS
ASSOCIATED WITH A DEVELOPING LOW NEAR KODIAK AND ITS PARENT LOW IN
BRISTOL BAY. THE LOW NEAR KODIAK TO TAKE OVER AND SWING TO THE EAST
OVER NIGHT TO THE CENTRAL GULF. SHOWERS INLAND WILL PULL AWAY FROM
THE COAST TONIGHT AND THROUGH TOMORROW AS THE LOW PULLS TO THE
SOUTHEAST GULF. THERE WILL BE A BIT COOLER AIR MASS BUT DRY OVER THE
AREA SATURDAY. THE FRONT THAT MOVES INTO SOUTHWEST ALASKA SATURDAY
NIGHT TO STRETCH ACROSS SOUTH CENTRAL SUNDAY. A LOW TO DEVELOP ALONG
THIS FRONT IN THE WESTERN GULF SUNDAY NIGHT. THIS COULD PRODUCE
STRONGER WINDS IN THE GULF AS A RESULT ESPECIALLY AS IT DEEPENS IN
THE EASTERN GULF SUNDAY NIGHT. IN THE MEANTIME...SHOWERS WILL BE
POSSIBLE OVER MUCH OF SOUTH CENTRAL SUNDAY THROUGH MONDAY FROM THE
UPPER LOW MOVING OVER THE MAINLAND. THE LOW THAT DEVELOPED IN THE
GULF MOVES TO THE PANHANDLE MONDAY AND INLAND TUESDAY WITH MODERATE
TO STRONG NORTHWEST WINDS OVER THE GULF BEHIND THE LOW.

.LONG TERM FORECAST...
SHOWERY WEATHER GRADUALLY TAPERS OFF WEDNESDAY AS THE BROAD UPPER LOW
TRANSLATES SOUTHEASTWARD INTO THE EASTERN GULF AND DOWN THE PACIFIC
COAST TOWARDS WASHINGTON. NORTHERLY FLOW IN THE WAKE OF THIS SYSTEM
WILL BRING A COOLING TREND TO MAINLAND ALASKA INCLUDING SOUTH CENTRAL
BY THE MIDDLE OF NEXT WEEK. THE DRY NORTHERLY FLOW SHOULD RULE OUT
THE POSSIBILITY OF SNOW SHOWERS FOR NOW THOUGH. THE BERING SHOULD SEE
A PERIOD OF QUIETER WEATHER AFTER THE PASSAGE OF THE STORM SYSTEM
THIS WEEKEND AS A RIDGE BUILDS OVER THE REGION. HOWEVER...THERE IS A
GOOD DEAL OF UNCERTAINTY IN THE MODELS ACROSS THIS AREA NEXT WEEK.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALE 120 125 150 155 160 165 170 171 172 175 176 179 180
FIRE WEATHER...NONE

JN SEP 07