Small Craft Advisory 773, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM ADT TUE AUG 29 2006

.DISCUSSION...

...SUMMARY...
FOR TODAY...THERE IS A RIDGE OF HIGH PRESSURE OVER MAINLAND
ALASKA...AND A TROUGH OVER THE BERING SEA. THERE ARE TWO SURFACE
LOWS THIS MORNING...ONE IN THE NORTHERN BERING NEAR SAINT MATTHEW
ISLAND AND ANOTHER IN THE THE SOUTHERN BERING JUST NORTH OF ATKA.
THE NORTHERN LOW IS EXPECTED TO DISSIPATE TODAY...WHILE THE SOUTHERN
LOW STRENGTHENS RATHER RAPIDLY TODAY INTO WEDNESDAY BECAUSE OF ITS
MORE FAVORABLE UPPER LEVEL SUPPORT ON THE FRONT LEFT QUADRANT OF THE
JET STREAM. THE SOUTHERN LOW WILL MOVE FROM ATKA TODAY AT 1004 MB TO
BRISTOL BAY AT AROUND 993 MB BY WEDNESDAY. A WARM FRONT WILL MOVE
THROUGH THE GULF OF ALASKA AHEAD OF THE LOW PRESSURE TONIGHT INTO
WEDNESDAY...AND BY LATE WEDNESDAY...ANOTHER SURFACE LOW WILL FORM
AROUND KODIAK ISLAND. FROM WEDNESDAY NIGHT THROUGH SATURDAY...THE
LOW WILL HANG AROUND THE GULF OF ALASKA...WHILE A RIDGE WILL BE
POSITIONED OVER THE WESTERN BERING/ALEUTIANS.

...MODELS...
NAM/WRF MODEL IS OUT TO LUNCH AGAIN WITH HORRIBLE INITIALIZATION OF
THE TWO LOWS OVER THE BERING...AND WILL BE FAVORING THE OTHER MODEL
SOLUTIONS WHICH ARE IN REASONABLE AGREEMENT. NAM/WRF IS THE ODDBALL
MODEL FROM TODAY THROUGH WEDNESDAY MORNING WITH THE TRACK OF THE LOW
PRESSURE...BUT INTERESTINGLY THEN CONVERGES FAIRLY WELL WITH THE
OTHER MODELS IN THE LATTER PERIODS.

...SOUTHCENTRAL ALASKA/KODIAK ISLAND FORECAST...
ANOTHER TRANQUIL DAY IN STORE TODAY OVER SOUTHCENTRAL...WITH THE
RIDGE AXIS OVERHEAD OR SLIGHTLY TO THE WEST OF THE AREA. THERE WILL
PROBABLY BE LESS AFTERNOON CONVECTIVE SHOWER ACTIVITY THAN THE LAST
TWO DAYS...NOT THAT THERE WAS THAT MUCH ACTIVITY THE LAST TWO DAYS.
THE MAIN CONCERN OVER SOUTHCENTRAL TODAY IS FOG THIS MORNING. WITH
LIGHT WINDS AND ABUNDANT SOIL MOISTURE FOG COULD CERTAINLY BE AN
ISSUE IN THE VALLEYS WHERE SKIES ARE CLEAR THIS MORNING.
TEMPERATURES VARY WIDELY THIS MORNING WITH COLDER 30S IN OUTLYING
VALLEYS AND SINKS WITH CLEAR SKIES...BUT SOME 50S IN CLOUDIER AREAS
OR AREAS WITH WINDS. CASE IN POINT...IN PORTAGE VALLEY IT IS IN THE
MID TO UPPER 30S...WHILE WHITTIER IS HOVERING AROUND 60F DUE TO
LOCAL WINDS. A WARM FRONT AHEAD OF THE APPROACHING LOW PRESSURE TO
HIT KODIAK TONIGHT...AND THE GULF COAST ON WEDNESDAY...WITH SOME
ASSOCIATED GALES. SOME HEAVIER RAINFALL TOTALS CAN BE EXPECTED NEAR
THE COAST AND FOR KODIAK. WITH FAIRLY STRONG SOUTHEASTERLY FLOW WITH
THIS SYSTEM...DOWNSLOPE WILL BE SIGNIFICANT FOR THE WESTERN
KENAI...ANCHORAGE BOWL...AND INLAND AREAS. DO NOT EXPECT MUCH MORE
THAN LIGHT RAIN OR SPRINKLES FOR ANCHORAGE WITH THIS SYSTEM. THERE
IS THE LIKELIHOOD OF TURNAGAIN ARM WINDS APPROACHING 45 MPH
BEGINNING WEDNESDAY MORNING. ANOTHER CHALLENGE FOR SOUTHCENTRAL
FORECAST COMES IN FIGURING OUT HOW LONG THE WET WEATHER STAYS. IT
APPEARS THAT THE LOW WILL HANG OUT OVER THE GULF FOR SEVERAL
DAYS...AT LEAST UNTIL SATURDAY...STEADILY WEAKENING. AT THIS POINT
IT LOOKS LIKE WET WEATHER WILL NEVER MAKE IT FAR INLAND...THOUGH
RAIN SHOULD PERSIST FOR SOME COASTAL AREAS INTO SATURDAY AND PERHAPS
SUNDAY.

...SOUTHWEST MAINLAND ALASKA/ALASKA PENINSULA FORECAST...
QUIET DAY TODAY OVER THE SOUTHWEST MAINLAND...WITH MAIN CONCERN
BEING MORNING FOG ESPECIALLY OVER INLAND AREAS. LOW OVER THE BERING
TO BEGIN TO BRING RAIN TO THE ALASKA PENINSULA AND COAST WEST OF
BETHEL BY LATE THIS AFTERNOON. AS THE LOW MOVES INTO BRISTOL BAY
TONIGHT AND STRENGTHENS...SIGNIFICANT RAIN WILL SPREAD INTO MOST OF
THE REST OF THE SOUTHWEST MAINLAND FOR TONIGHT AND WEDNESDAY. THE
RAIN MAY HAVE TROUBLE MAKING IT AS FAR NORTHEAST AS
MCGRATH...HOWEVER. THE RAIN SHOULD TAPER OFF FOR THURSDAY OVER MOST
AREAS AS THE LOW TRANSITIONS INTO THE GULF...THOUGH AREAS FROM KING
SALMON EAST MAY STILL GET WET. NORTHWESTERLY FLOW WILL PERSIST OVER
THE AREA THROUGH THE WEEKEND AS A LESS PROGRESSIVE PATTERN SETS
UP...WITH A NEARLY STATIONARY LOW OVER THE GULF OF ALASKA AND A
RIDGE OVER THE WESTERN BERING/WESTERN ALEUTIANS. OCCASIONAL
SHORTWAVES WILL DROP THROUGH THE NORTHWEST FLOW LATE IN THE WEEK
WITH SOME SMALL PRECIPITATION CHANCES.

...BERING SEA/ALEUTIAN ISLANDS FORECAST...
LOW PRESSURE WILL RACE FROM WEST TO EAST THROUGH THE ALEUTIANS TODAY
AND TONIGHT...STRENGTHENING ALL THE TIME. BY WEDNESDAY MORNING...THE
LOW WILL BE IN BRISTOL BAY AND WILL SLOW DOWN. MODERATE RAIN WITH
THE LOW WILL SPREAD THROUGH THE CENTRAL AND EASTERN ALEUTIANS TODAY.
ONE INCH TOTALS HAVE OCCURRED AROUND ATKA AND ADAK ALREADY WITH THIS
SYSTEM. SOUTHWESTERLY WINDS APPROACHING GALES ARE POSSIBLE ON THE
PACIFIC SIDE OF THE ALEUTIANS TODAY AND TONIGHT AS THE LOW RACES
EAST...WITH GALE WINDS MORE LIKELY ON THE BACK SIDE OF THE LOW
WEDNESDAY THROUGH THURSDAY IN NORTHWESTERLY FLOW IN THE EASTERN
BERING/EASTERN ALEUTIANS. HIGH PRESSURE WILL BUILD ON WEDNESDAY OVER
THE WESTERN ALEUTIANS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING 120 130 79 180 410.
FIRE WEATHER...NONE.

FOISY AUG 06