Small Craft Advisory 489, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
349 AM ADT SAT JUN 14 2008

.ANALYSIS AND UPPER LEVELS...
THIS MORNING...AT UPPER LEVELS THERE IS A RIDGE AXIS OVER THE
EASTERN BERING/ALEUTIANS WITH THE CLOSED SURFACE AND UPPER LEVEL
HIGH FURTHER SOUTH IN THE NORTH PACIFIC. STRATUS AND FOG DOMINATE
THE CENTRAL TO EASTERN BERING/ALEUTIANS. A WEAK VERTICALLY STACKED
LOW IS MOVING SOUTHEAST THROUGH THE NORTHERN GULF OF ALASKA WITH
SHOWERS AND GENERALLY SUB-SMALL CRAFT WINDS. A WEAK NORTHEASTERLY
WAVE MOVING THROUGH SOUTHCENTRAL IS BRINGING SHOWER ACTIVITY TO THE
COOK INLET REGION THIS MORNING. A SURFACE THERMAL TROUGH REMAINS
FROM THE KUSKOKWIM VALLEY TO THE COPPER RIVER BASIN AND CONVECTION
WILL FORM ALONG IT AGAIN TODAY. A SURFACE LOW IS PASSING JUST WEST
OF ATTU TODAY...WITH RAIN AND WINDS TO GALE FORCE OVER THE WESTERN
ALEUTIANS.

.MODEL DISCUSSION...
MODELS ARE DOING NOT GREAT...NOT TERRIBLE...JUST OKAY. THERE ARE
SOME DISAGREEMENTS AS TO THE SPEED OF A LOW MOVING EAST ACROSS THE
SOUTHERN BERING AROUND MONDAY. THE 0Z OPERATIONAL GFS MAY BE
SLIGHTLY TOO FAST...AND WE ARE FAVORING A MORE COMPROMISE SOLUTION
AT THE MOMENT. MODELS ARE HAVING SOME TROUBLE ON THE SUBTLETIES OF
WEAK FLOW IN THE EXTENDED...AND USED A BLEND OF THE 0Z/12Z GFS FOR
THE FORECAST.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
A WEAK SHORTWAVE IN NORTHEAST FLOW HAS ALLOWED SHOWER ACTIVITY TO
PERSIST ALL NIGHT OVER THE COOK INLET REGION. MOST OF THE REMAINING
SHOWERS WITH THIS SHORTWAVE WILL BE FROM THE MATANUSKA VALLEY SOUTH
TO THE WESTERN KENAI PENINSULA THIS MORNING...TAPERING OFF FROM NORTH
TO SOUTH. THE THERMAL TROUGH PERSISTS OVER INLAND
SOUTHCENTRAL...WITH MORE OF THE TYPICAL AFTERNOON AND EVENING SHOWER
AND THUNDERSTORM ACTIVITY MAINLY OVER THE SUSITNA VALLEY AND COPPER
RIVER BASIN THROUGH MONDAY. PRECIPITATION WITH THE WEAK LOW OVER THE
GULF SHOULD REMAIN OVER THE GULF AS IT MOVES SOUTHEAST AND OUT OF
THE AREA. WEAK HIGH PRESSURE BUILDS OVER THE NORTHERN GULF TONIGHT
AND AS A RESULT SOUTHWEST FLOW WILL BE PRESENT OVER THE NORTHWEST
CORNER OF THE GULF...THUS WE WILL HAVE TO WATCH FOR OCCASIONAL LOW
CLOUDS OVER THE GULF SNEAKING INTO PORTIONS OF SOUTHCENTRAL NEAR THE
WATER MAINLY DURING THE MORNING HOURS. GENERALLY
THOUGH...TEMPERATURES WILL BE RISE A BIT OVER THE NEXT FEW DAYS WITH
A LITTLE MORE SUNSHINE FOR MOST AREAS.

SOUTHWEST MAINLAND...
SOME AFTERNOON SHOWERS AND STORMS WILL FORM AGAIN TODAY ALONG THE
THERMAL TROUGH MAINLY OVER INLAND PORTIONS OF BRISTOL BAY AND OVER
THE KUSKOKWIM VALLEY. HOWEVER...SOME CHANGES ARE UNDERWAY IN THE
PATTERN FOR THE SOUTHWEST MAINLAND. ALREADY...DENSE FOG HAS RETURNED
TO MEKORYUK AND IMMEDIATE COAST FROM CAPE NEWENHAM NORTH. THE LOW
CLOUDS AND FOG WILL MOVE INLAND TOWARD BETHEL THIS EVENING...AND A
COLD FRONT MOVING IN FROM THE NORTHWEST ON SUNDAY WILL BRING THE
MORE MOIST AIRMASS AND COOLER TEMPERATURES TO THE ENTIRE REGION.
THERE ARE ALSO LOW CLOUDS AND FOG IN EASTERN PORTIONS OF BRISTOL BAY
THIS MORNING...AND THESE SHOULD PERSIST FOR THE NEXT FEW DAYS AS
WELL. THERE MAY STILL BE A FEW STORMS ALONG THE ALASKA/ALEUTIAN
RANGE ON SUNDAY...BUT THUNDERSTORM ACTIVITY SHOULD GO AWAY ENTIRELY
ON MONDAY AS THE THERMAL TROUGH MOVES EAST OF THE AREA.

BERING SEA/ALEUTIANS...
LOW CLOUDS AND FOG DOMINATE THE CENTRAL TO EASTERN BERING/ALEUTIANS
WITH A RIDGE OF HIGH PRESSURE IN PLACE. THESE CONDITIONS ARE
EXPECTED TO PERSIST. AN AREA OF LOW PRESSURE PASSING JUST WEST OF
ATTU IS BRINGING RAIN AND GALE FORCE WINDS TO THE WESTERN ALEUTIANS
TODAY. THE FRONT ASSOCIATED WITH THE LOW DISSIPATES AS IT MOVES EAST
TOWARD THE EASTERN BERING RIDGE ON SUNDAY. ON MONDAY...A NEW LOW
PRESSURE INTENSIFIES SOUTH OF AMCHITKA AND MOVES INTO THE SOUTHERN
BERING...PERHAPS FINALLY BREAKING DOWN THE EASTERN BERING RIDGE.

.LONG TERM FORECAST...
THE EASTERN BERING RIDGE SHOULD BREAK DOWN MONDAY INTO TUESDAY WITH
ZONAL FLOW OR A WEAK MEAN TROUGH SETTING UP OUT WEST. IN
RESPONSE...A WEAK RIDGE IS EXPECTED TO BUILD OVER SOUTHCENTRAL WITH
A CONTINUATION OF AFTERNOON/EVENING CONVECTION INLAND ALONG WITH
TEMPERATURES NEAR OR SLIGHTLY ABOVE NORMAL.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE WARNING ZONE 176.
FIRE WEATHER...NONE.

FOISY JUN 08