Small Craft Advisory 466, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT FRI MAY 30 2008

.MODEL DISCUSSION AND UPPER LEVELS...
MODELS IN GOOD AGREEMENT THROUGH EARLY NEXT WEEK. MODELS DEEPEN THE
LOW SOUTH OF THE ALEUTIAN CHAIN AS THE JET SUPPORT INCREASES. A
STRONG VORT MAX TO ROUND THIS LOW SUNDAY AND PUSH INTO THE GULF.
THIS EFFECTIVELY MOVES THE RIDGE IN THE GULF AND PANHANDLE INTO
BRITISH COLUMBIA BY MONDAY. A SURFACE LOW TO  HOWEVER...THE POLAR LOW
TO MOVE INTO THE BERING STRAIT EARLY NEXT WEEK IS THE PLACE WHERE THE
DIFFERENCES START TO SHOW UP. THE 12Z GFS DIGS THIS FEATURE FURTHER
SOUTH THAN OTHER MODEL SOLUTIONS. THEREFORE...THE FORECAST WAS NOT
CHANGED BEYOND DAY 3 SINCE IT REFLECTED THE LESS VIGOROUS SOLUTION
FAVORED BY THE 00Z ECMWF AND GFS ENSEMBLES.

MEAN TROUGH OVER THE BERING TO BE DIGGING OVER TIME THIS WEEKEND.
FLOW CURRENTLY OVER THE INTERIOR MORE ZONAL WILL BECOME MORE
MERIDIONAL NEXT WEEK. THE POLAR JET IS ACTIVE WITH MANY SYSTEMS
MOVING THROUGH NORTHERN ALASKA. SUBTROPICAL JET BRINGING SYSTEMS TO
THE SOUTH OF THE ALEUTIAN CHAIN. THE POLAR JET DROPS INTO THE BERING
AND DIGS INTO THE BERING SEA TROUGH EARLY NEXT WEEK. THIS WILL TURN
THE AIR MASS COLDER OVER THE BERING. HOWEVER...THE INTERIOR
TEMPERATURES WILL INCREASE DUE TO THE MORE MERIDIONAL FLOW.

.ANALYSIS...
LOW PRESSURE SYSTEM MOVING THROUGH THE ARCTIC WITH A LOW SOUTH OF
DUTCH HARBOR. HIGH PRESSURE EXTENDS FROM NORTHERN BERING TO THE
EASTERN GULF. GOOD DIFFLUENCE ALOFT CREATING LOTS OF HIGH AND MID
LEVEL CLOUDINESS SOUTH OF 61N WITH SUNNY SKIES UP TO THE BROOKS
RANGE. DRY AND WARM CONDITIONS INLAND BUT NOT DRY ENOUGH FOR SEVERE
FIRE WEATHER CONDITIONS TODAY. WINDS ARE NOT ALL THAT STRONG EXCEPT
ALONG THE CENTRAL AND EASTERN ALEUTIANS EXTENDING INTO THE CENTRAL
BERING WITH A LOW CENTERED SOUTH OF DUTCH HARBOR. SEA BREEZE TO TAKE
OVER THIS AFTERNOON ALONG THE NORTHERN GULF COAST AND COOK INLET
REGION.

.SHORT TERM FORECAST...
ALEUTIANS AND BERING...
THE LOW SOUTH OF DUTCH HARBOR TO DEEPEN AS JET SUPPORT ARRIVES
TONIGHT. THE LOW TO DEEPEN FARTHER AS A COUPLE VORT MAXES ROTATE INTO
THE LOW. A STRONGER FRONT WILL BE INITIATED AS WELL OVER THE EASTERN
ALEUTIANS SATURDAY AND INTO THE AKPEN SATURDAY NIGHT. THE FRONT WILL
BREAK UP OVER BRISTOL BAY WITH A FILLING LOW OVER THE CENTRAL
ALEUTIANS SUNDAY. WINDS AND PRECIPITATION WILL INCREASE ALONG THE
CENTRAL AND EASTERN ALEUTIANS TO THE AKPEN TONIGHT INTO SATURDAY
NIGHT. A VORT MAX WITHIN THE STRONGER JET TO ROUND THE LOW SUNDAY
INTO THE WESTERN GULF AND LEAVE THE PARENT LOW TO FILL.

SOUTHWEST ALASKA...
A WEAK FRONT TO PUSH TO THE SOUTHWEST COAST TONIGHT WITH SOME
PRECIPITATION IN BRISTOL BAY TO THE SOUTHERN KUSKOKWIM DELTA. NO
PRECIPITATION IS EXPECTED TO PUSH OVER THE KUSKOKWIM VALLEY. MAYBE
SOME MOUNTAIN SHOWERS. HOWEVER...CLOUDS WILL KEEP TEMPERATURES DOWN
OVER THE KUSKOKWIM VALLEY. THIS WILL INCREASE RH VALUES A BIT INLAND
AND DRASTICALLY ALONG THE COAST TOMORROW. A STRONGER FRONT TO ARRIVE
SATURDAY NIGHT BUT WEAKEN QUICKLY SUNDAY. AGAIN NOT MUCH
PRECIPITATION TO MOVE INTO THE KUSKOKWIM VALLEY BUT A BIT MORE OF A
CHANCE THAN TONIGHT AND TOMORROW.

SOUTH AND EAST OF THE ALASKA RANGE...
WEAK RIDGE ALONG THE NORTHERN GULF COAST WITH AN APPROACHING WEAK
FRONT IN THE SOUTHWEST GULF BRINGING SOME LIGHT TO MODERATE WINDS
ALONG THE NORTHERN GULF COAST AND THROUGH EAST WEST ORIENTED GAPS.
OTHERWISE...SEA BREEZE WINDS KICKING IN ALONG COOK INLET AND PRINCE
WILLIAM SOUND. THE RIDGE ALONG THE COAST WILL NOT GO AWAY UNTIL
SUNDAY WHEN THE STRONGER FRONT IS EXPECTED TO MOVE INTO THE GULF.
UNTIL THEN...MODERATE EASTERLY WINDS EXPECTED ALONG THE COAST AND
EAST WEST ORIENTED GAPS. WITH THE FIRST FRONT TONIGHT AND
TOMORROW...MOST PRECIPITATION TO BE ALONG THE COAST WITH SOME
MOUNTAIN SHOWERS. RH VALUES WILL INCREASE QUITE A BIT EVERYWHERE
THOUGH WITH THE INCREASED CLOUD COVER AND SOME VIRGA POSSIBLE INLAND
OVER THE VALLEYS. THE NEXT FRONT ON SUNDAY TO INCREASE PRECIPITATION
AMD WINDS ALONG THE COAST. HOWEVER...PRECIPITATION INLAND WILL AGAIN
BE SPARSE. RH VALUES WILL INCREASE AGAIN AS WELL. THE LOW ROUNDING
THE CENTRAL ALEUTIAN LOW TO MOVE INTO THE GULF SUNDAY NIGHT WITH
WINDS AND PRECIPITATION CONTINUING TO INCREASE OVER THE GULF AND
COASTAL LOCATIONS.

.LONG TERM FORECAST...
OVERALL...BROAD TROUGH OVER THE BERING INTO THE MAINLAND. THIS WILL
LIKELY MEAN A SLIGHTLY COOLER PATTERN WITH SHOWERS OVER MUCH OF THE
AREA TUESDAY THROUGH FRIDAY.

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

JN MAY 08