Small Craft Advisory 446, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT TUE MAY 31 2005

.DISCUSSION...

A MASSIVE VERTICALLY STACKED AND VIRTUALLY STATIONARY LOW PRESSURE
SYSTEM REMAINED CENTERED OVER ADAK THIS MORNING. WEAK TROUGHS
ASSOCIATED WITH THIS SYSTEM WERE BRINGING CLOUDS AND SHOWERS TO THE
AKPEN AND THE CENTRAL ALEUTIANS. FURTHER EAST...ONSHORE FLOW
PERSISTED ACROSS THE GULF COAST WITH PLENTY OF PRECIPITATION...MAINLY
ON COASTAL MOUNTAINSIDES. SOME PRECIPITATION CONTINUED TO BLEED
ACROSS THE KENAI AND INTO THE SUSITNA VALLEY.

MODELS ARE IN GOOD AGREEMENT THROUGH WEDNESDAY...SPINNING THE
ALEUTIAN LOW IN PLACE BEFORE BEGINNING TO BRING IT EAST. SOME
DEVIATION OCCURS AT THIS POINT WITH THE MESOETA BRINGING THE LOW
ACROSS THE GULF OF ALASKA WITH UNCHARACTERISTIC SPEED AND STRENGTH.
THE GFS IS A BIT SLOWER AND NOT AS STRONG. THESE DIFFERENCES
ESSENTIALLY AFFECT THE WESTERN GULF WIND FIELD. THE FORECAST REFLECTS
A COMPROMISE SOLUTION FOR DAYS 3 AND 4 WITH GFS TIMING AND A BIT MORE
WIND IN THAT AREA.

OTHERWISE SHOWERS WILL PERSIST ALONG THE GULF COAST THROUGH WEDNESDAY
AND THE AKPEN AND EASTERN ALEUTIANS THROUGH THURSDAY. INLAND...THE
THERMAL TROUGH IS SLOWLY MOVING SOUTH AND SHOULD CROSS THE ALASKA
RANGE WEDNESDAY...AND SETTLE OVER THE COPPER RIVER BASIN THURSDAY.
SHOWERS CAN BE EXPECTED DURING THIS PERIOD. THE BEST CHANCE FOR
SUBSTANTIAL CONVECTION APPEARS TO BE ASSOCIATED WITH THE REMNANTS OF
THE ALEUTIAN TROUGH WHEN IT CROSSES THE KENAI AND ANCHORAGE BOWL
THURSDAY AFTERNOON. THE THERMAL TROUGH MAY ALSO BE THE FOCUS OF SOME
ACTIVITY THURSDAY NEAR MCGRATH.

IN THE EXTENDED...THE LOW MOVING ACROSS THE GULF WILL KEEP ONSHORE
FLOW AND RAIN OVER THE WESTERN GULF COAST AND KODIAK ISLAND THROUGH
FRIDAY. HIGH PRESSURE WILL BUILD OVER THE REST OF THE GULF WHICH WILL
MIGRATE WEST FOR THE WEEKEND. AFTERNOON AND EVENING SHOWERS AND
POSSIBLE THUNDERSTORMS CAN BE EXPECTED INLAND THROUGH THE WEEKEND.

THE BERING AND ALEUTIANS SHOULD BE RAIN FREE FRIDAY...BUT THE NEXT
NORTH PACIFIC LOW WILL BRING RAIN AND A REPEAT OF CURRENT CONDITIONS
FOR THE BEGINNING OF NEXT WEEK.

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

DS MAY 05