Small Craft Advisory 416, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 PM ADT SUN MAY 6 2007

.MODEL DISCUSSION...
MODELS ARE IN GOOD AGREEMENT AND ACCEPTED. CHANGES THAT THE GFS MODEL
EXHIBITED OVER BERING SEA IN THE LAST FEW MODEL RUNS HAVE BEEN PICKED
UP BY THE UKMET AND THE NAM MODELS, SO THERE IS A HIGH CONFIDENCE IN
THE CHANGING TRENDS.

.ANALYSIS AND UPPER LEVELS...
THE UPPER LOW OVER THE GULF OF ALASKA CONTINUES TO WEAK AND WILL
DISSIPATE INTO A TROUGH OVER THIS AFTERNOON. AN UPPER SHORT WAVE OVER
THE ALASKA RANGE WILL CONTINUE TO MOVE EAST INTO SOUTH CENTRAL ALASKA
TONIGHT.

THE THERMAL TROUGH OVER SOUTHWEST ALASKA HAS DIMINISHED WITH COOLER
850 MB TEMPERATURES THAT MOVED INTO THE AREA OVERNIGHT. SOME CLEARING
OVER SOUTH CENTRAL ALASKA AND WARMING LOW LEVEL TEMPERATURES WILL
DESTABILIZE THE AIRMASS OVER THE NORTHERN SUSITNA VALLEY AND COPPER
RIVER BASIN THIS AFTERNOON AND EVENING. SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS OVER THE COPPER RIVER BASIN THIS EVENING.

.SHORT TERM FORECAST...
SOUTHCENTRAL ALASKA...
THE THERMAL TROUGH WILL REMAIN OVER THE COPPER RIVER BASIN THROUGH
TUESDAY WITH SHOWERS DEVELOPING IN THE AFTERNOON AND EVENING. THE
SHORT WAVE OVER THE ALASKA RANGE WILL WEAKEN OVER THE SUSITNA VALLEY
AND KENAI PENINSULA TONIGHT AND DISSIPATE MONDAY MORNING. SOME RAIN
IS EXPECTED OVER THE SUSITNA VALLEY WITH THIS WAVE, BUT REST OF THE
AREA WILL SEE INCREASING MID TO HIGH LEVEL CLOUDS TONIGHT AND MONDAY.

SOUTHWEST ALASKA...
ANOTHER SHORT WAVE IS EXPECTED TO MOVE THROUGH THE KUSKOKWIM DELTA
AND BRISTOL BAY TONIGHT AND MONDAY MORNING. THIS ONE WILL BRING A
LITTLE MORE RAIN AND SNOW ALONG THE COASTAL SECTIONS TONIGHT AND
EARLY MONDAY. OTHERWISE MOSTLY CLOUDY SKIES WILL CONTINUE OVER THE
REGION THROUGH TUESDAY.

BERING SEA...
A SHORT WAVE OVER THE WESTERN ALEUTIANS WILL MOVE ACROSS THE SOUTHERN
BERING SEA MONDAY NIGHT AND INTO THE ALASKA PENINSULA TUESDAY. AREAS
OF RAIN WILL MOVE ALONG THE ALEUTIAN CHAIN WITH SHORT WAVE. THE RIDGE
WILL BUILD BACK BEHIND THE WAVE MONDAY NIGHT AND TUESDAY.

ANOTHER LOW EAST OF HOKKAIDO WILL MOVE INTO THE KAMCHATKA PENINSULA
TUESDAY. GALE FORCE WINDS WILL DEVELOP OVER THE WESTERN ALEUTIANS
TUESDAY.

.LONG TERM FORECAST...
A BROAD AREA OF LOW PRESSURE WILL CONTINUE TO DOMINATE THE SOUTHERN
AND CENTRAL INTERIOR THROUGH THURSDAY. THE THERMAL TROUGH OVER THE
COPPER RIVER BASIN WILL EXTEND INTO THE KUSKOKWIM VALLEY AND BRISTOL
BAY AND SPREAD THE CONVECTIVE SHOWERS WESTWARD. THE OVER THE CENTRAL
BERING SEA WILL DEVELOP INTO A CUTOFF HIGH IN THE NORTHERN BERING
WEDNESDAY WILL DRIFT INTO THE CENTRAL BERING THURSDAY NIGHT.

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

NM MAY 07