Small Craft Advisory 730, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM AKDT TUE SEP 23 2008

.ANALYSIS AND UPPER LEVELS...

VERTICALLY STACKED LOWS OVER WESTERN AK AND THE WESTERN ALEUTIANS
THIS MORNING WITH RIDGES SOUTH OF THE EASTERN ALEUTIANS AND OVER
EASTERN RUSSIA.

.MODEL DISCUSSION...

MODELS ARE IN EXCELLENT AGREEMENT FOR THE FIRST THREE DAYS AND IN
SATISFACTORY AGREEMENT INTO THE WEEKEND. FROM THAT POINT MODEL
INSTABILITY IS HIGH AND FORECASTS FOR DAYS 6 AND 7 HAVE LOW
CONFIDENCE. IN THE SHORT AND MID TERM...THE ALEUTIAN LOW TRAVELS EAST
ALONG 50-53N WHILE THE WESTERN AK LOW MOVES INLAND AND THEN SOUTHEAST
TO THE AKPEN BY WED. AT THIS POINT THE TWO LOWS MERGE WELL SOUTH OF
KODIAK. THE NEWLY FORMED LOW THEN MOVES ACROSS THE GULF TO SOUTHEAST
AK BY THE WEEKEND. AT THE SAME TIME AS THE LOW MERGER...A WEATHER
FRONT FROM THE NEXT KAMCHATKA LOW WILL MOVE INTO THE WESTERN
ALEUTIANS TUE NIGHT AND REACH THE EASTERN ALEUTIANS THU NIGHT INTO
FRI. WHILE ALL THIS IS OCCURRING...WEAK RIDGING BUILDS OVER THE AK
MAINLAND. FORECASTS DEPEND HEAVILY ON THE GFS SOLUTION IN THE SHORT
TERM...BLENDING WITH THE EC IN THE MID AND LONG RANGE.

.SHORT TERM FORECAST...

IN THE WEST...THE LOW MOVING ALONG THE ALEUTIANS WILL BE PRECEDED BY
RAIN AND FOLLOWED BY SHOWERS THROUGH WED. HIGH PRESSURE WILL BUILD IN
BEHIND THE LOW BRINGING DRY CONDITIONS TO CENTRAL AND EASTERN
PORTIONS OF THE CHAIN THROUGH THU. THE NEXT WEATHER FRONT WILL BRING
RAIN AND GALES TO THE WESTERN AND CENTRAL ALEUTIANS THROUGH THU.

FOR SOUTHWEST AK...THE WESTERN AK LOW WILL BRING LOCALLY HEAVY
SHOWERS TO THE AREA TODAY...WHICH WILL DIMINISH IN INTENSITY WED. BY
THU THE LOW MERGES WITH THE ALEUTIAN LOW AND SHOWERS ARE LIMITED TO
THE AK AND ALEUTIAN RANGES.

SOUTH AND EAST OF THE AK RANGE...MOISTURE FROM THE WESTERN AK LOW
WILL BRING RAIN TO ALL BUT THE EASTERNMOST ZONES TODAY. HIGH PRESSURE
OVER THE ALCAN WILL LIMIT MOST PRECIPITATION IN THE COPPER RIVER ZONE
TO THE TALKEETNA AND CHUGACH MOUNTAINS. THIS COVERAGE PATTERN
PERSISTS THROUGH THU AS THE MERGER OF THE TWO LOWS OCCURS AND THE NEW
LOW MOVES INTO THE GULF.

.LONG TERM FORECAST...

IN THE WEST...A LOW FORMS ALONG THE FRONT AND RAIN SPREADS ACROSS
THE EASTERN ALEUTIANS INTO THE WEEKEND. DRYING CONTINUES INTO THE
WEEKEND FOR SOUTHWEST AK. PRECIPITATION ALONG THE NORTHERN FLANK OF
THE LOW IN THE GULF WILL BE LIMITED MAINLY TO COASTAL SECTIONS FOR
THE WEEKEND.

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

DS SEP 08