Small Craft Advisory 409, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM ADT WED MAY 7 2008

.ANALYSIS AND UPPER LEVELS...
A STACKED LOW OVER THE CENTRAL ALEUTIANS CONTINUES TO BE THE FOCUS
FOR THE WEATHER. A STRONG FRONT IS SITUATED ALONG THE SOUTHWEST COAST
INTO THE GULF ACROSS KODIAK ISLAND THIS AFTERNOON. A RIDGE IS PRESENT
ALONG THE PANHANDLE TO THE NORTHERN GULF COAST. A WEAK THERMAL TROUGH
NEAR THE CANADIAN BORDER IN CENTRAL ALASKA MAY BECOME THE FOCUS FOR
CONVECTION ONCE AGAIN THIS AFTERNOON AND EVENING. A SECONDARY UPPER
LEVEL WAVE IS ROTATING AROUND THE STACKED LOW INTENSIFYING THE FRONT
IN THE GULF AREA. THIS WAVE WILL PUSH THE FRONT TO THE NORTHERN COAST
TONIGHT.

.MODEL DISCUSSION...
NUMERICAL MODELS ARE IN REASONABLE AGREEMENT THROUGH FRIDAY. NAM AND
GFS INITIALIZED FAIRLY WELL. HOWEVER...IT SEEMS THE NAM IS HANDLING
THE INTENSITY OF THE SOUTHERN GULF TRIPLE POINT LOW BETTER. BEYOND
THIS...THE MODELS ARE FAIRLY SIMILAR THROUGH FRIDAY. THE OUTLIERS IN
THE SOLUTION TEND TO BE THE 12Z RUNS OF THE UKMET AND GFS. THE
FORECAST HAS LEANED TOWARD THE 00Z ECMWF AND GFS SOLUTIONS BEYOND
FRIDAY MORNING AS THE UNCERTAINTY INCREASES DRAMATICALLY.

.SHORT TERM FORECAST...
SOUTH AND EAST OF THE ALASKA RANGE...
A WEAK FRONT IN THE WESTERN GULF IS BEING RE-INVIGORATED WITH A SHORT
WAVE AND SUPPORTIVE JET. THIS FRONT TO PUSH TO THE NORTHERN COAST
TONIGHT. AHEAD OF THE FRONT A RIDGE OF HIGH PRESSURE IS ALONG THE
COAST. COMBINED WITH THE INCREASING SOUTHEAST WINDS ALOFT...SOME
MODERATE TO STRONG WINDS WILL BE PRESENT ALONG THE COAST AND
EAST-WEST ORIENTED GAPS THROUGH TOMORROW. COMBINED WITH DRY AIR
INLAND...HAVE ISSUED A RED FLAG FOR THE MATANUSKA VALLEY. MAY NEED
THIS AGAIN TOMORROW. MOST OF THE PRECIPITATION WITH THIS FRONT WILL
BE ALONG THE COAST AND THE TYPICAL DOWNSLOPE TO OCCUR FROM PALMER TO
NEAR HOMER. SOME PRECIP TO SPREAD INTO THE SUSITNA VALLEY AND COPPER
RIVER BASIN...BUT MAINLY AT HIGH LEVELS. A SECONDARY LOW TO WRAP INTO
THE GULF THURSDAY NIGHT INTO FRIDAY. THIS WILL SUBSIDE THE EAST WEST
GAP WINDS BUT MODERATE TO STRONG EASTERLY WINDS WILL CONTINUE ALONG
THE COAST AND IN THE GULF. PRECIP TO REMAIN OVER KODIAK THROUGH
FRIDAY WITH MODERATE WINDS. COOK INLET WINDS WILL LIKELY BE STRONG
THURSDAY WITH THE NEXT LOW.

SOUTHWEST MAINLAND...
THE FRONT FROM THE STACKED LOW IN THE CENTRAL BERING TO REMAIN OVER
THE WEST COAST THROUGH THURSDAY. SOME DOWNSLOPE WILL BE PRESENT ALONG
THE ALEUTIANS THROUGH THURSDAY. THE STACKED LOW WILL BE PULLED EAST
AND WEAKEN WITH THE DEVELOPING GULF LOW THURSDAY NIGHT THROUGH
FRIDAY. SHOWERS WILL SPREAD FURTHER INLAND FRIDAY AS THE STACKED LOW
MOVES TOWARD THE KUSKOKWIM DELTA.

BERING SEA AND ALEUTIANS...
RAIN SHOWERS WILL CONTINUE OVER THE AREA THROUGH FRIDAY AS THE
STACKED LOW SLOWLY MOVES TOWARD THE COAST. MODERATE WINDS TO REMAIN
THROUGH THURSDAY BEFORE THE LOW WEAKENS FURTHER THURSDAY NIGHT AND
FRIDAY. COLDER AIR ON THE BACKSIDE OF THE LOW MAKING FOR RAIN AND
SNOW SHOWERS.

.LONG TERM FORECAST...
THE UNCERTAINTY IN THE FORECAST IS DERIVED FROM THE HANDLING OF A
SHORT WAVE TROUGH DEVELOPING INTO A CLOSED LOW NEAR THE CENTRAL
ALEUTIANS. THE NEWEST RUNS OF THE GFS HAVE THIS LOW SPREADING INTO
THE GULF WHEREAS THE 00Z RUNS HAD THE LOW WRAPPING BACK INTO BRISTOL
BAY AREA AND REMAINS THERE THROUGH MID WEEK. FORECAST AND HPC
GUIDANCE ARE LEANING TO THE 00Z RUNS.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...FLOOD ADVISORY ZONE 141
MARINE...GALE 130 132 138
FIRE WEATHER...RED FLAG WARNING ZONE 111

JN MAY 08