Small Craft Advisory 346, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
500 AM ADT FRI APR 13 2007

.ANALYSIS AND UPPER LEVELS...

CUT-OFF UPPER LEVEL LOWS SOUTHWEST OF SHEMYA AND OVER THE SOUTHERN
GULF THIS MORNING...WITH WEAK RIDGING JUST SOUTH OF THE EASTERN
ALEUTIANS AND A MORE SIGNIFICANT RIDGE OVER BRITISH COLUMBIA. AT THE
SURFACE...A TIGHTLY WOUND LOW IS WELL SOUTHWEST OF THE GULF AND A
COMPLEX LOW IS SOUTH OF THE ALEUTIANS EXTENDING WELL INTO THE NORTH
PACIFIC. A WEAK RIDGE IS OVER THE EASTERN ALEUTIANS.

.MODEL DISCUSSION...

MODELS ARE IN GOOD AGREEMENT IN BRINGING THE GULF LOW INLAND SAT
AFTERNOON OVER THE EXTREME SOUTHERN TIP OF SOUTHEAST AK...AND LEAVING
A WEAK TROUGH ALONG THE NORTH GULF COAST THROUGH SAT. IT IS IN THE
EVOLUTION OF THE COMPLEX LOW SOUTH OF THE ALEUTIANS WHERE UNCERTAINTY
EXISTS. THERE ARE DIFFERENCES IN HOW THE LOWS CONSOLIDATE INTO ONE
CENTER ALONG 50 N SOUTH OF KODIAK ISLAND SAT NIGHT. THE UKMET TRAILS
THE GFS SOLUTION INITIALLY...BUT COMES IN LINE SAT NIGHT...AND THE
NAM GENERALLY TAKES A SIMILAR TRACK. FOR COORDINATION PURPOSES THE
GFS SOLUTION WAS USED. THE THIRD LOW MOVING TOWARD THE WESTERN
ALEUTIANS FOR THE WEEKEND IS ALSO HANDLED WELL BY THE GFS.

.SHORT TERM FORECAST...

FOR THE BERING AND ALEUTIANS... THE COMPLEX LOW WILL BRING SNOW
SHOWERS...SMALL CRAFT AND GALES TO THE EASTERN ISLANDS AND AK PEN
TONIGHT THROUGH THE WEEKEND. THE NEXT LOW AFFECTS THE SAME AREA WITH
THE SAME CONDITIONS BEGINNING MON AND LASTING THROUGH WED.

FOR SOUTHWEST AK...WEAK IMPULSES MOVING AROUND THE GULF LOW MAY
TRIGGER UPSLOPE SHOWERS ON THE WESTERN SIDES OF THE ALASKA AND
ALEUTIAN RANGES THROUGH SAT...OTHERWISE MOST ACTIVITY ASSOCIATED WITH
THE LOW TRANSITING THE CHAIN OVER THE WEEKEND WILL AFFECT THE AKPEN
AND BRISTOL BAY WITH SHOWERS...AND PARTIAL CLEARING INLAND. RIDGING
AND DRY CONDITIONS DEVELOP BEFORE THE THIRD ALEUTIAN LOW ARRIVES BY
MIDWEEK WITH SHOWERS ONLY AFFECTING THE BRISTOL BAY ZONE.

IN THE EAST...THE LOCATION OF THE LOW OVER THE SOUTHERN GULF WILL
KEEP MOST OF THE SHOWER ACTIVITY ALONG THE NORTH GULF COAST THIS
WEEKEND...WITH ONLY ISOLATED ACTIVITY MAKING IT ACROSS THE CHUGACH
RANGE. A DECAYING TRIPLE POINT LOW ASSOCIATED WITH THE FIRST ALEUTIAN
LOW WILL KEEP SHOWERS ALONG THE NORTH GULF COAST INTO THE MIDDLE OF
NEXT WEEK.

.LONG TERM FORECAST...

OUT WEST...A THIRD LOW APPROACHES THE WESTERN ALEUTIANS WED. THIS HAS
THE POTENTIAL FOR BEING STRONGER THAN THE PREVIOUS TWO...WHICH MEANS
THE AREA OF GALE FORCE WINDS WILL ENCOMPASS A LARGER AREA FOR THE END
OF NEXT WEEK.

SOUTHWEST AK WILL HAVE SHOWERS ENDING BY THE END OF THE WEEKEND FROM
THE SECOND LOW WITH A BRIEF BREAK BEFORE LOW NUMBER THREE ARRIVES
LATE NEXT WEEK.

MOST OF THE EAST WILL HAVE IMPROVING CONDITIONS FOR THE END OF THE
WEEK AS LOW NUMBER TWO REMAINS WELL SOUTH OF THE AREA.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE
MARINE...GALES 155 172
FIRE WEATHER...NONE

DS APR 07