Small Craft Advisory 704, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
400 AM AKDT MON SEP 15 2008

.ANALYSIS AND UPPER LEVELS...
A FAIRLY BENIGN SETUP ACROSS THE FORECAST AREA THIS MORNING COMPARED
TO PREVIOUS DAYS AND THE DAYS TO COME. THE MAIN FEATURE THIS MORNING
WITHIN THE FORECAST AREA IS A WEAK NEARLY STATIONARY VERTICALLY
STACKED LOW JUST OFF THE SOUTHWEST COAST. SCATTERED SHOWERS SURROUND
THE LOW FROM THE EASTERN BERING TO THE SOUTHWEST MAINLAND AND EAST
INTO SOUTHCENTRAL. TWO SURFACE LOWS ARE APPROACHING THE REGION FROM
THE WEST...ONE IN THE FAR WESTERN BERING MOVING EAST AND THE OTHER
SOUTHWEST OF THE WESTERN ALEUTIANS MOVING EAST. THE LATTER LOW IS
THE STRONGER LOW BECAUSE OF MORE UPPER LEVEL JET SUPPORT. ANOTHER
LOW IS INTENSIFYING SOUTH OF THE GULF OF ALASKA AND MOVING NORTH
TOWARD THE WEST CENTRAL GULF.

.MODEL DISCUSSION...
0Z MODELS ARE IN GOOD AGREEMENT THROUGH ABOUT WEDNESDAY AFTERNOON
AND THEN BEGIN TO DIVERGE. ALTHOUGH MODEL AGREEMENT IS GOOD IN THE
SHORT TERM...RUN TO RUN CONSISTENCY HAS NOT BEEN THAT GREAT IN
PARTICULAR WITH THE LOW MOVING NORTH IN THE GULF OF ALASKA. THEY
SEEM TO BE SETTLING ON A SOLUTION WHICH TAKES THE LOW NORTH JUST
WEST OF MIDDLETON ISLAND AND INTO PRINCE WILLIAM SOUND.

MODELS ARE STILL HAVING SOME TROUBLE AND SIGNIFICANT RUN TO RUN
INCONSISTENCIES IN THE EXTENDED. FOR THE LOW RIDING EAST JUST SOUTH
OF THE ALEUTIANS TUESDAY AND WEDNESDAY...MOST MODELS HAVE THE SAME
BASIC IDEA OF BRINGING IT INTO THE WESTERN GULF OF ALASKA THURSDAY
AND FRIDAY. STILL UNSURE WHERE THIS LOW WILL GO INTO NEXT
WEEKEND...HOWEVER. MODELS ALL GENERALLY BUILD HIGH PRESSURE INTO THE
BERING THURSDAY INTO NEXT WEEKEND. LAST FEW MODEL RUNS HAVE KEPT OLD
TYPHOON SINLAKU SOUTH OF OUR FORECAST AREA IN THE EXTENDED...BUT
STILL WILL HAVE TO KEEP AN EYE ON IT.

.SHORT TERM FORECAST...
SOUTHCENTRAL...
LIGHT BUT FAIRLY MOIST ONSHORE FLOW WILL PERSIST OVER SOUTHCENTRAL
TODAY WITH SOME LINGERING SHOWERS...WITH A WEAK SHORTWAVE RIDGE OF
HIGH PRESSURE BUILDING IN TONIGHT. THE MAIN STORY IS A NEW LOW WHICH
WILL STRENGTHEN AND MOVE NORTH INTO GULF TONIGHT. THE LOW WILL REACH
PRINCE WILLIAM SOUND TUESDAY NIGHT. WINDS WITH THIS LOW WILL NOT BE
TERRIBLY STRONG...GENERALLY SMALL CRAFT. HOWEVER...RAINFALL LOOKS TO
BE FAIRLY ABUNDANT OVER SOUTHCENTRAL...INCLUDING INLAND AREAS
BECAUSE OF FAIRLY LIGHT WINDS WITH THE SYSTEM HELPING TO LESSEN THE
DOWNSLOPING. RAIN SHOULD BEGIN OVER MAINLAND SOUTHCENTRAL LATE
MONDAY NIGHT OR TUESDAY MORNING. THIS LOW MOVES INLAND AND
DISSIPATES WEDNESDAY...BUT ANY BREAK IN THE UNSETTLED CONDITIONS
WILL LIKELY BE SHORTLIVED AS ANOTHER LOW PRESSURE MOVES EAST INTO
THE WESTERN GULF WED AFTERNOON OR EVENING.

SOUTHWEST MAINLAND...
MOSTLY CLOUDY SKIES WITH GENERALLY SCATTERED SHOWERS WILL PERSIST
OVER THE SOUTHWEST MAINLAND FOR THE NEXT FEW DAYS. THE AREA WILL BE
IN BETWEEN WEAK LOW PRESSURE IN THE EASTERN BERING AND LOW PRESSURE
IN THE GULF OF ALASKA/SOUTHCENTRAL...BUT THERE WILL STILL BE ENOUGH
MOISTURE AROUND FOR RAIN CHANCES TO CONTINUE.

BERING SEA/ALEUTIANS...
COMPLEX PATTERN IN THE BERING/ALEUTIANS THROUGH MIDWEEK. ONE LOW
PRESSURE SYSTEM IN THE FAR WESTERN BERING TODAY WILL MOVE EAST
TOWARD THE PRIBILOFS. A STRONGER LOW WITH A TRIPLE POINT DEVELOPING
WILL SKIRT JUST SOUTH OF THE ALEUTIANS. MOST OF THE ENERGY WITH THE
BERING LOW WILL BE ABSORBED INTO THE OTHER LOW ON WEDNESDAY AS IT
PASSES SOUTH OF THE ALASKA PENINSULA. NEITHER OF THE LOWS ARE
EXPECTED TO BE TERRIBLY STRONG WITH WINDS PROBABLY STAYING BELOW
GALE FORCE THROUGH MIDWEEK.

.LONG TERM FORECAST...
LOW PRESSURE IN THE GULF FOR THURSDAY AND FRIDAY WITH UNSETTLED
WEATHER EXPECTED ACROSS SOUTHCENTRAL. HIGH PRESSURE IS EXPECTED TO
BUILD INTO THE BERING THURSDAY AND FRIDAY.

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

FOISY SEP 08