Small Craft Advisory 538, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
218 PM AKDT MON SEP 12 2011

.SHORT TERM...MAP ANALYSIS: HIGH PRESSURE IS OVER NORTHWEST
CANADA. A WEAK LOW IS ROUGHLY 53N/147W A WEAKENING WEATHER FRONT
EXTENDS FROM THE WEST CENTRAL GULF TO WEST OF HAIDA GWAII. A
SECOND LOW IS NEAR COLD BAY WITH AN EXTENSION TO IS PARENT LOW
NEAR 60N/180. THE FRONT WITH THE LOW NEAR COLD BAY EXTENDS SOUTH
INTO THE NORTH PACIFIC.

 FORECAST REASONING: / THROUGH TUESDAY AFTERNOON / THE LOW IN THE
SOUTHWEST GULF (53N/147W) IS EXPECTED TO DISSIPATE THROUGH MONDAY
EVENING AS THE UPPER LEVEL SUPPORT BREAKS DOWN INTO AN OPEN
TROUGH AND MOVES TO THE NORTHEAST GULF COAST BY TUESDAY MORNING
AND ONSHORE EARLY TUESDAY. JUST EXPECTED LIMITED RAIN WITH THIS
TROUGH...PRIMARILY WEST OF YAKUTAT BUT COULD BE REACHING AS FAR
EAST AS CAPE FAIRWEATHER. THE SECOND FRONT HAS MORE SUPPORT AND
WILL SWEEPING UP THE REMAINS OF THE FIRST SYSTEM WITH IT REACHING
THE CENTRAL GULF BY TUESDAY AFTERNOON.

 EXPECT THAT THE ONLY HAZARDS FOR TONIGHT AND TUESDAY WILL BE
SOME SMALL CRAFT LEVEL WINDS ON THE OUTSIDE...ALTHOUGH A SMALL
AREA OF GALE FORCE WINDS ARE EXPECTED NEAR CAPE SUCKLING ON
TUESDAY.

 &&

 .LONG TERM...TUES NIGHT THROUGH SUN NIGHT. EXTENDED FORECAST
CONTINUES TO LOOK WET WITH A FEW TROUGHS OR FRONTS MOVING THROUGH
THE AREA. THE FIRST OF WHICH SHOWS UP FOR EARLY WED BRINGING RAIN
AND WIND WITH IT. NOT EXPECTING MUCH MORE THAN SMALL CRAFT WINDS
OUT OF IT IN THE OFFSHORE AND CLARENCE STRAIT. RAIN MAY NOT BE
TOO BAD EITHER AS THE FRONT WILL BE WEAKENING OVER TOP OF THE
PANHANDLE. THE CAUSE OF THIS IS THAT IT WILL BE PUSHING AGAINST
THE UPPER RIDGE THAT HAS BEEN GIVING US THE GOOD WEATHER FOR THE
PAST FEW DAYS. IT WILL SUCCEED AT BOOTING THE RIDGE OFF TO THE
EAST.

 BEHIND THE FRONT, SW FLOW WILL SET UP FOR THE REST OF THE WEEK
AS A BROAD UPPER TROUGH PARKS ITSELF OVER WESTERN ALASKA. AT THE
SURFACE, ANOTHER FRONT WILL BE MAKING ITS WAY ACROSS THE GULF AND
WILL HIT THE PANHANDLE EARLY FRI. TIMING ISSUES REMAIN BETWEEN
THE MODELS FOR THIS FEATURE WITH THE EC BEING THE SLOWER
SCENARIO. AFTER THAT, THE MODELS ARE SUGGESTING THAT ANOTHER LOW
WILL SKIRT TO THE SOUTH OF THE PANHANDLE EARLY SAT.

 MODELS ARE IN FAIR AGREEMENT THROUGH ABOUT THURS WITH THE
EXCEPTION OF THE NAM FOR WED AND THUR. AT THAT TIME THE NAM IS AN
OUTLIER WITH A WEAK LOW OVER THE EASTERN GULF WHILE THE OTHER
MODELS DO NOT HAVE THIS FEATURE. DECIDED TO STICK WITH THE EC FOR
UPDATES WITH THE GFS A CLOSE SECOND. FARTHER OUT DECIDED TO USE
THE HPC GUIDANCE TO EVEN OUT THE DIFFERENCES THAT ARE SEEN IN THE
OPERATIONAL MODELS OUT THERE. FORECAST CONFIDENCE IS ABOVE
AVERAGE TO ABOUT THURS THEN DROPS TO SLIGHTLY BELOW AVERAGE AFTER
THAT POINT.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ052.
         SMALL CRAFT ADVISORY FOR PKZ022-043-051.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041-042.

&&

BEZENEK/EAL