Small Craft Advisory 565, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1140 AM AST THU NOV 22 2007

.SYNOPSIS...
.SHORT RANGE...THE LATEST SATELLITE IMAGERY SHOWS THE SOUTHERN
THIRD OF THE PANHANDLE PARTLY CLOUDY TO MOSTLY CLEAR WITH AREAS
OF FOG...WHICH WILL LIFT THROUGH THE MORNING HOURS. THE REST OF
THE PANHANDLE IS UNDER CLOUDY SKIES WITH CLOUDS MOVING IN FROM
THE WEST FROM THE APPROACHING WEATHER SYSTEM. THE WINDS OVER THE
AREA ARE FAIRLY LIGHT WITH THE STRONGEST WINDS OVER THE MARINE
AREAS AND WEST OF PAYA.

THE UPPER RIDGE OVER SE AK THIS MORNING WILL SLIDE TO THE EAST
THROUGH THE AFTERNOON AS AN TROF OVER THE WESTERN GULF DRIFT EAST
TO BE OVER THE CENTRAL GULF BY FRI AFTERNOON. THIS RIDGE WILL
KEEP THE SOUTHERN THIRD PARTLY CLOUDY THROUGH TODAY BUT AS THE
AXIS PASSES TO THE EAST CLOUDS WILL BEGIN TO ADVECT INTO THE AREA
THROUGH TONIGHT. BEFORE THE CLOUDS MOVE INTO THE AREA FOG WILL
FORM AGAIN THIS EVENING OVER THE SOUTHERN AREAS BUT BY FRI
MORNING MOST OF THE FOG SHOULD DISSIPATE WITH THE APPROACHING
TROF.

A 985MB LOW JUST SOUTH OF KODIAK ATTM WILL LIFT INTO WESTERN AK
THROUGH THE AFTERNOON. A WAVE ALONG THE FRONT WILL LIFT NE INTO
THE EASTERN GULF BY FRI AFTERNOON. USED A 50/50 BLEND OF THE 12Z
GFS40 AND THE UKMET AS IT SEEMS THAT THE GFS IS A BIT TO STRONG
IN DEVELOPING THIS WAVE/TROF. THIS WAVE/TROF WILL INCREASE THE
WINDS OVER THE NORTHERN GULF TO MAX GALES THIS EVENING WITH MIN
GALES EXTENDING INTO THE NE GULF TONIGHT. THE SE GULF WILL SEE
THE WINDS INCREASE TO MAX SMALL CRAFTS LATE TONIGHT. MOST OF THE
STRONG WINDS OVER THE GULF WILL DIMINISH THROUGH FRIDAY AS THE
WAVE/TROF WILL FURTHER WEAKEN.

THERE IS A WIND ADVISORY OUT FOR PAYA THROUGH 9AM FRI...WINDS
WILL INCREASE FROM THE WEST THIS EVENING THEN DRIFT EAST THROUGH
THE EARLY MORNING HOURS IN ASSOCIATION WITH THE TROF. THE WINDS
SHOULD DIMINISH THROUGH THE FRIDAY MORNING AS WITH THE WAVE
CONTINUING EAST. THE REST OF THE PANHANDLE WILL SEE GUSTY WINDS
ALONG THE COAST TO 30 MPH BUT THE INSIDE CHANNELS WILL JUST SEE
SOME BREEZY CONDITIONS IN EXPOSED AREAS THROUGH FRIDAY.

THE BIGGEST CHANGE THAT WILL HAPPEN WITH THE CURRENT PACKAGE WILL
BE SOME DRIER CONDITIONS OVER THE INNER CHANNELS TONIGHT AS IT
LOOKS LIKE THE FRONT HAS SLOWED SOME FROM LAST NIGHT. WITH THAT
SAID...RAIN WILL BEGIN TO DEVELOP OVER THE NORTHERN GULF COAST
AREAS EARLY THIS EVENING WITH THE MAJORITY OF THE REST OF THE
PANHANDLE ON THE DRY SIDE. WILL DROP THE POPS TO LIKELY OVER THE
COASTAL AREA OVER THE EASTERN GULF LATE TONIGHT AND CHANCES OVER
THE NORTH CENTRAL PANHANDLE BUT THROUGH FRIDAY RAIN WILL DEVELOP
ACROSS THE ENTIRE PANHANDLE. THE SOUTHERN HALF REMAIN UNDER THE
INFLUENCE OF THE UPPER RIDGE TO KEEP THEM DRY WITH A CHANCE OF
PRECIP IN THE MORNING THEN RAIN IN THE AFTERNOON.

.LONG RANGE...MODEL GUIDANCE FOR THE EXTENDED RANGE...SAT-THUR...
SHOWS MAJOR REVERSAL IN WEATHER PATTERN AFFECTING SE AK CAUSED BY
RETROGRESSION OF WESTERN NORTH AMERICA RIDGE AXIS FROM 130W TO 150W.
PREVAILING MOIST SW FLOW INTO SE AK WILL CHANGE TO COLDER NW FLOW
AROUND HI AMPLITUDE RIDGE EXTENDING OVER BEAUFORT SEA TO 80N. MAIN
MESSAGE BY END OF EXTENDED PERIOD WILL BE TEMPS COOLING TO SEASONAL
NORMALS...ABV FREEZING BY DAY AND BLO FREEZING BY NIGHT.

A SHARP SFC RIDGE BUILDS OVER FCST AREA SAT FOR DECRG WINDS AND
POSSIBLE FOG PROBLEMS. THE DRY WEATHER MAY BE SHORT LIVED. FORECASTS
WILL BE DIFFICULT EARLY NEXT WK DURING THE RIDGE RETROGRESSION AND
TRANSITION FROM SLY FLOW TO NLY FLOW. HIGH AMPLITUDE PROGRESSIVE SHORT
WAVES WILL BE MOVING NE THROUGH GULF UP THE W SIDE OF RIDGE AXIS AND
WEAKEN WHILE PUSHING INLAND UNDER THE MEAN UPPER RIDGE. SYSTEMS
INITIALLY ARE TAPPING TROPICAL MOISTURE AND PRODUCING OVER RUNNING
TYPE PRECIPITATION OVER AN INCREASINGLY COLDER SFC AIR MASS EDGING OUR
WAY FROM THE NW CANADA INTERIOR. WITH THE LONG WAVE UPR TROUGH
ANCHORED OVER THE BERING...THE SHORT WAVES WILL HAVE A TENDENCY TO
SPLIT AS THEY LIFT INTO THE NORTHERN GULF AND THE PORTION TRYING TO
MOVE INLAND UNDER THE UPPER RIDGE WILL WEAKEN. THESE SYSTEMS WILL ALSO
CAUSE OFFSHORE AS THEY APPROACH WHICH WILL ALSO AFFECT THE AMOUNT AND
TYPE OF PCPN OVER THE PANHANDLE.

FORECAST PROBLEMS WILL BE ASSOCIATED WITH HOW MUCH PRECIP WILL SPREAD
INLAND WITH SYSTEMS ON MON AND WED AND HOW MUCH OF THAT PRECIP WILL BE
IN THE FORM OF SNOW. ECMWF IS STRONGER AND WETTER THAN PREFERRED GFS
WITH FIRST WAVE ON MON. BOTH MODELS INDICATE SYSTEM ON WED WILL AFFECT
SOUTHERN PANHANDLE MORESO AS NW FLOW ALOFT BECOMES MORE DEVELOPED.
HOWEVER.. A SFC LOW CENTER MOVING SE CLOSE TO THE COAST...ENTRAINING
COLDER AIR INTO ITS N SIDE...IS FAVORABLE SNOW PATTERN N OF FREDERICK
SOUND. CURRENT FORECASTS CONVEY THE EXPECTED WEATHER WELL...NO MAJOR
ADJUSTMENTS IN EXTENDED FCST. TA

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...WND ADV...AKZ17
MARINE...GALE...PKZ52-51-43-42
         SCA...PKZ11-21-22-31>36