Small Craft Advisory 534, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST FRI NOV 9 2007

.SYNOPSIS...

.SHORT RANGE...MODELS IN FAIRLY GOOD AGREEMENT THROUGH SATURDAY
AFTERNOON. WEAKENING WEATHER ASSOCIATED WITH SURFACE LOW OVER
EASTERN BRISTOL BAY EXTENDING SOUTH SOUTHEAST ACROSS THE WESTERN
AND CENTRAL GULF OF ALASKA. A STRONG JET STREAM OVER THE NORTH
CENTRAL PACIFIC AND SOUTHERN GULF OF ALASKA. THERE IS A
DEVELOPMENT OF A LOW EXPECTED OVER THE NORTHEAST PACIFIC THROUGH
THIS EVENING THAT SHOULD MOVE NORTHWARD AND ACROSS THE SOUTHERN
PANHANDLE TONIGHT. IT SHOULD BRING A BRIEF PERIOD OF WINDS COMING
IN WITH THIS LOW. ALONG WITH A BAND OF HEAVIER PRECIPITATION. AS
THE LOW MOVES TO NORTH TO THE SOUTHERN PANHANDLE THE WEAKENING
FRONT WILL SLOWLY LIFT TO THE NORTHEAST AND EXPECTED TO PUSH
ONSHORE SATURDAY.

IN THE NEAR TERM THE GUSTY OUTFLOW WINDS THROUGH INTERIOR PASSES
OVER THE NORTHERN PANHANDLE SHOULD BE DIMINISHING BY AFTERNOON
AND THE PRESENT WIND ADVISORIES MAY BE DROPPED EARLIER THAN
INITIALLY EXPECTED.  MARINE FORECASTS UPDATED TO LOWER THE WINDS
THAT HAVE DIMINISHED ALREADY REMOVING THE GALE WARNING FROM THE
NORTHERN LYNN CANAL REGION.

.LONG RANGE...THE GFS HAS A TRACK OF A LOW IN THE CENTRAL GULF
WITH A CENTRAL PRESSURE IN THE 940S 12Z THU...AND WHILE THE PATH
OF THE LOW SEEMS USEFUL THE LOW SHOULD EITHER DEEPEN SLOWER OR MOVE ALONG
THE TRACK AT A SLOWER PACE.  PRIOR TO WED THE MODEL DIFFERENCES AR SMALLER
AND A CONSENSUS IS USED.

LOW TRACK TOWARD SRN PNHDL SUN NIGHT IS BETWEEN THE GFS AND NAM SOLUTIONS.
LONG RANGE MODEL SPREAD BCMG LARGER BGNG TUE...AND
00Z THU THE PRESSURE DIFFERENCES BETWEEN THE ECMWF AND THE GFS
ARE AS HIGH AS 41 MB NEAR THE LOW THAT THE GFS HAS TRACKING
NE INTO THE EAST CENTRAL GULF OF ALASKA.  THE GFS SOLUTION DOES
HAVE SOME MERIT BUT IS EITHER TOO FAST OR TOO STRONG WITH THE
LOW...BUT THE PATH OF THE LOW MAY BE GOOD.

SEVERAL COORDINATIONS BETWEEN ANCHORAGE EAST DESK RESULTED IN
A GAME PLAN THAT USES THE GFS WITH TIME OFFSETS AND OTHER
ADJUSTMENTS.  BY 00Z THU THE LOW TRACK HAS BEEN SLOWED DOWN
TO THE 12Z WED GFS POSN AND THE 12H SLOWDOWN IS USED THRFTR
WITH A PRESSURE WEAKENING OF THE LOW OF ABOUT 12 MB THROUGH THU.
NOTE THE GFS AND ECMWF SOLUTIONS MERGE WELL BY 12Z FRI.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...WIND ADVISORY AKZ018-019-025
MARINE...SMALL CRAFT PKZ011-012-013-31-041>043-051-052

BMB JT