Gale Warning 326, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST MON NOV 19 2007

.SYNOPSIS...
.SHORT RANGE...A 1024 MB CENTER OF HIGH PRESSURE IS ANCHORED
OVER WESTERN BRITISH COLUMBIA WITH A 974 MB LOW ENTERING THE
GULF OF ALASKA THIS MORNING. THE FIRST EFFECTS OF THE ADVANCING
LOW PRESSURE CENTER IN THE GULF ARE BEING FELT OVER THE NORTHERN
PANHANDLE WITH THE ONSHORE FLOW. HOWEVER, WITH THE ADVANCING
UPPER LEVEL RIDGE ALOFT IT IS LIMITING THE PRECIPITATION TO JUST
A FEW RAIN AND SNOW SHOWERS NEAR THE YAKUTAT AREA. THE ADVANCING
UPPER LEVEL RIDGE WILL ALLOW FOR MOSTLY CLOUDY TO PARTLY CLOUDY
SKIES TODAY OVER THE SOUTHERN PANHANDLE ONCE THE AREAS OF FOG IN
THE INNER CHANNELS LIFT BY THE EARLY AFTERNOON. WINDS OVER THE
PANHANDLE ARE GENERALLY LIGHT THIS MORNING WITH THE RELATIVELY
WEAK PRESSURE GRADIENT. THE LONE EXCEPTION BEING THE SKAGWAY
AREA WHERE A STRONG SOUTHERLY GRADIENT ALONG LYNN CANAL IS
ALLOWING FOR BREEZY CONDITIONS.

THE UPPER LEVEL LOW AND ITS ASSOCIATED SURFACE WAVE WILL
CONTINUE TO PUSH NORTHWARD THIS EVENING AND BY MID AFTERNOON
TUESDAY WILL BE JUST SOUTHEAST OF KODIAK INLAND. THE UPPER LEVEL
RIDGE AHEAD OF THE LOW NEAR KODIAK WILL CONTINUE TO DOMINATE THE
WEATHER OVER THE SOUTHERN PANHANDLE INTO MIDDAY TUESDAY. THIS
WILL ALLOW FOR PARTLY CLOUDY TO MOSTLY CLOUDY SKIES WITH FOG
FORMING ACROSS THE INNER CHANNELS OVERNIGHT. ONSHORE FLOW WILL
CONTINUE ACROSS THE NORTHERN PANHANDLE WITH PRECIPITATION BEING
LIMITED TO MAINLY THE YAKUTAT AREA THROUGH TUESDAY MORNING. RAIN
SHOWERS WILL BE MIXED WITH SNOW AT TIMES OVERNIGHT NEAR YAKUTAT.
WITH THE ADVANCING WARM AIR ALOFT AHEAD OF THE NEXT SURFACE
FRONT THE SNOW ACCUMULATION NEAR YAKUTAT WILL LIMITED THROUGH
TUESDAY.

USED THE GFS MODEL IN THIS PACKAGE BEING MOST CONSISTENT BETWEEN
THE PAST FEW RUNS WITH THE TIMING AND STRENGTH OF THE UPPER
LEVEL LOW AND ITS SURFACE FEATURES. THE CHIEF CONCERN FOR THIS
PACKAGE IS THE PRESSURE GRADIENT INCREASE BETWEEN THE BUILDING
SURFACE HIGH OVER BRITISH COLUMBIA AND THE LOW PRESSURE CENTER
MOVING NORTHWARD TOWARD KODIAK ISLAND BY MIDDAY TUESDAY. AS THE
SURFACE GRADIENT INCREASES INTO TUESDAY AN AREA OF GALES WILL
FORM OFFSHORE AND IN THE NORTHERN GULF. BARRIER FLOW WILL ALSO
ENHANCE THE LOCAL PRESSURE GRADIENT NEAR CAPE SUCKLING. WITH THE
INCREASING SOUTHEASTERLY GRADIENT GUSTS ABOVE WIND ADVISORY
CRITERIA ARE EXPECTED NORTH AND WEST OF CROSS SOUND TUESDAY. PSS

.LONG RANGE...THERE IS GOOD MODEL AGREEMENT THROUGH THURSDAY
MORNING WITH THE ENSEMBLES MEMBERS ALONG WITH OTHER GLOBAL
MODELS. SPREADS WITH ENSEMBLES MEMBERS AND OPERATIONAL MODELS
INCREASE DRASTICALLY LATE THIS WEEK INTO THE WEEKEND SO WITH THAT
SAID WILL NOT CHANGE THE CURRENT FORECAST FROM THURSDAY AFTERNOON
THROUGH MONDAY. IT LOOKS LIKE THE 12ZGFS40 AND THE 12ZUKMET
INITIALIZED WELL WITH THE LOW AND ASSOCIATED WEATHER FRONT MOVING
INTO THE WESTERN GULF...SO WILL BLEND THOSE TWO MODELS THROUGH
THURSDAY AFTERNOON INTO THE GRIDS.

AT THE UPPER LEVELS...THE UPPER RIDGE OVER BC WILL CONTINUE TO
DRIFT EAST AS A LOW OVER THE WESTERN GULF LIFTS NW INTO THE
BRISTOL BAY AREA THROUGH TUE NIGHT. A TROF OVER THE CENTRAL GULF
TUE AFTERNOON WILL LIFT OVER THE PANHANDLE THROUGH THE NIGHT AND
BE OVER BC BY WED MORNING. ANOTHER RIDGE WILL BUILD OVER THE
THROUGH WED NIGHT WITH THE AXIS OVER SE AK. THIS RIDGE WILL PUSH
TO THE EAST THROUGH THURSDAY AS ANOTHER LOW LIFTS N INTO THE
WESTERN GULF AND PUSH A TROF OVER THE GULF AND THE PANHANDLE
THROUGH FRIDAY.

AT THE SURFACE...A AREA OF HIGH PRESSURE OVER CENTRAL/SOUTHERN BC
WILL CONTINUE TO BUILD THROUGH WED NIGHT. A SURFACE LOW OVER THE
WESTERN GULF WILL CONTINUE TO WEAKEN THROUGH TUE NIGHT AS IT
LIFTS NW INTO BRISTOL BAY. THE ASSOCIATED FRONT WILL PUSH OVER
THE NORTHERN GULF AND INLAND THROUGH TUE NIGHT. THERE WILL BE
SIGNIFICANT WINDS OVER THE NORTHERN AND EASTERN GULF WITH 40 TO
45KT OF WINDS WITH THEN POTENTIAL OF HIGHER GUSTS WEST OF ICY BAY
THROUGH TUE EVENING. THERE WILL ALSO BE WIND ADV LEVEL WINDS
ALONG THE COASTAL LAND AREAS FROM PASI NORTHWARD CONTINUING INTO
TUE EVENING BUT AS THE FRONT GOES ALOFT THE STRONG GUSTS WILL
DIMINISH OVER NIGHT. AS FOR PRECIP...THINK MOST WILL FALL IN THE
LIQUID FORM AS THERE WILL BE CONTINUED WARMING WITH SOUTHERLY
FLOW A LFOT. RAIN WILL CONTINUE IN PAYA WILL PERSIST THROUGH WED
AFTERNOON WITH STRONG ONSHORE FLOW AT MOST LEVELS. THE INSIDE
CHANNELS MAY BE TRICKY IN PLACES AS WITH THE HIGH IN BC THERE
WILL BE A EASTERLY GRADIENT THAT MAY KEEP SOME COLD AIR IN WIND
SHELTERED AREAS. FOR THE MOST PART THE PTYPE WILL BE RAIN AS IT
SHOULD DEVELOP ACROSS THE ENTIRE THROUGH TUE NIGHT AS THE UPPER
TROF MOVES OVER THE AREA. THE PRECIP WILL CONTINUE INTO WED AS
THERE WILL BE ONSHORE FLOW AT ALL LEVELS. THE RAIN WILL BEGIN TO
TAPPER OFF THROUGH WED NIGHT AND SHOULD BE MAINLY DRY ON THURSDAY
OVER MOST OF THE PANHANDLE AS THE UPPER RIDGE BUILDS OVER THE
AREA AND AGAIN THERE WILL BE A SURFACE OFFSHORE FLOW WITH THE
HIGH BEGINNING TO WEAKEN.

THERE IS LOW CONFIDENCE FROM THURSDAY AFTERNOON THROUGH THE
WEEKEND AS THE UPPER LEVEL PATTERN HAS BEEN CHANGING FROM RUN TO
RUN IN THE MODELS. WITH THAT SAID...A SURFACE TROF WILL DRIFT
ACROSS THE GULF THROUGH THURSDAY AND WEAKEN AS IT MOVES OVER THE
PANHANDLE THURSDAY NIGHT/FRIDAY. THIS TROF WILL AGAIN INCREASE
THE WINDS OVER THE GULF TO MAX SMALL CRAFT/MIN GALES. THIS SYSTEM
WILL BE A WARM ONE SO FOR THE MOST PART THE PRECIP WILL BE
LIQUID.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...
MARINE...SMCR...PKZ011>013-021-022-041>043-051-052