High Wind in Alaska, November 5, 2007

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST SUN NOV 4 2007

.SYNOPSIS...
.SHORT RANGE...THE MORNING SATELLITE IMAGERY IS REVEALING SOME
LARGE BREAKS IN AN OTHERWISE THIN BROKEN TO OVERCAST LAYER OVER
MUCH OF THE PANHANDLE. CLOUDS ARE ON THE INCREASE AS A BAROCLINIC
LEAF PUSHES INTO THE SOUTHERN PORTION OF THE PANHANDLE FROM THE
WEST AND SLOWLY PROPAGATES NORTH. THIS IN ADVANCE OF A DEVELOPING
GALE FORCE LOW THAT WILL AFFECT THE PANHANDLE TONIGHT THROUGH
TOMORROW.

PRIMARY FORECAST ISSUE WILL BE TIMING THE ONSET AND DETERMINING
THE EXTENT AND DURATION OF ADVISORY LEVEL WINDS. INITIAL
IMPRESSION IS THAT THE EXISTING START TIME FOR ZONE 27 IS STILL
GOING TO WORK OUT WITH ZONES 24...26...AND 28 STARTING SOON
THEREAFTER. GFS HAS NUDGED THE TRACK OF THE LOW SLIGHTLY WEST IN
THE LATEST MODEL RUN BUT NOT MADE SIGNIFICANT CHANGES TO CENTRAL
PRESSURE. UKMET...ON THE OTHER HAND...HAS SLOWED THIS SYSTEM DOWN
AND WEAKENED IT BY A FULL 4 MB  AS WELL AS NUDGE THE TRACK EAST
IN THE MOST RECENT MODEL RUN. END RESULT IS THAT THE CURRENT
UKMET AND GFS RUNS ARE VERY CLOSE TO EACH OTHER IN TERMS OF THE
SURFACE PRESSURE FOR THIS SYSTEM. GFS IS MAINTAINING A TIGHTER
PRESSURE GRADIENT ON THE NORTH SIDE OF THE SYSTEM AS IT COMES
ASHORE OVER THE CENTRAL COAST AND...CORRESPONDINGLY...GFS HAS THE
STRONGER SURFACE WIND FIELD OF THE 2 MODELS AND IS THE PREFERRED
SOLUTION FOR THE SHORT TERM FORECAST PERIOD. SOME CHANGES TO THE
DURATION OF THE WINDS ADVISORY EVENT ARE POSSIBLE GIVEN THE
LATEST MODEL RUN.

THE OTHER FORECAST ISSUE FOR THE SHORT TERM WILL BE THE NATURE OF
THE PRECIPITATION ASSOCIATED WITH THIS LOW. IN BRIEF...BELIEVE WE
WILL HAVE MIXED PRECIP AT THE START TONIGHT IN ZONES 27 AND 28
CHANGING TO RAIN BEFORE MONDAY MORNING. HYDER WILL LIKELY START
OUT AS ALL SNOW CHANGING TO RAIN AROUND NOON ON MONDAY. SNOW
CHANGING TO MIXED PRECIP BY MONDAY AFTERNOON FROM THE VICINITY OF
CROSS SOUND EAST TO JUNEAU AND SOUTH TO FREDERICK SOUND AND PORT
ALEXANDER. WHAT LITTLE PRECIP FALLS NORTH OF JUNEAU WILL MOST
LIKELY BE ALL SNOW.

.LONG RANGE...THE LOW MENTIONED IN THE SHORT TERM HEADS EAST INTO
BRITISH COLUMBIA EARLY MON EVENING AND WILL BE FOLLOWED BY A VERY
WEAK RIDGE FOR THE REMAINDER OF MON NIGHT. ANY SNOW/RAIN NORTH
AND RAIN SOUTH FROM THE LOW WILL END EARLY IN THE EVENING WITH
CLOUDS AND LOW POPS FOR THE REMAINDER OF THE NIGHT. WINDS WILL
BECOME LIGHT.

NOT MUCH CHANGE IN MODELS IN HANDLING THE LONG WAVE PATTERN
THROUGH THE WEEK AND INTO NEXT WEEKEND. AN BROAD UPPER LEVEL
LOW/TROUGH OVER THE SOUTHERN BERING/ALEUTIANS AND CENTRAL PACIFIC
WILL GRADUALLY SHIFT EAST INTO THE GULF AND EASTERN PACIFIC
TOWARD THE END OF THE WEEK INTO NEXT WEEKEND. THERE IS HOWEVER
LOTS OF DISCREPANCIES FROM RUN TO RUN IN HANDLING THE INDIVIDUAL
SYSTEMS THAT WILL MOVE NORTH OR NORTHEAST INTO THE GULF THROUGH
NEXT WEEKEND.

THE NEXT LOW IS TRACKING FURTHER WEST OVER THE SOUTHWEST GULF
INTO THE BERING SEA TUE THROUGH WED. THE OCCLUDED FRONT
ASSOCIATED WITH THIS LOW WILL BRING INCREASING WINDS (SMALL CRAFT
TO GALES) AND RAIN OVER THE OFFSHORE AND NORTHERN GULF COAST
REGION TUE AND TUE NIGHT...WHILE A WEAK LOW MOVING NORTHEAST
ACROSS THE QUEEN CHARLOTTES MAY CLIP THE FAR SOUTHERN PANHANDLE
WITH CLOUDS AND LIGHT RAIN AND BRING OFFSHORE FLOW AND POSSIBLE
CLEARING SKIES TO THE REMAINDER OF THE PANHANDLE (MAY KEEP MOSTLY
CLOUDY FOR NOW UNTIL CONFIDENCE IS HIGHER). THE OCCLUDED FRONT
WILL DISSIPATE AS IT MOVES INTO THE REMAINDER OF THE PANHANDLE
WED BRINGING CLOUDS...A LITTLE LIGHT RAIN (LIGHT SNOW
NORTHEAST)...AND NO SIGNIFICANT WINDS.

BEYOND WED...THE POTENTIAL IS THERE FOR A COUPLE OF STRONG STORMS
TO DEVELOP AND MOVE NORTH INTO THE GULF THROUGH THE WEEKEND BUT
DIFFICULT TO PINPOINT EXACT TRACK...INTENSITY...AND TIMING.
CHANCE TO LIKELY POPS FOR RAIN (RAIN AND SNOW FAR NORTHEAST) AND
LIMITING MARINE WINDS TO GALES IS REASONABLE AT THIS TIME.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...WIND ADVISORY AKZ023-026>028
MARINE...GALES PKZ041>043-035>036
         SMALL CRAFT PKZ021>022-031>034-051

FCF/TAR