Gale Warning 229, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
630 AM ADT FRI SEP 21 2007

.SYNOPSIS...
.SHORT RANGE...WEAK SFC LOW OVER NE GULF WILL DISSIPATE BY THIS
EVENING. MID-LEVEL SHORTWAVE TROF WILL DROP SE THRU THE AREA
TODAY...AS RIDGING BUILDS OVER THE ERN GULF THRU TONIGHT. LOW
PRESSURE WILL MOVE NE TO THE FAR WRN GULF TONIGHT...WITH A WARM
FRONT EXTENDING FROM TRIPLE POINT OVER THE CENTRAL GULF INTO THE
FAR SE GULF.

MAIN FORECAST CONCERN FOR TODAY WILL BE HOW MUCH OF AN IMPACT THE
SHORTWAVE MOVING THRU THE AREA WILL HAVE. MID-LEVEL CLOUDS FROM
IT NOW ENTERING NRN SE AK...AND THESE SHOULD MOVE SE THRU MAINLY
THE ERN INNER CHANNELS TODAY. PLENTY OF LOW LEVEL MOISTURE OVER
THE AREA WITH LOTS OF LOWER SC AROUND...AND AS SHORTWAVE MOVES
THRU...THINK THERE MAY BE SPOTTY SHOWERS. THESE SHOWERS SHOULD
DIMINISH OVER THE N THIS AFTERNOON BEHIND THE SHORTWAVE...WITH
SOME DRIER LOW LEVEL AIR MOVING IN. AM GOING WITH LOW-MID RANGE
CHANCE POPS FOR MOST OF THE AREA TO HANDLE THIS SYSTEM...EXCEPT
ONLY GOING SLIGHT CHANCE FAR N PART. BECAUSE MODELS KEEP A WEAK
ONSHORE FLOW GOING AROUND 850 MB LEVEL THRU THE DAY...AM KEEPING
SKIES OVER THE LAND AREAS AT LEAST MOSTLY CLOUDY.

FOR TONIGHT...AS RIDGE MOVES IN...FLOW WILL BACK AROUND TO SW AND
THIS SHOULD INCREASE LOWER CLOUDS AGAIN. LOW LEVELS WILL BE
WEAKLY UNSTABLE SO EXPECT A FEW SHOWERS TO REMAIN OVER THE
AREA...WITH SOME INCREASE IN THE SHOWERS LATER TONIGHT AS A WEAK
LOWER LEVEL VORT TROF MOVES NE ACROSS THE AREA. THINK THE
STEADIER RAIN AND STRONGER WINDS WITH THE APPROACHING FRONT WILL
REMAIN OVER THE GULF THRU LATE TONIGHT...WITH AT LEAST SCA LEVEL
WINDS LIKELY BY LATE TONIGHT OVER THE OFFSHORE WATERS AND
N-CENTRAL GULF COASTAL WATERS.

OTHERWISE...WILL KEEP SCA SEAS GOING OVER THE GULF WITH 8-13 FT
SEAS BEING REPORTED BY THE BUOYS...AND AKWAVE KEEPS THEM MOSTLY
ABOVE 8 FT THRU TONIGHT. THE FAR N GULF MAY SEE A PERIOD OF BELOW
SCA SEAS THIS AFTERNOON AND EVENING BEFORE THE STRONGER WINDS
ARRIVE AND KICK UP HIGHER SEAS AGAIN TOWARD DAYBREAK. RWT

.LONG RANGE...SEVERAL WEAK UPPER LEVEL SHORT WAVES MOVE OVER THE
PANHANDLE ON MONDAY...TUESDAY...AND THURSDAY MORNING FOLLOWED BY
A LARGE LONG WAVE TROUGH SOUTHEAST OF AN UPPER LOW CENTERED OVER
THE NORTHERN GULF LATE ON 01 OCT. THROUGHOUT THE LONG RANGE
FORECAST PERIOD...NAM IS MAINTAINING THE HIGHEST AMPLITUDE IN THE
UPPER LEVEL FEATURES BUT IS SLIGHTLY SLOWER THAN GFS FROM 24/12Z
THROUGH THE END OF THE NAM RUN. UKMET IS THE SLOWEST IN THE UPPER
LEVELS  FROM 24/12Z ON AND THE MOST ZONAL...SOUNDS SUSPICIOUS.
ENSEMBLE SPREAD NOT TOO BAD WITH THE GREATEST OCCURRING SUNDAY
NIGHT INTO MONDAY SOUTH OF THE PANHANDLE WEST OF THE DIXON
ENTRANCE. DIFFERENCES MOSTLY TO DO WITH THE STRENGTH OF THE UPPER
TROUGH RATHER THAN THE POSITIONING OF THE TROUGH-RIDGE PAIR.
ENSEMBLE SPREAD INCREASES BOTH IN AMPLITUDE AND SPEED OVER THE
PANHANDLE BY 27/00Z. MAXIMUM SPREAD OVER THE SOUTHERN HALF OF THE
PANHANDLE BY 27/06Z AND AGAIN 28/18Z.

AT THE SURFACE...QUITE A SPREAD OF SOLUTIONS STILL BEING OFFERED
BY THE VARIOUS MODELS WITH REGARD TO THE SYSTEM DEVELOPING SOUTH
OF THE PENINSULA AT THIS TIME BUT NOT AS PRONOUNCED AS EARLIER.
CENTRAL PRESSURES ALL WITHIN 4MB AND LOCATION SPREAD IS DOWN TO
180NM. NAM FARTHEST SOUTH AND GFS IS FARTHEST EAST WITH UKMET TO
THE NORTH AND WEST. HI RES ECMWF IS STAMPING A DOUBLE LOW WITH
THE SOUTHERN LOW ON TOP OF THE NAM LOW. NUDGED EXISTING GRIDS TO
CURRENT GFS40 60 PERCENT THROUGH SUNDAY AND 50 PERCENT
THEREAFTER.

A WET PATTERN IN STORE WITH SOME RELIEF FOR THE OUTER COAST
TUESDAY AFTERNOON AND EVENING AND MOST LOCATIONS ON THURSDAY. BUT
ANOTHER WELL ORGANIZED FRONT LOOKS LIKE IT WILL ARRIVE ALONG THE
PANHANDLE BY FRIDAY AFTERNOON. TOO SOON TO SAY HOW FAST THIS
FRONT WILL MOVE THROUGH THE AREA SO CANNOT SAY WITH CONFIDENCE
THAT NEXT WEEKEND WILL BE DRY. CURRENTLY CALLING FOR CHANCE OR
BETTER.

GALE FORCE WINDS EXPECTED IN THE COASTAL MARINE ZONES BEGINNING
THIS SUNDAY MORNING AND SPREADING SOUTH TO THE DIXON ENTRANCE
THROUGH THE DAY AS THE LOW COMES ASHORE VICINITY YAKUTAT SUNDAY
NIGHT. INNER CHANNELS WILL SEE PERIODS OF STRONG SMALL CRAFT
CONDITIONS ON SUNDAY WITH CONDITIONS MODERATING ON MONDAY.
ANOTHER ROUND OF SMALL CRAFT WINDS ON THE CENTRAL COAST AND
CENTRAL AND SOUTHERN INNER CHANNELS AGAIN ON TUESDAY.
FINALLY...THE FRONT NEXT FRIDAY WILL BRING EXTENSIVE STRONG SMALL
CRAFT CONDITIONS ALONG THE OUTER COAST WITH GALES FROM CAPE
DECISION TO CAPE FAIRWEATHER POSSIBLE.

NO SNOW IN THE FORECAST YET BUT SNOW LEVELS ARE BEGINNING TO COME
DOWN. FCF

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...NONE

MARINE...SCA...PKZ022-041>043-051-052