Gale Warning 87, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1100 AM AST SAT FEB 16 2008

.SYNOPSIS...
.SHORT RANGE...A 981 MB GALE FORCE LOW SOUTH OF KODIAK THIS
MORNING WILL CONTINUE TRACKING NORTH TOWARDS COOK INLET.
SCATTEROMETER DATA INDICATES THAT THIS SYSTEM HAS DEVELOPED INTO
A MARGINAL STORM FORCE LOW AS EXPECTED WITH A FEW 50 KT WIND
BARBS SHOWING UP IN THE SOUTHEAST SECTOR.

BIGGEST CONCERN TODAY IS PRECIP TYPE. WITH THE HIGH QPF VALUES
ALONG THE COAST NORTH OF CAPE EDGECUMBE...A LOT IS RIDING ON RAIN
VS. SNOW. CURRENT THINKING IS RAIN DURING THE HEAVIEST
PRECIPITATION BUT IF THIS TIMING IS OFF...ZONES 20 THROUGH 22
COULD EASILY SEE ADVISORY LEVEL SNOWFALL OR HIGHER. LATEST MODEL
DATA DOES SHIFT THE QPF MAXIMA NORTH ALONG THE COAST TOWARDS
YAKUTAT WHERE THERE IS ALREADY A HEAVY SNOW WARNING IN PLACE.

SNOW HAS BEGUN FALLING IN YAKUTAT WITH CEILINGS AND VISIBILITY
DROPPING VERY ABRUPTLY. CURRENTLY SEEING EASTERLY WINDS THERE
WHICH WILL TEND TO MAINTAIN THE SNOW. AT THIS POINT...STILL
EXPECTING HEAVY SNOW THROUGH AROUND MIDNIGHT. ELSEWHERE...PRECIP
HAS REACHED THE OUTER COAST AS FAR SOUTH AS AT LEAST CAPE SPENCER
WHERE THE WEB CAMERA IS REVEALING A RAIN SNOW MIX RIGHT NOW. HAVE
HAD SOME PERIODS OF LIGHT SNOW ALSO IN JUNEAU ALREADY AS WELL.
SATELLITE IMAGERY IS SUGGESTING THAT THE SNOW SHOULD BEGIN IN THE
HAINES AND SKAGWAY AREAS WITHIN THE NEXT COUPLE HOURS...SO HEAVY
SNOW WARNINGS IN THOSE ZONES LOOK TO BE ON TRACK AS WELL.

AS FAR AS WINDS ARE CONCERNED...LATEST MODEL DATA SUGGESTS THAT
WINDS ASSOCIATED WITH THIS FRONT AND THE ASSOCIATED LOW MAY NOT
BE AS STRONG AS ORIGINALLY EXPECTED. AT THIS POINT...INTENDING TO
LEAVE WIND ADVISORIES IN PLACE BUT DO BELIEVE THAT ADVISORY
CRITERIA WILL BE MET ONLY ALONG THE OUTER COAST OF THE AFFECTED
ZONES.

THE WEATHER FRONT PRODUCING THESE ADVISORIES AND WARNINGS LOOKS
LIKE IT WILL MAKE ITS FARTHEST SOUTHERLY PENETRATION INTO THE
PANHANDLE LATE TONIGHT. IT IS HAVING TO WORK ITS WAY OVER A
SIGNIFICANT SURFACE RIDGE AND SO THERE IS NOT A LOT OF A WARM
FRONTAL SIGNATURE LEFT AS IT MAKES LANDFALL. WILL BE BACKING OFF
ON THE POP FOR THE SOUTHERN ZONES FOR TONIGHT AND SUNDAY AS A
RESULT WITH PRECIP LIKELY AS FAR SOUTH AS SUMNER STRAIT EAST TO
WRANGELL. ONLY GOING FOR A CHANCE FOR THE SOUTHERN ZONES. FCF

.LONG RANGE...THE MODELS AND THE ENSEMBLES ARE IN FAIR AGREEMENT
THIS MORNING THROUGH THE MID RANGE BUT THEN THEY BEGIN TO DIVERGE
IN SOLUTIONS LATE WEEK INTO NEXT WEEKEND. WITH THAT SAID WILL NOT
MAKE ANY BIG CHANGES THROUGH EARLY THIS WEEK JUST MINOR CHANGES
USING THE 12Z GFS. THERE IS LOW FORECASTER CONFIDENCE FROM WED
INTO NEXT WEEKEND WITH LARGE SCALE UPPER LEVEL FLOW DIFFERENCES.

WITH THE VERY STRONG WESTERLY JET ALONG THE NORTHERN PACIFIC AND
A THE PERSISTENT UPPER LEVEL RIDGE OVER THE WESTERN NOAM...THE
GULF OF AK WILL REMAIN TO SEE LOW PRESSURE DEVELOPMENT THROUGH
THE WEEK. THE UPPER LEVEL FLOW OVER SE AK WILL REMAIN OUT OF THE
SW TO KEEP TEMPS ON THE MILD SIDE THROUGH MOST OF THE WEEK. SO
MOST OF THE PRECIP WILL FALL IN THE LIQUID FORM. THERE WILL NOT
BE A COOL DOWN UNTIL LATE WEEK INTO NEXT WEEKEND.

RAIN WILL CONTINUE OVER THE NORTHERN HALF OF THE PANHANDLE
THROUGH SUN NIGHT...THERE WILL BE JUST A CHANCE OF PREICP OVER
THE SOUTHERN AREAS BUT AS THE UPPER RIDGE SLIDES TO THE EAST THE
THREAT OF RAIN WILL INCREASE THROUGH THE NIGHT. A LOW WILL
DEVELOP ALONG THE BAROCLNIC ZONE AS A UPPER LEVEL SHORTWAVE LIFTS
OUT OF THE NE PACIFIC AND INTO THE EASTERN GULF MON MORNING.
WINDS WILL INCREASE OVER THE SOUTHERN AREAS LATE SUN NIGHT INTO
MON MORNING WITH POSSIBLE WIND ADV NEEDED.

THE LOW WILL WEAKEN TO A TROF OVER THE NORTHERN GULF THROUGH MON
AS THE SHORTWAVE LIFTS INTO THE YUKON. THERE WILL A SHORT BREAK
IN THE PRECIP AS A UPPER RIDGE BUILDS OVER BC WITH SE FLOW ALOFT
OVER THE AREA. ANOTHER STRONG 965MB LOW WILL DEVELOP IN THE
PACIFIC AND TRACK ACROSS THE SOUTH CENTRAL GULF TUE AND INTO THE
WESTERN BY THAT NIGHT. THIS WILL BRING IN SOME MORE RAIN FOR THE
PANHANDLE BUT THE AMOUNTS WILL NOT BE THAT MUCH. THINK THE
STRONGEST WINDS WILL REMAIN OVER THE COASTAL WATERS AND NOT MAKE
IT INTO THE INNER CHANNELS.

ANOTHER LOW WILL DUMBBELL AROUND THE LOW IN THE WESTERN GULF AND
LIFT INTO THE THE CENTRAL GULF BY THURS AFTERNOON AND LIFT A
FRONT OVER THE PANHANDLE THAT NIGHT. A SURFACE LOW WILL REMAIN IN
THE GULF INTO THE WEEKEND AS THE PARENT UPPER LOW OVER THE GULF
REMAINS IN PLACE. THERE WILL BE SOME COLDER AIR WRAPPING AROUND
THIS UPPER LOW TO ADVECT COLDER AIR OVER THE AREA FRIDAY NIGHT
INTO SAT.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...HVY SNOW WRNG: AKZ017>018
         WIND ADVSRY: AKZ017-022>023-027

MARINE...STORM: PKZ052
         GALE: PKZ041>043-051-033-036
         SMCR: PKZ011-021>022-031>032-034>035