Gale Warning 369, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
1200 PM AST FRI DEC 21 2007

.SYNOPSIS...
.SHORT RANGE...LATEST SATELLITE IMAGERY DEPICTS THREE SEPARATE
STRONG LOWS LOCATED IN THE GULF AND NORTHERN PACIFIC.  THE FIRST
OF THESE LOWS IS A 975 MB STORM MOVING NORTHWARD INTO PRINCE
WILLIAM SOUND.  AN OCCLUSION EXTENDS SOUTHEASTWARD TOWARDS THE
PANHANDLE THEN SOUTHWESTWARD TO A SECOND LOW LOCATED NEAR 48N
140W.  THIS SECOND LOW IS RAPIDLY DEEPENING AS IT MOVES
NORTHEASTWARD TOWARDS DIXON ENTRANCE.  THE THIRD LOW IS SLIDING
EASTWARD ALONG THE ALASKAN PENINSULA.

GALE FORCE WINDS CONTINUE ACROSS THE GULF MARINE WATERS AS WELL
AS LINCOLN ROCK AND CAPE DECISION.  ADVISORY LEVEL WINDS ARE ALSO
BEING REPORTED AT SITKA...KETCHIKAN/METLAKATLA...AND YAKUTAT.
MOST LOCATIONS HAVE WARMED ENOUGH TO CHANGE OVER TO RAIN OR MIX
WITH RAIN.  TEMPERATURES REMAIN COLD ENOUGH TO SUPPORT SNOW IN
HYDER...HAINES AND SKAGWAY.  HAINES CONTINUES UNDER HEAVY
SNOWFALL WITH VISIBILITY OF A QUARTER-MILE.  SNOW HIGHLIGHTS HAVE
BEEN DROPPED FOR ALL BUT THE AFOREMENTIONED LOCATIONS.

AS THE OCCLUDED FRONT MOVES INLAND THROUGH THE DAY
TODAY...ADVISORY LEVEL WINDS WILL DIMINISH ALONG THE NORTHERN
COAST BY LATE THIS AFTERNOON.  THE SOUTHERN PANHANDLE MAY SEE A
BRIEF REPRIEVE FROM WINDS THIS EVENING BEFORE THEY PICK BACK UP
TONIGHT.  THE SECOND LOW...DIRECTED TOWARD DIXON ENTRANCE DEEPENS
TO AROUND 973 MB OVERNIGHT.  MODELS DEPICT AT LEAST ADVISORY
LEVEL WINDS WITH WARNING GUSTS PROBABLE FOR ZONES 27 AND 28.
WILL EXPLORE THE POTENTIAL FOR STORM FORCE SUSTAINED WINDS IN
CLARENCE AND MARINE 41.

PRECIPITATION TYPE WILL AGAIN BE TRICKY THROUGH TOMORROW.
OVERNIGHT...EXPECT LOWS TO FALL NEAR OR SLIGHTLY BELOW FREEZING
IN THE NORTH...THEN WARM SLIGHTLY DURING THE DAY SATURDAY.  WILL
GO WITH A MIX OR A MIX BECOMING SNOW OVERNIGHT.  LYNN CANAL AREA
WILL CONTINUE TO STRUGGLE TO WARM. THE POTENTIAL FOR A
DEFORMATION BAND TO DEVELOP NORTHWEST OF THE SECOND LOW CENTER
WILL ALSO BE A CONCERN. THEREFORE WILL KEEP SNOW IN THE FORECAST.
MUCH OF THE SOUTH SHOULD STICK TO RAIN WHILE INLAND PORTLAND
CANAL/HYDER WILL SEE SNOW.

.LONG RANGE...
ACTIVE WEATHER PATTERN WILL CONTINUE TO AFFECT SE AK THROUGH NEXT
WEEK. COLD LONG WAVE TROUGH EXTENDS S FROM N POLE JUST EAST OF
DATELINE. LONG WAVE RIDGE JUST OFF CONUS W COAST. RESULT IS
STRONG AND WET STORM TRACK THROUGH GULF AK. SEVERAL VERY DEEP SFC
LOWS ARE FCST TO DEVELOP FROM WARM WAVES AROUND 40N AND BARREL
TOWARD SE AK WITH HIGH WINDS...HEAVY SEAS...AND PLENTY OF PRECIP.
SYSTEMS ARE TAPPING INTO JUICY TROPICAL CONVERGENCE ZONE.
LOCATION OF RAIN-SNOW LINES WILL BE ANOTHER TRICKY PROBLEM IN THE
EXTENDED RANGE.

FAVORING GFS MODEL AGAIN TODAY BASED ON ITS ACCURATE
INITIALIZATION OF ALL UPSTREAM SYSTEMS. TODAYS RUN IS A BIT
FASTER ON DETAILS THROUGH TUE...AS IS ECMWF AND SREF...SO I WILL
NUDGE GRID FORECASTS SLIGHTLY EASTWARD. PANHANDLE WILL BE IN
BETWEEN FRONTS SAT NIGHT BUT THINGS CHANGE QUICKLY SUN. LOW
CENTER DEVELOPING TODAY AT 38N 177W IS FCST TO TRAVEL 40KTS TO BE
JUST OFF DIXON ENTRANCE SUNDAY MORNING WHILE DEEPENING TO 960 MB.
GUIDANCE SUGGESTS 1-2 INCHES OF LIQUID PRECIP POSSIBLE WITH THIS
SYSTEM...GREATEST OVER SRN PANHANDLE... ALONG WITH GALE TO STORM
FORCE WINDS ALONG S COAST AND SRN CLARENCE STR. APPEARS TO BE A
WRM CORE SYSTEM SO FRZG LEVELS WILL BUMP UP SOME AND MELT LOW
LEVELS SNOW...AGAIN MAINLY S HLF PANHANDLE...WHICH MAY AGGRIVATE
HYDRO SITUATION SUN INTO MON.

ALL GUIDANCE SHOWS ANOTHER LOW CENTER AIMING TOWARD SE AK MON
NIGHT AND EARLY TUE. THIS ONE IS SHOWING BROAD AREA OF STORM
FORCE SE WIND AHEAD OF FRONT. HEAVY PRECIP POTENTIAL FOR IS FOR
NORTHERN ZONES INSTEAD...ESP YAKUTAT. MOIST ONSHORE FLOW THROUGH
MID WEEK KEEP POPS VERY HIGH. ANOTHER STRONG STORM MOVES WEST
ACROSS THE GULF THU AND IS CURRENTLY PREDICTED TO MAKE LANDFALL
OVER SRN QN CHARLOTTE SOUND WHICH MAY ACTUALLY HELP REVERSE THE
FLOW ALF TO EASTERLY AND HELP DRY OUT PANHANDLE BRIEFLY BUT NOT
BANKING ON IT YET.  TA

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...HVY SNOW WARN...ZONE 19
         SNOW ADVY...ZONES 18-29
         WIND ADVY...ZONES 17-22-23-26-27-28-29
         HI WIND WARN...ZONES 27-28 TONIGHT

MARINE...STORM WARN...ZONES 51-52
         GALE WARN...ZONES 33-35-36-41-42-43-53-310
         SMCR...ELSEWHERE