Gale Warning 50, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
630 AM AST WED JAN 17 2007

.SYNOPSIS...
.SHORT RANGE...FIRST TO MENTION IS THAT WFO JUNEAU IS EXPECTING
TO UNDERGO A SOFTWARE UPGRADE (TO OB7.1) TODAY AND THAT ANCHORAGE
IS PLANNING ON BACKING US UP AND THUS WILL COVER OUR FORECAST
AREA THROUGH THIS AFTERNOON...BARING ANY PROBLEMS WITH BACK UP
PROCEDURES.

WEATHER FRONT MOVING ACROSS THE EASTERN GULF AND ONSHORE
SOUTHEAST ALASKA WEDNESDAY BRINGING GALE FORCE WINDS TO THE
COASTAL WATERS TODAY WHILE SNOW AND SOME AREAS OF RAIN FALL
ACROSS THE PANHANDLE. EXPECT THAT SOUTH CENTRAL INNER CHANNELS
WILL ACCUMULATE AROUND SNOW ADVISORY AMOUNTS BETWEEN MIDDAY AND
MIDNIGHT AS THE FROM MOVES THROUGH BEFORE THOSE AREAS WARM UP
ENOUGH TO GO MAINLY RAIN.  OVER THE REST OF THE PANHANDLE EXPECT
GENERALLY SNOW WITH SOME PERIODS FOR RAIN THIS AFTERNOON FOR THE
AREAS CLOSER TO THE OUTER COAST.

A SECOND DEVELOPING WAVE TRAILING THIS FIRST FRONT BAND IS JUST
STARTING TO CROSS NORTH OF 50N INTO THE GULF OF ALASKA AN IS THE
SYSTEM I THAT SHOULD BRING THE BETTER SNOW AMOUNTS TO THE
NORTHERN PANHANDLE REGIONS. BELIEVE THAT THERE WILL BE SOME MINOR
COOLING AHEAD OF THIS FRONTAL BAND THAT GETS PULLED IN FROM
CANADA...BUT THE BEST AREAS FOR THE SNOW ARE GOING TO BE NORTHERN
LYNN CANAL AND NORTHERN GLACIER BAY.  THE AMOUNT OF COLD AIR IS A
LITTLE QUESTIONABLE SO HAVE JUST OPTED TO GO WITH WINTER STORM
WATCH FOR THOSE AREAS.

HAVE PREDOMINATELY USED THE GFS AS THE BASIS FOR THE FORECAST
PACKAGE.  FELT THAT IT OF THE US MODELS HAD THE BEST HANDLE ON
THE FIRST WEATHER FEATURE TO IMPACT SOUTHEAST ALASKA.  EXPECT TO
SEE WINDS CLIMB UP TO GALE FORCE AGAIN FOR THURSDAY FOR THE
EASTERN HALF OF THE GULF.

.LONG RANGE...ANOMALOUS 500 MB HEIGHTS TO PERSIST ACROSS THE
NORTHEAST PACIFIC WITH A SERIES OF FAST MOVING SHORT WAVES RIDING
OVER THE TOP OF THIS RIDGE. THIS RESULTS IN AN ACTIVE AND
CHANGABLE PATTERN FOR THE PANHANDLE THROUGH THE PERIOD. WITH
SYSTEMS MOVING THROUGH SO FAST WILL SEE SEVERAL CHANGES WITHIN 1
24 HOUR PERIOD WHERE SNOW CHANGES TO RAIN AND BACK TO SNOW AGAIN.
USED 06Z GFS FOR GRIDS THROUGH 102 HOURS THEN A MODIFIED GFSLR.

985 MB LOW NEAR PRINCE WILLIAM SOUND THURSDAY NIGHT CONTINUES
NORTH. SECOND WRAP OF OCCLUSION SLAMS THE NORTH COAST WITH
ADVISORY LEVEL WINDS AND HEAVY RAIN. TEMPERATURES CLIMBING WELL
ABOVE NORMAL AT THIS TIMES AND EXPECT RAIN OR SNOW TURNING TO
RAIN FOR THE FAR NORTH. AS THIS LOW LIFTS NORTH INTO THE INTERIOR
FRIDAY A SMALL RIDGE AND COLDER AIR MASS SPREAD ACROSS SOUTHEAST
ALASKA WITH RAIN SHOWERS TURNING TO SNOW BY FRIDAY NIGHT.

NEXT LOW LIFTS OUT OF THE NORTH PACIFIC AND INTO CENTRAL GULF
AT990 MB FRIDAY NIGHT THEN WEAKENING AS IT MOVES ACROSS NORTHERN
PANHANDLE SATURDAY. ENOUGH COLD AIR IN PLACE AHEAD OF THIS LOW TO
START PRECIP OUT AS SNOW BUT EXPECTED TO TURN BACK TO SOUTHERN
ZONES STILL UNDER RIDGE MOST OF SATURDAY FOR ONLY CHANCE OF
SHOWERS.

STRONGEST LOW OF WEEK ROLLS THROUGH THE WESTERN GULF WHILE
DEEPENING TO 965 MB. EXPECT STORMS IN SOUTHERN AND NORTHERN QUADS
OF THIS LOW WITH GALES REMAINDER COASTAL WATERS AND PROBABLY SOME
OF THE INNER CHANNELS. GENERATED ADVISORY LEVEL WINDS IN GRIDS
FOR MOST ZONES BETWEEN SATURDAY AND SUNDAY NIGHT. TEMPERATURES
WITH THIS LOW REACH INTO 40S SOUTH AND UPPER 30S NORTH. RAIN
LIKELY HEAVY AT TIMES MOST AREAS.

ADDITIONAL SYSTEMS MOVE ACROSS THE AREAS SUNDAY THROUGH TUESDAY
WITH SMCR TO GALE FORCE WINDS. SOME TENDENCY FOR DRYING AND
COOLER CONDITIONS EASTERN GULF COAST AND FAR NORTH.

.AJK...WATCHES/WARNINGS/ADVISORIES
PUBLIC...WINTER STORM WATCH AKZ017>021-025 WED EVE-THU MORNING
      ...SNOW ADVISORY AKZ024-026 NOON TO MIDNIGHT WED NIGHT
      ...WIND ADVISORY AKZ017-022-023-027>029 MOST 4PM WED-4AM
           THU

MARINE...GALE WARNING PKZ036-041>043-051-052-310
      ...SMALL CRAFT ADVISORY PKZ011>013-021-022-031>035

BMB/MM