Gale Warning 59, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
643 AM AKST MON JAN 28 2013

.SHORT TERM...MONDAY STARTS OFF WITH TEMPERATURES CONTINUING TO
FALL AS AN ARCTIC FRONT PUSHES SOUTH. THE LOW THAT HAS BEEN
CAUSING SNOW SHOWERS ACROSS THE REGION IS NOW OVER THE SOUTHERN
PANHANDLE IN A CAPE DECISION TO PETERSBURG LINE. AS A RESULT THE
CENTRAL PANHANDLE IS STILL SEEING SOME SCATTERED SNOW SHOWERS THIS
MORNING AND THE SOUTH IS GETTING MORE PERSISTENT SNOWFALL.
TEMPERATURES TO THE SOUTH OF THE LOW/TROUGH AXIS ARE STILL ABOVE
FREEZING AND THUS SOME MIXING WITH RAIN IS POSSIBLE THIS MORNING.
AS THE LOW CONTINUES TO SHIFT SSE PRECIP WILL DIMINISH AND THE
ARCTIC BOUNDARY WILL FOLLOW. KAKE SAW THE WIND SHIFT FROM SOUTHERLY TO
NORTHERLY EARLY THIS MORNING AND TEMPERATURES QUICKLY DROPPED
FROM 32 TO 25F. THE REST OF THE AREA WILL SEE A SIMILAR SHIFT ONCE
THE LOW PASSES.

OVER THE NORTH STRONG WINDS CONTINUE AND TEMPERATURES ARE DOWN TO
ZERO. ELDRED ROCK IN NORTHERN LYNN CANAL HAS BEEN BLOWING 50KT ALL
NIGHT WITH GUSTS IN THE MID 70S. AS A RESULT HAVE GONE WILL A MORE
DEVELOPED SEA IN ALL OF LYNN CANAL AND CONTINUED WITH HEAVY
FREEZING SPRAY. HAINES AND SKAGWAY ARE SEEING SIMILAR GUSTS AND
THEREFORE HAVE CONTINUED THE WINTER WEATHER ADVISORY FOR WIND
CHILLS OF 30-40 BELOW THROUGH MIDNIGHT TONIGHT. AREAS OF BLOWING
AND DRIFTING SNOW ARE ALSO OF CONCERN FOR THE HIGHWAYS.

MANY OTHER LOCATIONS HAVE MENTION OF GUSTY NORTH WINDS TODAY
OUT OF INTERIOR PASSES. COLD WIND CHILLS OF 20 BELOW ZERO ARE
LIKELY IN THESE AREAS TOO. THE ADJACENT MARINE AREAS HAVE GALE
WARNINGS IN EFFECT AND RISK OF FREEZING SPRAY THROUGH TONIGHT.

BREAKS IN THE CLOUD COVER WITH SOME SUNSHINE THIS AFTERNOON WILL
GIVE WAY TO INCREASING HIGH CLOUDS TONIGHT. A FRONT APPROACHING
FROM THE WSW WILL MOVE INTO THE COAST LATE TONIGHT. WITH ALL THE
COLD AIR IN PLACE AND WARM AIR ALOFT WITH THE FRONT...AN
OVERRUNNING EVENT IS IN STORE. HAVE ISSUED A WINTER STORM WARNING
FOR YAKUTAT TO SITKA AND INLAND TO JUNEAU AND WRANGELL. HAINES IS
NOT IN THE WARNING AREA. EXPECTING THE SNOW TO START SLOWLY
OVERNIGHT AS THE STRONG NORTH WINDS WILL HAVE HAD A SIGNIFICANT
DRYING EFFECT DURING THE DAY AND WILL STILL BE ADVECTING IN DRY
AIR AT THE START OF THE EVENT. THIS WILL MAKE FOR LOWER SNOW
RATIOS THAT WOULD OTHERWISE BE EXPECTED WITH 90% OF THE ATMOSPHERE
WILL BE IN THE PRIME DENDRITIC SNOW GROWTH ZONE OF -10 TO -20C.
HAVE ABOUT 2-4 INCHES OF SNOW OVERNIGHT THEN CONTINUING INTO
TUESDAY. THE WARMER AIR WILL EFFECT THE FAR SOUTHERN OUTER COAST
FIRST. TEMPERATURES ALOFT APPROACH THE MELTING POINT WHILE THE
SURFACE REMAINS BELOW FREEZING. THEREFORE HAVE INCLUDED A SLIGHT
CHANCE OF FREEZING RAIN LATE TONIGHT FOR THE KLAWOCK/CRAIG/HYDABURG ZONE.

USED MAINLY THE NAM12 TODAY FOR ITS GOOD PRESSURE INITIALIZATION
OF THE INNER CHANNELS. ADJUSTED WINDS FURTHER WITH SOME OF THE
MESOSCALE MODELS. FORECAST CONFIDENCE IS AVERAGE.

&&

.LONG TERM / TUESDAY THROUGH SUNDAY /...THE MAIN ITEM IN THE
FORECAST PACKAGE WILL BE THE REMAINS OF THE OVERRUNNING EVENT
MOVING NORTHEAST ACROSS THE PANHANDLE REGION. BEST COLD AIR WILL
REMAIN OVER THE NORTHERN INNER CHANNELS AS THE NORTHERLY GRADIENT
FORCING THE COLDER AIR SOUTHWARD DIMINISHES RELAXING THE WINDS
TUESDAY NIGHT INTO WEDNESDAY. A VERY LARGE WARM SECTOR IS BEING
DEVELOPED OVER THE EASTERN GULF IN THE FLOW ABOUT THE LONG WAVE
TROUGH AT OR WEST OF 160 WEST.

THE PARENT LOW OF THE SYSTEM WILL BE MOVING INTO THE BERING SEA
REGION TUESDAY CONTINUING TO PUMP WARMER AIR NORTH AND EAST ACROSS
THE PANHANDLE. THROUGH TUESDAY THERE IS TWO AREAS OF TEMPERATURE
GRADIENT... ONE IS OVER THE NORTHERN PANHANDLE AND COAST MOUNTAINS
KEEPING THE REALLY COLD AIR ON THE CANADIAN SIDE 850 MB
TEMPERATURE COLDER THAT -12 TO -15 C TO A SECONDARY BAND ABOUT 200
NM TO THE SOUTHWEST THAT RANGES FORM 0 TO -4 C. THE SNOW WILL BE
FALLING ALONG THE TEMPERATURE PACKING ALONG THE FIRST MENTION
ACROSS THE CENTRAL PANHANDLE... BUT THE SECOND BAND IS WHERE
EVERYTHING IS CHANGING OVER TO RAIN UNDER IT. WITH SUCH A GRADIENT
AS FORECAST SOUNDING ARE SHOW FAIRLY LARGE BULGES OF WARM AIR
ALOFT AHEAD OF THE SURFACE FRONT. WITH A NARROW BAND PERHAPS
LASTING A FEW HOURS WHERE IT MAY BE LIGHT FREEZING RAIN.

AS THE FRONT DISSIPATES ACROSS THE NORTHERN PANHANDLE WHAT USED
TO BE A COLD FRONT WILL LIFT INTO THE EASTERN GULF AS A TROUGH AS MID
RANGE MODELS ARE SHOWING A SIGNIFICANTLY DEVELOPING SYSTEM
SWEEPING ACROSS THE NORTH PACIFIC BUT SHOULD BE STARTING TO WEAKEN
AS IT SPREADS INTO THE WESTERN GULF TOWARDS THE WEEKEND. THE
GENERAL IDEA OF THE WARM AND WET FOR THE LATER HALF OF THE WEEK
STILL LOOKS ONLINE.

FORECAST CONFIDENCE IS AVERAGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO NOON AKST TUESDAY
     FOR AKZ017-020>024-026.
         WINTER STORM WARNING FROM 3 AM TO 3 PM AKST TUESDAY FOR AKZ025.
         STRONG WIND UNTIL 3 PM AKST THIS AFTERNOON FOR AKZ020.
         STRONG WIND THROUGH LATE TONIGHT FOR AKZ018-019.
         WINTER WEATHER ADVISORY UNTIL MIDNIGHT AKST TONIGHT FOR AKZ018-
     019.
         STRONG WIND FROM NOON AKST TODAY THROUGH LATE TONIGHT FOR AKZ017.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ051.
         HEAVY FREEZING SPRAY WARNING FOR PKZ011>013.
         HEAVY FREEZING SPRAY WARNING FOR PKZ031.
         STORM WARNING FOR PKZ012.
         GALE WARNING FOR PKZ011-013-021-022-031-033-035-043-051>053.
         SMALL CRAFT ADVISORY FOR PKZ032-034-041-042.

&&

HANNON/BEZENEK