Gale Warning 138, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
433 PM AKST THU MAR 6 2014

.SHORT TERM...A LOW PRESSURE SYSTEM WILL MOVE UP INTO THE
CENTRAL GULF THROUGH FRIDAY AND FRIDAY NIGHT. THE FRONTAL BAND
WILL BRING PRECIPITATION TO THE SOUTHERN COAST LATE TONIGHT AND
TO THE JUNEAU AREA LATE FRIDAY AFTERNOON/EARLY EVENING. EXPECT
THE HAINES AND SKAGWAY AREAS TO SEE SNOW BEGINNING A FEW HOURS
LATER. EVERYWHERE WILL START OFF AS SNOW THEN SLOWLY CHANGE TO
RAIN AS THE SYSTEM BRINGS IN WARM AIR ALOFT. GREATEST SNOWFALL
AMOUNTS LOOK TO BE IN THE HYDER AREA, THE ICY STRAIT CORRIDOR
INCLUDING JUNEAU, HAINES AND SKAGWAY. WATCHES AND ADVISORIES HAVE
BEEN ISSUED FOR ALL OF THESE AREAS. PLEASE SEE THE ASSOCIATED
STATEMENTS FOR MORE DETAILS ON AMOUNTS.

 GUSTY WINDS WILL ARRIVE WITH THE FRONT. THE SOUTHERN OUTER COAST
UP  TO CROSS SOUND AND KETCHIKAN WILL SEE WIND GUSTS OF AROUND
40 MPH  FRIDAY AFTERNOON OUT OF THE SOUTHEAST. THE REST OF THE
PANHANDLE  WILL SEE MAINLY NELY WINDS TONIGHT AND FRIDAY AS THE
LOW APPROACHES  FROM THE SOUTH. THEN WINDS OVER THE CENTRAL INNER
CHANNELS WILL FLIP  TO THE SOUTH THROUGH FRIDAY NIGHT. GUSTY SELY
WINDS CAN BE EXPECTED  WITH THIS WIND SHIFT.

 MODELS CONTINUE TO HAVE DIFFERENCES WITH PLACEMENT OF THE LOW
CENTER  AS IT MOVES INTO THE GULF OF ALASKA. THE GEM/NAM/GFS HAD
THE BEST  CONSENSUS FOR THE LOW CENTER SO THOSE WERE USED CHANGES
TO THE  PRESSURE AND RESULTING WIND FIELD. FORECAST CONFIDENCE IS
ABOVE  AVERAGE ON THE ARRIVAL OF OUR MARCH STORM...BUT SLIGHTLY
LOWER ON  THE DETAILS DUE TO MODEL DIFFERENCES THIS CLOSE IN
TIME.

 .LONG TERM...VOLATILE FORECAST, AS NONE OF THE MODELS DOING A
PARTICULARLY GREAT JOB OF RAISING CONFIDENCE IN OUR FORECAST.
THIS PERTAINS TO WIND IN PARTICULAR...BUT COULD ALSO INFLUENCE
SNOW TOTALS.

 CONFIDENCE VERY GOOD FOR WET WEEKEND...THAT INCLUDES SNOW
TRANSITIONING TO RAIN FOR THE CENTRAL PANHANDLE SATURDAY MORNING.
MIXING IN WITH RAIN AT TIMES LATE IN THE WEEKEND FOR LYNN
CANAL...AND A SOLIDLY WET DAY FOR THE SOUTHERN PANHANDLE FOR
SATURDAY INTO THE WEEKEND. AT THIS POINT, WE FEEL AS IF THE
SOUTHERN PANHANDLE WILL HAVE A GOOD FRONTAL PASSAGE LIFT
NORTHWARD FOR SATURDAY. 75 KT SOUTHERLIES BY THE NAM AT 850 MB
CONVINCED US TO GO GALE IN STEPHENS PASSAGE. WARM AIR ADVECTION
STRONG WINDS TEND TO REMAIN ALOFT, BUT GIVEN OUR COMPLEX TERRAIN
AND WARMING TEMPERATURES ALL AROUND...FEEL AS IF SOME MIXING WILL
MIX AT LEAST A GOOD PORTION OF THESE TO THE SURFACE. LAND WINDS
COULD POTENTIALLY BE UNDERFORECAST SATURDAY MORNING. GRADIENTS
FOR SOME MODELS SUGGESTING STRONG WIND FOR JUNEAU, BUT OTHERS NOT
SO MUCH, SO HAVEN'T GONE THERE YET.

 LYNN CANAL WILL BE A TRICKY FORECAST, AS ECMWF TAKING WARM AIR
SURGE NORTHWARD, AND LIKELY TURNING THEM TO RAIN EARLY AND THUS
BLOWING OUR COOLISH TEMPERATURE FORECAST, BUT HAVE OTHER MODELS
SUGGESTING MORE NORTHERLY GRADIENTS UP THERE, SO HAVE FUDGED.
KEPT TEMPERATURES COOL, BUT IF WINDS GO SOUTHERLY IN A BIG
WAY...AS DOWN SOUTH, WINDS COULD BLOW STRONGLY FROM SOUTH AND
TEMPERATURES RISE ENOUGH TO CHANGE OVER THE SNOW EARLY.

 NEXT WEEK LOOKS WET AND WARM WITH SOUTHERLY FLOW OVER THE
PANHANDLE.  SPRING SPRINGING?

 CONFIDENCE IN FORECAST ON POOR SIDE OF AVERAGE GIVEN INSTABILITY
OF MODELS FOR WINDS/TEMPERATURES/CHANGEOVER TO RAIN NORTHERN
PANHANDLE. AVERAGE CONFIDENCE FOR TYPICAL SITUATIONAL FRONTAL
PASSAGE OVER PANHANDLE. CONFIDENCE ABOVE AVERAGE FOR VERY WET
WEEKEND. USED COMBO OF GEM/NAM/GFS THROUGH SAT NIGHT...THEN
TRANSITIONED TO GFS/EC INTO SUNDAY NIGHT. NEXT WEEK FORECAST
UNCHANGED.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND FRIDAY AFTERNOON FOR AKZ027-028.
         WINTER STORM WATCH FROM FRIDAY EVENING THROUGH SATURDAY MORNING
     FOR AKZ020>022-025.
         STRONG WIND FRIDAY AFTERNOON FOR AKZ022-023.
         WINTER WEATHER ADVISORY FROM 5 AM FRIDAY TO 5 AM AKST SATURDAY
     FOR AKZ029.
         WINTER STORM WATCH FROM FRIDAY EVENING THROUGH SATURDAY EVENING
     FOR AKZ018-019.
         WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM AKST FRIDAY
     FOR AKZ018.
MARINE...GALE WARNING FOR PKZ011>013-021-022-035-036-042-043.
         SMALL CRAFT ADVISORY FOR PKZ031>034-041-051>053.

&&

FERRIN/JWA