Small Craft Advisory 142, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
443 PM AKST MON FEB 10 2014

.SHORT TERM...COMPLEX WEATHER PATTERN WITH LOTS OF VARIABLES.
FIRST OFF IS THE STRONG NORTHERLY WINDS. THESE ARE BEING CAUSED
BY HIGH PRESSURE IN THE YUKON AND A LOW OVER HAIDA GWAII. STILL
HAVE THE HIGH WIND WARNING IN EFFECT FOR THE JUNEAU ZONE UNTIL
9 PM TONIGHT. STRONGEST WINDS HAVE BEEN SOUTH OF DOWNTOWN.
NORTHERN LYNN CANAL HAS BEEN SUSTAINED STORM FORCE WINDS WITH
HURRICANE FORCE GUSTS OF 70-75KT. OTHER AREAS ARE ALSO SEEING
STRONG WIND GUSTS OUT OF INTERIOR PASSES.

 THE LOW TO THE SOUTH HAS A FRONTAL BAND WRAPPING AROUND IT AND
IS CAUSE SNOW TO FALL AS FAR NORTH AS WRANGELL. THE KETCHIKAN
AREA IS UNDER A WINTER WEATHER ADVISORY WHICH HAS BEEN EXTENDED
UNTIL 1 AM TONIGHT. EXPECT 3 TO 5 INCHES STORM TOTAL SNOW THERE.
THE LOW WILL MOVE OFF TO THE EAST INTO BRITISH COLUMBIA OVERNIGHT
AND FILL. CLOUDS WILL DECREASE OVER THE SOUTHERN AREAS THROUGH
TUESDAY MORNING...BUT ONLY BRIEFLY. A SECOND LOW WILL TRACK
EASTWARD ACROSS THE NORTH PACIFIC TOWARD HAIDA GWAII..IN A VERY
SIMILAR PATH AS THE FIRST LOW. SNOW ASSOCIATED WITH THIS LOW WILL
BEGIN AROUND MID DAY AND CONTINUE INTO THE LONG RANGE PERIOD. A
WINTER STORM WATCH HAS BEEN ISSUED FOR THE SOUTHERN ZONES...SEE
THE LONG TERM SECTION FOR MORE DETAILS.

 THERE WILL BE A SLIGHT DECREASE IN THE WINDS OVERNIGHT BETWEEN
LOW PRESSURE SYSTEMS AS THE OVERALL PRESSURE GRADIENT WILL
SLACKEN. THEN EXPECT MORE GUSTS TUESDAY AFTERNOON...BUT NOT
NEARLY AS STRONG AS TODAY.

 850MB TEMPERATURES OVER THE NORTH ARE COOLING AND MODERATING
OVER THE SOUTHERN ZONES. FOR THE NORTHERN THIRD OF THE
PANHANDLE...EXPECT MINIMUM TEMPERATURES TO BE SLIGHTLY COLDER
THAN LAST NIGHT UNDER CLEAR SKIES. SAME GOES FOR MAX TEMPERATURES
TOMORROW...EXPECT THEM TO BE SLIGHTLY LOWER THAN WHAT THEY
REACHED TODAY. OVER THE SOUTHERN ZONES THE LOWS WILL BE FAIRLY
CLOSE TO LAST NIGHT AS THERE WILL BE BREAKS IN THE CLOUDS DURING
THE COLDEST PART OF THE MORNING. HIGH TEMPERATURES WILL WARM NEAR
FREEZING...AND ABOVE FREEZING SOUTH OF HYDABURG SO SOME MIXED
PRECIP IS POSSIBLE THERE TUESDAY AFTERNOON.

 USED AN ENSEMBLE APPROACH FOR UPDATES AND SOME HIGH RES MODELS
FOR THEIR DETAILS. OTHER CHANGES WERE FOR LOCAL EFFECTS AND BASED
ON THE RAPIDLY CHANGING WEATHER OVER THE SOUTHERN ZONES. FORECAST
CONFIDENCE IS ABOVE AVERAGE.

&&

.LONG TERM...WEATHER SYSTEM CURRENTLY OVER THE SOUTHERN PANHANDLE
AND PRODUCING ACCUMULATING SNOW WILL HAVE JUST CLEARED THE
FORECAST AREA AS ANOTHER SYSTEM APPROACHES FROM THE WEST TUESDAY
NIGHT. HAVE ISSUED A WINTER WEATHER WATCH FOR THIS EVENT FOR THE
SOUTHERN THIRD OF THE PANHANDLE. 24 HOUR SNOW TOTALS RANGING FROM
4 INCHES NEAR KAKE TO 10 INCHES IN HYDER. HIGHER AMOUNTS GENERALLY
SOUTH AND EAST. THE TUESDAY NIGHT EVENT WILL ADVECT SOME WARMER
LOW LEVEL AIR ON WEDNESDAY AND DRIVE THE ARCTIC FRONT NORTH.
ADDITIONAL SHOTS OF LOW LEVEL WARM AIR ADVECTION THURSDAY NIGHT
THROUGH SATURDAY WILL AIDE IN DISPLACING THE VERY COLD NEAR
SURFACE AIRMASS CURRENTLY OVER SOUTHEAST ALASKA. LOOK FOR HIGHS
RANGING FROM THE MID 30S TO THE LOW 40S BY NEXT WEEKEND WITH LOWS
IN THE MID 20S TO LOW 30S.

BETWEEN THEN AND NOW, VERY STRONG OUTFLOW WINDS WILL CONTINUE
THROUGH MID WEEK AS A RESULT OF THE PRESSURE GRADIENT BEING
GENERATED BY LOW PRESSURE OVER THE GULF AND HIGH PRESSURE OVER
WESTERN CANADA. MORE HIGH WIND WARNINGS ARE POSSIBLE FOR LATER
THIS WEEK.

USED A BLEND OF NAM, GEM AND ECMWF EARLY ON. BLENDED ECMWF WITH
WPC IN THE MID RANGE...WITH PROGRESSIVELY MORE WPC. POP PRIMARILY
FROM ECMWF WITH SOME GFS AND GEM. QPF FROM ECMWF AND RFC. FORECAST
CONFIDENCE IS AVERAGE.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
     MORNING FOR AKZ026>029.
         HIGH WIND WARNING UNTIL 9 PM AKST THIS EVENING FOR AKZ025.
         STRONG WIND UNTIL MIDNIGHT AKST TONIGHT FOR AKZ017-025.
         WINTER WEATHER ADVISORY UNTIL 1 AM AKST TUESDAY FOR AKZ028.
         STRONG WIND UNTIL 9 PM AKST THIS EVENING FOR AKZ029.
         STRONG WIND TUESDAY AFTERNOON FOR AKZ029.
         STRONG WIND THROUGH TUESDAY MORNING FOR AKZ018-019.
         WIND CHILL ADVISORY UNTIL NOON AKST WEDNESDAY FOR AKZ018.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ011.
         HEAVY FREEZING SPRAY WARNING FOR PKZ013.
         HEAVY FREEZING SPRAY WARNING FOR PKZ012-031.
         STORM WARNING FOR PKZ012.
         GALE WARNING FOR PKZ011-013-021-022-031-032-034-035-043-051.
         SMALL CRAFT ADVISORY FOR PKZ033-036-041-042.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ052.

&&

FERRIN/FRITSCH