Small Craft Advisory 2, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
142 PM AKST WED DEC 31 2008

.SHORT TERM...THE DEEP LOW THAT PASSED JUST SOUTH OF QUEEN
CHARLOTTE ISLAND LAST NIGHT CONTINUES TO WEAKEN AS IT MOVES INTO
B.C. THE VERY NORTHERN FRINGE OF THE STORM CONTINUES TO BRING
LIGHT SNOW TO PAPG PAKT AND PAHY. AS THE STORM CONTINUES TO MOVE
EAST EXPECT THE SOUTHERN ZONES TO SCATTER OUT THIS EVENING. A
VERY COLD NIGHT ON TAP FOR THE ENTIRE SE PANHANDLE WITH
TEMPERATURES NEARLY AS COLD AS LAST NIGHT FOR NORTHERN ZONES AND
3 TO 5 DEGREES COLDER TONIGHT FOR SOUTHERN ZONES. PAYA WILL BE
SEVERAL DEGREES WARMER TONIGHT AS CLOUDS AND LIGHT SNOW MOVE INTO
THE AREA. 1 TO 3 INCHES OF SNOW IS EXPECTED IN PAYA TONIGHT AND
TOMORROW.

 WINDS OUT OF INTERIOR BAYS AND PASSES ARE DIMINISHING IN ZONE
25 BUT CONTINUE IN ZONE 18 WHERE BOTH A WIND ADVISORY AND A WIND
CHILL ADVISORY REMAIN IN EFFECT UNTIL 6 AM AKST THURSDAY. BRUTAL
WIND CHILLS TO MINUS 35 CONTINUE NEAR WHITE PASS. VERY COLD
TEMPERATURES AGAIN TONIGHT IN WIND SHELTERED AREAS SUCH AS THE
MENDENHALL VALLEY AND THE CHILKAT VALLEY. FREEZING SPRAY WILL
AGAIN BE AN ISSUE FOR NORTHERN INNER CHANNELS.

 &&

.LONG TERM...MODELS WERE IN FAIR AGREEMENT FOR THE START OF THE
LONG TERM PERIOD. THERE WERE SOME DIFFERENCES IN THE STRENGTH AND
LOCATION OF THE LOW IN THE N GULF. USED A BLEND OF THE INHERITED
GRIDS WITH THE 12Z GFS40 AS IT KEEP THE LOW A BIT STRONGER THAN THE
EC. AFTER DAY 4 THE MODEL SOLUTIONS DIVERGE DEALING WITH LOW IN
THE N PACIFIC. THE GFS KEEPS THE LOW STRONGER AND ON A SOUTHERLY
TRACK WITH THE EC KEEPING THE LOW WEAKER HAVING A SECONDARY LOW
FORM IN THE N GULF. USED A BLEND OF HPC GUIDANCE AFTER DAY 4 WHICH
LEANED MORE TOWARDS THE EC.

LONG WAVE TROUGH WILL FLATTEN INTO THE WEEKEND TRANSITIONING TO
ZONAL FLOW. LONG WAVE PATTERN WILL TRANSITION AGAIN WITH ANOTHER
TROUGH MOVING OVER THE GULF AT THE START OF NEXT WEEK. THE BRIEF
BREAK IN WINDS FOR THE N ZONES EXPECTED THURSDAY WILL END AS WINDS
BEGIN TO INCREASE AGAIN. THE LOW IN THE EASTERN GULF BEGINS TO
STRENGTHEN AGAIN TO 990 MB AND WITH HIGH PRESSURE ALONG THE
INTERIOR WILL NEAR ADVISORY LEVELS WINDS AGAIN WITH GALE FORCE
WINDS IN THE N INNER CHANNELS. KEPT HEAVY FREEZING SPRAY IN THESE
MARINE ZONES AS AIR AND SEA TEMPS WILL ALSO REMAIN LOW. WITH THE
NORTHERLY FLOW AND STRONG OUTFLOW WINDS WILL KEEP ARCTIC AIR OVER
THE REGION. WITH THE FRONT EXPECTING SNOW FOR THE SOUTHERN AND
CENTRAL PANHANDLE. WITH THE JET TO THE SOUTH NOT EXPECTING TOO
MUCH MOISTURE INFLOW AND WEAK UPPER LEVEL FORCING. MOST PRECIP
WILL BE DUE TO OVERRUNNING OF ARCTIC AIR AT THE SURFACE. DROPPED
SNOW AMOUNTS A BIT BUT STILL CLOSE TO ADVISORY LEVEL SNOW FALL FOR
CENTRAL PANHANDLE.

FORECAST CONFIDENCE FOR THE START OF THE LONG TERM IS SLIGHTLY
BELOW AVERAGE WITH SOME UNCERTAINTY IN SNOW AMOUNTS FOR THE
WEEKEND. FOR THE REMAINED OF THE LONG TERM FORECAST CONFIDENCE IS
LOW WITH MODEL DIVERGENCE AND PATTERN CHANGE.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 6 AM AKST THURSDAY FOR AKZ018.
         WIND CHILL ADVISORY UNTIL 6 AM AKST THURSDAY FOR AKZ018.
MARINE...HEAVY FREEZING SPRAY WARNING FOR PKZ011-012.
         HEAVY FREEZING SPRAY WARNING FOR PKZ013.
         GALE WARNING FOR PKZ011>013-021-022-031-032-034.
         SMALL CRAFT ADVISORY FOR PKZ033-035-036-041-051.

&&

CCC/PRB