Storm Warning 76, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
234 PM AKDT SUN OCT 31 2010

.SHORT TERM...THE EXPLOSIVE CYCLOGENESIS IS NOW BEING FOLLOWED A
MORE MATURE PHASE FOR THE ROUGHLY 945 MB THAT IS 600 NM S OF PAWD
AT THIS TIME. NOTE THE LENGTHY TABLE OF WATCHES, WARNINGS, AND
ADVISORIES GIVEN BELOW. THE MATURING SYSTEM IS ON A VAST SCALE SO
THE MODELS HAVE GOTTEN A CONSENSUS THAT RESULTS IN OVERALL GOOD
CONFIDENCE.

 AGAIN THE OVERALL MODEL CONSENSUS IS GOOD. THE NAM, WRF ARE
USED AS PRIMARY GUIDANCE, ALTHOUGH A VARIETY OF OTHER MODELS  ARE
BEING APPLIED, FOR EXAMPLE THE SREF IS BEING BLENDED IN  TO THE
EXISTING POP FIELD AS IT IS A STATISTICAL MODEL.

&&

 .LONG TERM...ACTIVE FALL WEATHER PATTERN CONTINUES THROUGH THE
LONG TERM FORECAST PERIOD. SUNDAYS STORM FORCE WIND WILL CONTINUE
TO TRACK NORTHWARD TOWARD PRINCE WILLIAM SOUND MON EVENING
WEAKENING TO AROUND 965 MB. STRONG WINDS WITH ADVY LEVEL GUSTS
FROM THE SECONDARY WRAP WILL DIMINISH THROUGH THE EVENING. PRECIP
WILL CONTINUE MON NIGHT INTO TUE REMAINS ALL LIQUID WITH WARM AIR
PUSHING UP FORM THE SOUTH. THE LOW WILL THEN MOVE INTO THE AK
INTERIOR AS A RIDGE OF HIGH PRESSURE BUILDS OVER THE PANHANDLE.
AS NORTH SOUTH PRESSURE GRADIENT INCREASES SOUTHERLY WINDS OVER
THE NORTHERN ZONES WILL INCREASE TO ADVY LEVELS. THE UPPER LEVEL
TROUGH BECOMES NEGATIVELY TILTED WITH LOW PRESSURE SYSTEM MOVING
UP FROM THE PACIFIC MID WEEK. STILL FAIR AMOUNT OF UNCERTAINTY
WITH THE RESOLUTION OF THIS SYSTEM. FOR TUE INTO WED SEEING LOWER
POPS AS MID LEVEL FLOW SHIFTS MORE TO THE SOUTHEAST BEFORE NEXT
FRONTAL BAND MOVES UP FORM THE SOUTH WITH LIKELY TO CATEGORICAL
POPS. SOUTHERN ORIENTED UPPER LEVEL JET WILL BRING LONG FETCH OF
MOISTURE WITH HEAVY RAIN. AS FIRST FRONT ASSOCIATED WITH THE MID
WEEK LOW MOVES UP A 60 TO 70 KT LLJ FORMS BRINGING INCREASED
WINDS OVER THE AK GULF WITH ADVY TO POSSIBLE WARING LVL GUSTS
ALONG THE COASTAL ZONES. HOWEVER AS OPERATIONAL MODEL RUNS HAVE
BEEN INCONSISTENT WITH THIS LOW SOME SHOWING TWO SEPARATE CENTERS
WHICH WILL BRING LIGHTER WINDS. AS THIS MID WEEK SYSTEM TRACKS
NORTH RIDGE BUILDS OVER THE PANHANDLE AS ANOTHER LOW TRACKS SOUTH
OF THE ALEUTIANS EASTWARD TOWARDS THE WESTERN AK GULF FOR THE
WEEKEND...HOWEVER STILL FAIR AMOUNT OF UNCERTAINTY WITH THIS.

 MODELS STARTED IN FAIR AGREEMENT AT THE START OF THE LONG TERM
UT THEN DIVERGE BY MID WEEK. STILL SOME MINOR DIFFERENCES IN
STRENGTH OF THE DISSIPATING LOW MON EVENING BUT AS NEW RUNS WERE
CLOSE TO OFFICIAL GRIDS ONLY MINOR CHANGES WERE MADE. GFS HAS
BEEN FAIRLY CONSISTENT RUN TO RUN. 00Z EC WAS SIGNIFICANTLY
DIFFERENT FROM PREVIOUS EC RUNS AND THE GFS WHILE THE NEW 12Z EC
WAS CLOSER TO PREVIOUS RUN AND THE GFS. FOR MID WEEK USED HPC
GUID WHICH USED A BLEND OF ENSEMBLE MEANS AS OPERATIONAL MODELS
DETAILS WERE STILL QUITE VARIABLE. FORECAST CONFIDENCE IS ABOUT
AVERAGE FOR THE START OF THE LONG TERM BUT QUICKLY DROPS MID
WEEK.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WIND ADVISORY UNTIL 1 AM AKDT MONDAY FOR AKZ026.
         HIGH WIND WARNING UNTIL 10 PM AKDT THIS EVENING FOR AKZ027.
         WIND ADVISORY UNTIL 10 PM AKDT THIS EVENING FOR AKZ021-024-025.
         WIND ADVISORY UNTIL 10 PM AKDT MONDAY FOR AKZ022-023-028.
         WIND ADVISORY UNTIL 1 AM AKDT MONDAY FOR AKZ029.
         WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 4 AM AKDT
     MONDAY FOR AKZ019.
         WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM AKDT MONDAY
     FOR AKZ018.
         WIND ADVISORY FROM 7 AM TO 10 PM AKDT MONDAY FOR AKZ017.
MARINE...STORM WARNING FOR PKZ036-041>043-051-052.
         GALE WARNING FOR PKZ011>013-021-022-031>035.

&&

JBT/PRB