Gale Warning 101, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
253 PM AKST THU FEB 4 2010

.SHORT TERM...

.SHORT TERM...COMPLEX LOW 600 NM S OF PAKT AT THIS TIME
HAS IR SIGNATURES THAT QUALITATIVELY INDICATE A CYCLOGENESIS
SMALLER AND MORE CONCENTRATED THAN ANY OF THE NWP. THE
NAM12 CAME THE CLOSEST TO HAVING THE ROUGHLY 975 MB LOW
WITHIN 100 NM OF THE OUTER COAST OF THE PNHDL TRACKING
ALONG TO THE NW FRI.  PLEASE NOTE THE HIGH WIND WATCH
FOR ZONE 27 AS WELL AS THE WINDS IN COASTAL MARINE ZONES.

PRIOR TO THE ABV EVENT: SFC TROUGH XTDG E ACRS NRN PNHDL
MOVG N INTO CAN. PRESSURE WAVES TRACKING NNW ALONG THE PNHDL
WILL DIRECT THE CHANGES IN WIND TO BE FM GEN NE FLOW TO
GEN SE FLOW AND BACK THIS AFTERNOON AND TONIGHT.

 .LONG TERM...MODELS STARTING TO COME MORE IN LINE FOR THE LONG
TERM BUT STILL SEEING SOME DIFFERENCES OUT TO DAY 4...MAINLY
DEALING WITH TRIPLE POINT LOW ON DAY 3 WITH ASSOCIATED FRONTAL
BAND MOVING OVER THE PANHANDLE. OTHER ISSUES ARE WINDS DURING
HAND OFF PERIOD WITH ADV GUSTS CONTINUING IN ZONES 23 AND 28 AND
IF WARNING CRITERIA IN ZONE 27 WILL DEVELOP. FOR THE REMAINDER OF
THE LONG TERM MODELS WERE IN FAIR AGREEMENT OVER OUR AREA.

AS REMNANTS OF GULF LOW MOVE NORTHWEST TRIPLE POINT LOW FORMATION
IS WELL DEVELOPED IN THE GFS...WITH WEAKER OPEN TROUGH SHOWN IN
NAM AND CRAS. ECMWF SHOWING LITTLE DEVELOPMENT AND APPEARS TO BE
THE OUTLIER FOR THAT TIME PERIOD. TONED DOWN THIS LOW DEVELOPMENT
BY BLENDING GFS WITH INHERITED GRIDS AND NAM12. TEMPERATURES
DURING THIS TIME WERE DROPPED SIGNIFICANTLY BY THE GFS SO CHANCES
OF A SNOW EVENT SIGNIFICANTLY IMPROVED. NAM TEMPS WELL IN THE SNOW
DEVELOPMENT RANGE BUT NOT QUITE AS COLD AS GFS. QPF VALUES WHILE
RAISED A BIT FOR THIS TIME STILL BACKED OFF A BIT. SO SNOW AMOUNTS
WERE KEPT IN THE 1 TO 3 INCH RANGE OVER 24 HOURS WITH SOME
UNCERTAINTY REMAINING.

WITH THE FRONTAL BAND MOVING OVER THE PANHANDLE WILL SEE
CONTINUING HIGH WIND GUSTS OVER THE SOUTHERN PANHANDLE AND OUTER
COAST. 850MB LLJ WITH 60 TO 70 KT WINDS MOVES FAIRLY RAPIDLY
NORTH. CONFIDENCE IN ADVY LVL GUSTS FOR ZONES 28 AND SOUTHERN
PORTION OF ZONE 23 IS ABOVE AVERAGE AS DIRECTION IS MORE SE THAN
E. NOT GREAT CONFIDENCE IN THE WARNING LVL GUSTS LASTING FOR ZONE
27 AS MODELS ARE NOT SHOWING THE LLJ QUITE STRONG ENOUGH...BUT
WITH FEATURES BEING FAIRLY CLOSE TOGETHER MODELS MAY BE WASHING
OUT DETAILS.

FOR THE REMAINDER OF THE LONG TERM PATTERN SHOWING RIDGE OVER
CANADA WITH LONG WAVE TROUGH MOVING INTO THE W GULF. MODELS IN
SOME DISAGREEMENT ON DETAILS OF SHORTWAVES SPINNING OFF INTO THE N
PACIFIC. USED A BLEND OF INHERITED GRIDS WITH HPC GUID FROM DAY 4
ONWARD. FORECAST CONFIDENCE IS STILL BELOW AVERAGE FOR THE START
OF THE LONG TERM. WHILE MODELS ARE MORE IN LINE STILL ENOUGH
DIFFERENCES TO WARRANT SOME CONCERN. REMAINDER OF THE LONG TERM
CONFIDENCE IS AVERAGE WITH OVER ALL PATTERN AND ONLY FAIR
CONCERNING DETAILS.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR
     AKZ027.
         WIND ADVISORY FROM 10 AM TO 9 PM AKST FRIDAY FOR AKZ023.
         WIND ADVISORY FROM 6 AM TO 9 PM AKST FRIDAY FOR AKZ028.
MARINE...GALE WARNING FOR PKZ036-041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.

&&

JBT/PRB