Gale Warning 106, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
620 AM AKST SAT FEB 21 2009

.SHORT TERM...EARLY MORNG STLT LP SHOWS A WEAK LO IN THE NE GULF
WITH A WEAK SFC TROF XTNDG SE OVR NRN PANHANDLE COAST. AN
INVERTED SFC TROF OF LO PRES OVR SE GULF PUSHES PCPN BAND NEWD
AND INTERACT WITH THE WEAKNG LO IN THE NE GULF. MDLS ARE IN GOOD
AGRMNT WITH THE WEAKNG LO IN THE NE GULF MOVG SE THRU EARLY THIS
AFTN THEN DISSIPATE W OF DIXON ENTRANCE AS A DEVELOPING LO IN THE
NE PAC CONTINUES TO PUSH A FRONTAL BNDRY INTO THE SE GULF. BEHIND
THE DISSIPATING LO...HI PRES BUILDS OVR THE NWRN CANADA. THIS
WILL INCREASE PRES GRADNT SIGNIFICANTLY ACRS THE NRN PANHANDLE
AND ENHANCE OFFSHORE FLOW ACRS THE SE AK. PREFERRED TO LEAN OVR
THE 06Z RUN NAM12 SOLUTIONS BLENDED INTO THE INHERITED GRIDS.

 INTERACTION BTWN THE WEAKNG SFC TROF IN THE NE GULF AND INVERTED
TROF FM THE S...WILL ENHANCE PCPN ACRS THE SRN PANHANDLE...S OF
PAPG THRU THIS EVENG WITH 1 TO 2 INCHES OF SNOW EXPECTED. AS THE
DEVELOPING LO IN THE NE PAC PUSHES A FRONTAL BOUNDARY INTO THE SE
GULF THIS EVENG...PCPN BAND ACRS THE SRN PANHANDLE WILL MOVE
FARTHER SE AWAY FROM THE LCL RGN. BLDG HI PRES IN THE NWRN CANADA
WILL PUSH THE TROF OF LO PRES IN THE SE GULF SUB-PRESSED AND
INCREASE PRES GRADNT ACRS THE PANHANDLE. OFFSHORE FLOW WILL CONT
TO BE ENHANCED TONITE. THIS WILL CAUSE WINDY CONDS FM E OF PAYA
TO PAGY AND PAHN AREAS...AS WELL AS ACRS THE LYNN CANALS. GALE
FORCE WNDS ARE EXPECTED ACRS THE NRN OUTSIDE WATERS WITH STRONG
OFFSHORE FLOW. WINDS ACROSS THE NRN PANHANDLE MAY MEET ADVISORY
LEVEL GUSTS TONITE. DAY SHIFT NEEDS TO KEEP AN EYE ON THE TREND.
&&

.AJK WATCHES/WARNINGS/ADVISORIES... PUBLIC...NONE. MARINE...GALE
WARNING FOR PKZ051.          SMALL CRAFT ADVISORY FOR
PKZ011>013-021-022-043.          SMALL CRAFT ADVISORY DUE TO SEAS
FOR PKZ041-042.
&&

.LONG TERM...MODELS CONTINUE FAIRLY CONSISTENT THROUGH EARLY NEXT
WEEK...DEVELOPING A CUT-OFF LOW ALOFT IN THE PACIFIC SOUTH OF THE
PANHANDLE WHILE BUILDING AN UPPER RIDGE OVER INTERIOR ALASKA ON
SUNDAY...THEN DRIFTING THE TROUGH AND RIDGE SLOWLY EASTWARD
THROUGH TUESDAY. AFTER THAT THE ENSEMBLE SPREAD GROWS
SIGNIFICANTLY WITH DIFFERENCES IN THE INTENSITY AND SPEED OF SHORT
WAVES ADVANCING THROUGH THE RIDGE FROM THE WEST. THE OPERATIONAL GFS
AND ECMWF REFLECT A SIMILAR DIVERGENCE DURING THIS PERIOD. AS A
RESULT OF THE HIGH UNCERTAINTY IN THE FORECAST PATTERN FOR THE
END OF THE WEEK FEW CHANGES WERE MADE TO THE PREVIOUS TREND OF
KEEPING A STRONGER UPPER RIDGE WITH MINOR SHORTWAVES MOVING
THROUGH IT.

AT THE SURFACE...BUILDING ARCTIC HIGH PRESSURE IN THE YUKON WILL
PUSH INTO NORTHERN SOUTHEAST ALASKA BRINGING GALE WINDS AND
COLDER TEMPERATURES ON SUNDAY. LINGERING SNOW FLURRIES IN THE
SOUTHERN PANHANDLE WILL DISSIPATE AS THE ARCTIC OUTFLOW SPREADS
OVER THE REMAINDER OF THE AREA ON MONDAY. DRY CONDITIONS WILL THEN
PERSIST THROUGHOUT THE PANHANDLE UNTIL AT LEAST MID WEEK WHEN THE
UPPER RIDGE BEGINS TO WEAKEN AND TIP EASTWARD.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ051.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-043.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041-042.
&&

SJA/CFD