Wind Advisory 12, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
505 AM AKST TUE JAN 26 2010

.SHORT TERM...SATELLITE IMAGERY THIS MORNING SHOWING A WEAKENING
LOW IN THE SE GULF TRACKING NW. WEAK FRONT MOVING OVER THE
SOUTHERN PANHANDLE PRODUCING LIGHT RAIN...WITH SOME SNOW SEEN
EARLIER AT PAKT. HIGH PRESSURE OVER THE YUKON STILL IN PLACE AND
SHOULD TRACK S TOWARD BC WHILE WEAKENING. OTHER MAIN FEATURE IS A
963 LOW 800 MILES SOUTH OF THE ALEUTIANS TRACKING E...THE NEXT
WEATHER MAKER. SW /NE PRESSURE GRADIENT CONTINUES TO WEAKEN WITH
THE LOW AND HIGH. PAGY WINDS HAVE REMAINED HIGH BUT HAVE NOT SEEN
THE ADVY LEVEL GUSTS CONTINUING...SO DECIDED TO CANCEL THE ADVY
WITH THE NEW PACKAGE. WINDS OVER SOUTH DOUGLAS AND DOWNTOWN JUNEAU
DROPPED OFF SIGNIFICANTLY AS WINDS SHIFTED FROM NORTHEAST TO SOUTH
EAST AND CROSS BARRIER FLOW WEAKENED. WHILE THE MORNING INVERSION
MAY BE KEEPING WINDS FROM REACHING THE SURFACE COULD NOT SEE
CONTINUED EVIDENCE TO KEEP THE AKZ25 ADVY GOING.

 AS FRONT MOVES NORTH EXPECTING PRECIP TO MOVE ACROSS THE
PANHANDLE. OFFSHORE FLOW OVER THE N PANHANDLE WILL WEAKEN AND
SHIFT. PRECIP TYPE WILL BE AN ISSUE WITH SURFACE AIR TEMPS ABOVE
FREEZING...DEW PTS BELOW FREEZING, BUT RISING. THE 12Z PANT
SOUNDING SHOWED A DEEP SATURATED LAYER WILL INTO THE -10C
ZONE...SO GOOD INDICATION OF ICE FORMATION. EXPECTING A MIXED
PRECIP IN THE AFTERNOON FREDERICK SOUND TO ICY STRAIT WITH ALL
SNOW NORTH. SHOULD SE A RETURN TO ALL SNOW ALONG THE ICY STRAIT
CORRIDOR TONIGHT. QPF VALUES LOOK FAIRLY LOW WITH SOME LOCALLY
HIGHER VALUES. SNOW ACCUMULATIONS SHOULD ONLY BE 1 TO 3
INCHES...TOWARD THE LOWER END WITH MORE RAIN MIXING IN.

 MODELS IN GOOD AGREEMENT THIS MORNING AND INITIALIZED WELL. WENT
WITH A BLEND OF NAM AND GFS TO BLEND IN WITH THE LONG TERM. NO
MAJOR CHANGES EXCEPT LOWERING WINDS A BIT EARLIER AND INCREASING
POPS FOR TONIGHT. FORECAST CONFIDENCE IS ABOUT AVERAGE.

.LONG TERM...SPLIT FLOW WILL PERSIST THROUGH THE PERIOD WITH THE
SOUTHERN STREAM DOMINATING THE AREA. A FAIRLY STRONG OCCLUDED
FRONT WILL MOVE INTO THE GULF WED THEN STALL ALONG THE OUTER COAST
WED NIGHT. LOOKS LIKE THERE WILL BE AT LEAST 1 LOW PRESSURE WAVE
RIDING N ALONG THE FRONT LATE WED NIGHT INTO FRI...BUT MODELS
DIFFER ON TIMING AND STRENGTH OF THESE WAVES. DUE TO THIS
REMAINING UNCERTAINTY...THOUGHT IT BEST TO NOT MAKE ANY RADICAL
CHANGES TO THE CURRENT FORECAST.

DID MAKE SOME MINOR CHANGES FOR WED AND WED NIGHT. MODELS IN GOOD
AGREEMENT THAT PRECIP WILL LIKELY GET NE A LITTLE FASTER THAN
PREVIOUSLY EXPECTED...SO BROUGHT HIGHER POPS INLAND A BIT WED AND
WED NIGHT. PTYPE WILL BE QUESTIONABLE DUE TO THE LOWER LEVEL NE
FLOW OVER THE NORTHERN AREA WED INTO THU. LOOKS LIKE MAINLY SNOW FAR
N AND A MIX FOR THE N-CENTRAL AREA DURING THAT PERIOD. MADE A VERY
SLIGHT NWD ADJUSTMENT TO HIGHER POPS FOR THU AS WELL GIVEN
LIKELIHOOD OF FRONT STALLED NEARBY AND A POTENTIAL LOW PRESSURE WAVE
RIDING N TOWARD THE AREA. WINDS WERE LOWERED SOME ON MAINLY THE
N-S CHANNELS WED INTO THU AS PRESSURE GRADIENT ORIENTATION WILL
FAVOR THE MORE E-W CHANNELS THAN THE N-S ONES. BEYOND THU...DID
NOT MAKE ANY SIGNIFICANT CHANGES TO THE FORECAST. DUE TO THE
LARGE SCALE PATTERN BUT DETAIL UNCERTAINTIES...CONFIDENCE IN FORECAST
FOR A GENERALLY WET AND MILDER PERIOD IS FAIRLY HIGH BUT
CONFIDENCE IN TIMING ANY BREAKS IN BETWEEN SYSTEMS IS RATHER LOW.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ011>013-031-035.
         SMALL CRAFT ADVISORY FOR PKZ021-022-032>034-036-041>043-051-052.

&&

PRB/RWT