Wind Advisory 89, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
541 AM AKST SAT DEC 4 2010

.SHORT TERM...OCCLUDED FRONT OVER THE CENTRAL GULF WILL DRIFT TO
THE E-CNTRL GULF BY THIS EVENING...THEN STALL BEFORE STARTING TO
DRIFT WWD LATE TONIGHT. HIGH PRESSURE WILL REMAIN OVER BC THRU
TONIGHT. USED A BLEND OF THE 00Z ECMWF AND 06Z NAM FOR TODAY AND
TONIGHT AS THEY FIT THE SATELLITE DATA AND OBS THE BEST.

 THE MAIN FORECAST ISSUES WILL BE PTYPE AND WINDS. TEMPS OVER THE
INNER CHANNELS ARE WARMING UP FAIRLY FAST THIS MORNING...FASTER
THAN EXPECTED...AND THIS WILL LIMIT SNOW POTENTIAL SOMEWHAT. IT
IS HIGHLY UNLIKELY THAT THE PAJN-PAEL CORRIDOR WILL GET ADVY
LEVEL SNOWFALL DUE TO THIS FAST WARMING SO ALL THOSE ADVYS WERE
CANCELLED WITH THE NEW PACKAGE. THE PAYA AREA CHANGED TO RAIN
ALREADY SO THEIR WARNING WAS CANCELLED. THE PAHN AND PAGY AREAS
HAVE WARMED UP IN THE LOWER LEVELS...BUT WHITE PASS AND FURTHER
NW ALONG THE HAINES HIGHWAY ARE STILL PLENTY COLD FOR ALL SNOW.
HAVE KEPT THE WARNINGS FOR THE PAHN AND PAGY ZONES BUT EMPHASIZED
HEAVIEST AMOUNTS AT HIGHER ELEVATIONS. CONFIDENCE IN SNOW AMOUNTS
ANYWHERE ARE NOT VERY HIGH HOWEVER.

 AS FOR THE WIND...FAIRLY STRONG SLY WINDS IN LYNN CANAL AND PAGY
AREAS ATTM. WOULD NORMALLY ISSUE A WIND ADVY FOR THE PAHN AND
PAGY AREAS IN THIS SITUATION BUT WITH THE WSW OUT...THE WIND
HAZARD WAS MENTIONED IN THE WSW STATEMENT. FURTHER S...WHILE PRES
GRADIENTS MIGHT SUGGEST WIND ADVY FOR THE CENTRAL AREA TO THE
COAST...LOW LEVEL STABLE LAYER WILL TEND TO KEEP ADVY LEVEL WINDS
ABOVE THE SFC. DID USE BREEZY FOR MUCH OF THE CENTRAL AREA TO THE
COAST FOR TODAY. THESE WINDS SHOULD DECREASE TONIGHT AS THE FRONT
STARTS TO MOVE BACK TO THE W AND PRES GRADIENTS WEAKEN.

 OTHERWISE...TEMPS MOST AREAS WILL LIKELY REMAIN STEADY OR RISE A
FEW DEGREES OVERNIGHT TONIGHT WITH THE WARMER AIR MOVING IN. THE
FAR SERN AREA HAS BEST CHANCE TO COOL OFF A BIT TONIGHT DUE TO
WINDS DROPPING OFF AND SOME CLEARING POSSIBLE ESPECIALLY LATE
TONIGHT. ALL IN ALL...NOT THE HIGHEST CONFIDENCE FORECAST GOING
OUT TODAY.

 &&

 .LONG TERM...EXTENDED FORECAST STARTS OUT WITH THE FRONT,
DESCRIBED ABOVE, RETREATING TO THE WEST AS A GALE FORCE LOW FORMS
IN THE NORTHERN PACIFIC AND A HIGH FORMS IN CANADA. THE PRECIP
AND WIND WILL RETREAT ALONG WITH IT. LINGERING SNOW WILL STILL BE
FALLING AROUND WHITE PASS AND THE UPPER PARTS OF THE HAINES
HIGHWAY SUNDAY MORNING BUT SHOULD DISSIPATE BY SUNDAY EVENING. 0Z
GFS WAS A BIT OF AN OUTLIER AS IT WAS A BIT TOO FAST WITH THE
RETREAT OF THE FRONT. NAM, EC, AND THE UK ALL AGREED WITH EACH
OTHER MUCH BETTER BUT THE BETTER INITIALIZATION OF THE NAM AND EC
CEMENTED THEIR USE FOR FORECAST UPDATES IN THE MID RANGE.

 AFTER THE RETREAT OF THE FRONT SE TO EAST WINDS WILL DOMINATE
THE WEATHER PICTURE FOR THE NEXT FEW DAYS AS A UPPER TROUGH
SETTLES OVER THE GULF AND THE LOW IN THE NORTH PACIFIC SITS AND
SPINS INTO LATE WEEK. BY TUESDAY THE FIRST OF SEVERAL WEAK
FRONTAL BANDS MOVE IN FROM THE SOUTH BRINGING WITH IT OUR NEXT
CHANCE OF PRECIP. PRECIP TYPE LOOKS TO BE RAIN FOR THE SOUTHERN
HALF OF THE AREA WITH A MIX TO SNOW FARTHER NORTH AS 850 MB TEMPS
ARE HOVERING AROUND -5 C. INTO NEXT WEEKEND MORE TROUGHS MOVE
INTO THE AREA EACH ONE SEEMS TO CAUSE THE FLOW OVER THE AREA TO
BECOME MORE EASTERLY AS THE WEEK GOES ON ALLOWING MORE AND MORE
COLD AIR TO SEEP INTO THE AREA FROM CANADA. BY NEXT WEEKEND MORE
OF THE PRECIP WILL BE FALLING AS SNOW AS COLDER AIR HAS HAD A
CHANCE TO FILTER IN.

 WINDS WILL ALSO PLAY A PART IN THE FORECAST. WITH THE LOW IN THE
NORTHERN PACIFIC AND THE HIGH IN THE INTERIOR OF CANADA, THAT
WILL MAINTAIN A NORTHEASTERLY GRADIENT OVER THE AREA INTO THE
WEEKEND. THE TYPICAL OUTFLOW AREAS WILL SEE SOME HIGHER WINDS AS
WINDS FLOW OUT OF INTERIOR BAYS AND PASSES PARTICULARLY AROUND
MID WEEK AS ONE OF THE STRONGER TROUGHS ROTATES BY IN THE GULF.

 MODEL AGREEMENT WAS GOOD THROUGH MOST OF THE LONG TERM PERIOD
WITH MOST MAJOR FEATURES WELL REPRESENTED. STILL SOME DIFFERENCES
ON HOW MANY LOWS WILL BE ROTATING AROUND EACH OTHER IN THE
NORTHERN PACIFIC AND WHERE EXACTLY THEY WILL BE. DECIDED TO STICK
WITH THE EC/HPC FOR EXTENDED UPDATES AS THEY HAD THE BEST
AGREEMENT WITH THE VARIOUS ENSEMBLES THAT FAR OUT. FORECAST
CONFIDENCE IS GOOD WITH LARGE SCALE FEATURES AND POOR FOR THE
MESOSCALE FEATURES.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER STORM WARNING UNTIL 9 AM AKST SUNDAY FOR AKZ018-019.
MARINE...GALE WARNING FOR PKZ012-022-042-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ011-013-021-031>036-041.

&&

RWT/EAL