Area Forecast Discussion - Southeastern

FXAK67 PAJK 170100
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
400 PM AKST SAT FEB 16 2013
.SHORT TERM...A FRONT HAS PASSED INTO CANADA AND THE LOW LEVEL
PARTLY CLOUDY CONDITIONS IN THE POST FRONTAL AIRMASS IS QUICKLY
BEING OVERRUN BY THE HIGH LEVEL BAROCLINIC LEAF OF THE NEXT FRONT
HEADED OUR WAY. THE LOW ITSELF IS LOCATED OVER THE WESTERN END OF
THE ALASKAN PENINSULA AND WILL TRACK NORTHWEST ALONG THE SOUTHERN
COAST THROUGH SUNDAY MORNING. THE LOW WILL BE FULLY OCCLUDED BY
SUNDAY MORNING, SO THERE WILL NOT BE MUCH OF A WARM SECTOR LEFT
BY THE TIME THE FRONT MAKES IT TO THE OUTER COAST TOMORROW. IN
THE MEAN TIMES, WEAK LOW LEVEL COLD AIR ADVECTION WILL PRODUCE
OVERNIGHT LOWS A FEW DEGREES COLDER TONIGHT THAN IN THE PAST FEW
DAYS. AM EXPECTING LOWS DOWN TO OR SLIGHTLY BELOW FREEZING FOR
LOCATIONS NORTH OF FREDERICK SOUND ON THE INSIDE AND NORTH OF
CAPE EDGECUMBE ON THE OUTSIDE AS WELL AS NEAR HYDER. RESIDUAL
SHOWER ACTIVITY WILL BE PUSHED UP AGAINST THE COAST MOUNTAINS
TONIGHT, SO IT WILL BE A WHILE BEFORE RAIN SHOWERS CHANGE OVER TO
SNOW SHOWERS. FRONTAL PRECIP WILL APPROACH THE OUTER COAST LATE
TONIGHT AND SPREAD INLAND THROUGH THE DAY SUNDAY. BEST CHANCE FOR
SNOW WILL BE IN THE MORNING OVER THE NORTHERN THIRD OF THE
PANHANDLE BEFORE TEMPS RISE AND THE SNOW LEVEL MIGRATES NORTH OF
THE ICY STRAIT CORRIDOR. TOTAL SNOW OUT OF THIS FRONT SHOULD BE
2 TO 2 1/2 INCHES OR LESS. 

WEST TO SOUTHWEST LOW LEVEL ONSHORE WINDS ALONG THE OUTER COAST
RESULTING FROM A SURFACE RIDGE MOVING OVER THE AREA WILL BACK TO
THE SOUTHEAST TONIGHT OVER THE COASTAL MARINE ZONES AND INCREASE
TO 30 KTS OVER THE SOUTHERN HALF AND 35 KTS NORTH OF CAPE SPENCER
THROUGH TOMORROW AFTERNOON. TYPICAL OFFSHORE RESPONSES OVER THE
INNER CHANNELS. LOW PRESSURE OVER THE YUKON THIS AFTERNOON IS
INTERACTING WITH THE SURFACE RIDGE MOVING EAST AND PRODUCING
SOUTHERLY GALES OVER NORTHERN LYNN CANAL THIS AFTERNOON. LOOK FOR
THOSE WINDS TO DIMINISH OVERNIGHT AS THE RIDGE CONTINUES MOVING
OFF TO THE EAST AND THE SOUTHERLY PRESSURE GRADIENT RELAXES.

BLENDED GEM, ECMWF, AND NAM FOR PRESSURE AND WIND. USED A
COMBINATION OF ECMWF AND GEM BLENDED TO OFFICIAL FOR POP AND QPF.
TEMPS AND SNOW LEVELS ADJUSTED USING NAM, SREF, AND GFS. FORECAST
CONFIDENCE IS ABOVE AVERAGE.
.LONG TERM...LITTLE CHANGE TO THE FORECAST INCLUDING THE WARMER
THAN SEASONAL CONDITIONS ALL THE WAY THROUGH DAY 7. THREE MATURING
OCCLUSIONS WILL BE MOVING NE THROUGH THE GULF AND INTO THE
PANHANDLE FROM NOW THROUGH DAY SEVEN, AND ON THE LARGE SCALE 
HAVE THE TYPICAL ZONAL TRACK ACROSS THE N PACIFIC TURNING NE
IN TO THE GULF. ON SMALLER SCALES THE MODEL SOLUTIONS SPREADS 
ARE IMPORTANT. THE LARGE SCALE PATTERN IS PROGRESSIVE.

THE NEXT OCCLUDING FRONTAL SYSTEM THAT WILL REACH OUR AREA OF
RESPONSIBILITY HAS A PARENT LOW OF ABOUT 993 MB 60 NM SW OF
DUTCH HARBOR WITH THE ASSOCIATED OCCLUSION EXTENDING E FROM
BRISTOL BAY TO A TRIPLE POINT ROUGHLY 120 NM S OF KODIAK.  THIS
GALE FORCE SYSTEM IS TRACKING TO THE ENE TOWARD OUR AREA OF
RESPONSIBILITY. NOTE THE HEADLINES FOR GALES FOR MARINE ZONES 
51 AND 52, AND THAT GALE FORCE WINDS WILL FOLLOW IN MARINE ZONE
43 SUN NIGHT. 

HURRICANE FORCE SYSTEM IN THE WESTERN PACIFIC IS EXTRA TROPICAL.
IT HAS A RECENT HISTORY IN THE TROPICS...AND AS SUCH CAN BE TOUGH
FOR THE MODELS. FOR 00Z WED THE ECMWF AND GFS THE SOLUTIONS SPREAD
OUT FOR THE LOW(S) WITHIN 200 NM OF KODIAK...AND ARE ALSO CASTING
ABOUT FROM RUN TO RUN. SUCH PROBLEMS ARE STRONGLY ASSOCIATED WITH
THE WEST PACIFIC SYSTEM. THESE ISSUES RESULT IN LOWERED CONFIDENCE
FOR THE LONG RANGE FORECAST PACKAGE.

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ012-051-052. 
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>036-041>043. 

&&

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FRITSCH/JBT