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000
FXAK67 PAJK 221540
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
640 AM AKST MON DEC 22 2014

.SHORT TERM...PRESSURE HAS BEEN RISING STEADILY OVERNIGHT AFTER A
TROUGH PASSED TO THE EAST INTO CANADA AND A BROAD RIDGE OF HIGH
PRESSURE HAS FORMED OVER THE INNER CHANNELS. THIS HAS CAUSED SOUTHERLY
WINDS TO INCREASE THROUGH THE INSIDE WATERS WITH NORTHERN LYNN
CANAL REACHING SMALL CRAFT LEVEL. SW ONSHORE FLOW ACROSS THE GULF
CAN BE SEEN ON THE VAD WIND PROFILE FROM THE RADAR EXTENDING ALOFT
AT ALL LEVELS.

SHOWERS ACROSS THE AREA THIS MORNING ARE ASSOC WITH A TROUGH
EXTENDING FROM A LOW NEAR PRINCE WILLIAM SOUND AND A BAND OF UPPER
LEVEL VORTICITY. THIS WILL SHIFT NORTH THROUGH THE DAY AND ALLOW
FOR SHOWERS TO BECOME MORE SCATTERED OR ISOLATED WITH BREAKS IN
THE CLOUDS. LOOKING AT THE LATEST SATELLITE IMAGERY...THE
SOUTHERN OUTER COAST WILL PROBABLY HAVE A GOOD AMOUNT OF SUNSHINE
THIS MORNING. THIS WONT LAST TOO LONG HOWEVER AS THE NEXT SYSTEM
TO AFFECT THE AREA CAN ALSO BE SEEN ON THE SATELLITE APPROACHING
FROM THE SOUTH.

THE APPROACHING GALE FORCE LOW SOUTH WILL BRING RAIN TO THE
SOUTHERN PANHANDLE LATE TONIGHT. EXPECT PORTIONS OF POW ISLAND SEE
GUSTS OF 40MPH LATE TONIGHT AND INCREASING GUSTS OUT OF INTERIOR
PASSES AS WELL. FLOW WILL BECOME OFFSHORE ON THE NORTH SIDE OF THE
LOW AND CAUSE SHOWERS AND CLOUDS TO DIMINISH. SURFACE WINDS WILL
FLIP BACK TO THE NORTH THIS EVENING THROUGH THE INNER CHANNELS AND
INCREASE AS THE LOW DRAWS NEAR.

AS EXPECTED...TEMPERATURES SPIKED UP WITH THE WIND SHIFT TO THE
SOUTH IN SKAGWAY...JUMPING UP TO 41F EARLY THIS MORNING. THE
HAINES AIRPORT IS STILL REPORTING A NW WIND DIRECTION...BUT
SHOWERS OVERNIGHT HAVE MOSTLY BEEN LIQUID AND DOWNTOWN HAINES MOST
CERTAINLY HAS A SOUTH WIND NOW AND A BIT WARMER. THESE SOUTHERLY
WINDS WILL KEEP TEMPERATURES MILD AS WILL THE SUNNY
BREAKS...HOWEVER TEMPERATURES ALOFT ARE COOLING SOME AND THE
AMOUNT OF DAYLIGHT IS SHORT. SO NOT EXPECTING TEMPS TO WARM MUCH
DURING THE DAY. GOING INTO TONIGHT IS ANOTHER STORY. 850MB
TEMPERATURES DROP TO ABOUT -6C OVER THE NORTHERN PANHANDLE AS
SURFACE WINDS SHIFT BACK TO THE NORTH. SHOWERS WILL BE DIMINISHING
WITH INCREASING OFFSHORE FLOW...BUT SOME OF THE SCATTERED SHOWERS
COULD HAVE SNOW MIXED IN THE EVENING. AFTER THAT THE DECREASING CLOUDS
OVERNIGHT WILL MAKE FOR A COLDER MORNING ON TUESDAY.

DID NOT MAKE MANY CHANGES TO THE INHERITED FORECAST...MAINLY FOR
LOCAL EFFECTS. THE NAM INITIALIZED WELL AND WAS CLOSE TO THE GOING
FORECAST SO THAT WAS BLENDED INTO SOME FIELDS. FORECAST CONFIDENCE
IS ABOVE AVERAGE.

.LONG TERM...MOST ADJUSTMENTS TO THE FORECAST WERE MADE FOR THE
TUE AND TUE NIGHT PERIODS. WHILE THE FORECAST STILL LOOKED GOOD AS
FAR AS LOW TRACK ACROSS THE SRN AREA TUE...MODELS WERE SUGGESTING
PRECIP WOULD GET A LITTLE FURTHER N THAN PREVIOUSLY THOUGHT.
RAISED POPS ALONG THE CENTRAL PANHANDLE AROUND FREDERICK SOUND AND
ADJACENT OUTER COAST FOR TUE. SLOWED THE DEPARTURE OF THE PRECIP
TO THE SE TUE NIGHT SOME. WINDS AND TEMPS LOOKED GOOD FOR THE MOST
PART...ALTHOUGH MAX TEMPS AROUND PAYA WERE BOOSTED A BIT FOR TUE
WITH OFFSHORE FLOW AND PLENTY OF SUNSHINE EXPECTED. WILL BE
BORDERLINE FOR WIND HEADLINES OVER THE SRN AREA DUE TO GRADIENT
ORIENTATION...BUT IF LOW TRACKS ONLY A LITTLE TO THE N OF CURRENT
FORECAST...MORE WIND WILL HIT THE SRN AREA TUE INTO TUE EVENING.

STILL A TRICKY FORECAST FOR WED-THU. MODELS SEEM TO BE COMING
CLOSER TOGETHER ON SHORTWAVE ENERGY RIDING THRU RIDGE TOP AND INTO
SE AK DURING WED NIGHT AND THU. THE TEMPS REMAIN SOMEWHAT TRICKY
THOUGH AS THEY WILL DEPEND ON HOW MUCH COLDER AIR CAN MOVE INTO
THE AREA FROM THE N TUE NIGHT AND WED. IF THE COLDER AIR CAN
BECOME ESTABLISHED BEFORE PRECIP WITH SHORTWAVE MOVES IN...WILL
SEE MAINLY SNOW OVER THE NRN AND FAR ERN AREAS. THE NAM SHOWS THE
MOST COLD AIR COMING IN...AND HAS BEEN CONSISTENT ON THIS THE PAST
FEW RUNS. THE ECMWF HAS THE LEAST COLD AIR...WITH GFS AND GEM IN
THE MIDDLE. DECIDED TO LEAVE TEMPS AS IS FOR WED-THU BUT LATER
SHIFTS MIGHT NEED TO LOWER SOME TEMPS...MAINLY OVER THE N...WED
INTO THU. LOOKING LIKE AN INCREASING CHANCE FOR A WHITE CHRISTMAS
FOR THE NRN AREAS THAT DO NOT HAVE SNOW ON THE GROUND ATTM.

FOR LATE WEEK INTO EARLY NEXT WEEK...UPPER RIDGE SHOULD BUILD OVER
THE GENERAL AREA...BUT SOME MODEL DIFFERENCES ON EXACTLY WHERE IT
BUILDS REMAIN...AND THESE ARE BIG AS FAR AS BOTH PRECIP POTENTIAL
AND PTYPE ARE CONCERNED. DECIDED TO NOT CHANGE THIS PERIOD AS IT
WAS BASED ON LATEST WPC...WHICH LOOKS OK AT THIS POINT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND LATE TONIGHT FOR AKZ027.
MARINE...GALE WARNING FOR PKZ036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 221540
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
640 AM AKST MON DEC 22 2014

.SHORT TERM...PRESSURE HAS BEEN RISING STEADILY OVERNIGHT AFTER A
TROUGH PASSED TO THE EAST INTO CANADA AND A BROAD RIDGE OF HIGH
PRESSURE HAS FORMED OVER THE INNER CHANNELS. THIS HAS CAUSED SOUTHERLY
WINDS TO INCREASE THROUGH THE INSIDE WATERS WITH NORTHERN LYNN
CANAL REACHING SMALL CRAFT LEVEL. SW ONSHORE FLOW ACROSS THE GULF
CAN BE SEEN ON THE VAD WIND PROFILE FROM THE RADAR EXTENDING ALOFT
AT ALL LEVELS.

SHOWERS ACROSS THE AREA THIS MORNING ARE ASSOC WITH A TROUGH
EXTENDING FROM A LOW NEAR PRINCE WILLIAM SOUND AND A BAND OF UPPER
LEVEL VORTICITY. THIS WILL SHIFT NORTH THROUGH THE DAY AND ALLOW
FOR SHOWERS TO BECOME MORE SCATTERED OR ISOLATED WITH BREAKS IN
THE CLOUDS. LOOKING AT THE LATEST SATELLITE IMAGERY...THE
SOUTHERN OUTER COAST WILL PROBABLY HAVE A GOOD AMOUNT OF SUNSHINE
THIS MORNING. THIS WONT LAST TOO LONG HOWEVER AS THE NEXT SYSTEM
TO AFFECT THE AREA CAN ALSO BE SEEN ON THE SATELLITE APPROACHING
FROM THE SOUTH.

THE APPROACHING GALE FORCE LOW SOUTH WILL BRING RAIN TO THE
SOUTHERN PANHANDLE LATE TONIGHT. EXPECT PORTIONS OF POW ISLAND SEE
GUSTS OF 40MPH LATE TONIGHT AND INCREASING GUSTS OUT OF INTERIOR
PASSES AS WELL. FLOW WILL BECOME OFFSHORE ON THE NORTH SIDE OF THE
LOW AND CAUSE SHOWERS AND CLOUDS TO DIMINISH. SURFACE WINDS WILL
FLIP BACK TO THE NORTH THIS EVENING THROUGH THE INNER CHANNELS AND
INCREASE AS THE LOW DRAWS NEAR.

AS EXPECTED...TEMPERATURES SPIKED UP WITH THE WIND SHIFT TO THE
SOUTH IN SKAGWAY...JUMPING UP TO 41F EARLY THIS MORNING. THE
HAINES AIRPORT IS STILL REPORTING A NW WIND DIRECTION...BUT
SHOWERS OVERNIGHT HAVE MOSTLY BEEN LIQUID AND DOWNTOWN HAINES MOST
CERTAINLY HAS A SOUTH WIND NOW AND A BIT WARMER. THESE SOUTHERLY
WINDS WILL KEEP TEMPERATURES MILD AS WILL THE SUNNY
BREAKS...HOWEVER TEMPERATURES ALOFT ARE COOLING SOME AND THE
AMOUNT OF DAYLIGHT IS SHORT. SO NOT EXPECTING TEMPS TO WARM MUCH
DURING THE DAY. GOING INTO TONIGHT IS ANOTHER STORY. 850MB
TEMPERATURES DROP TO ABOUT -6C OVER THE NORTHERN PANHANDLE AS
SURFACE WINDS SHIFT BACK TO THE NORTH. SHOWERS WILL BE DIMINISHING
WITH INCREASING OFFSHORE FLOW...BUT SOME OF THE SCATTERED SHOWERS
COULD HAVE SNOW MIXED IN THE EVENING. AFTER THAT THE DECREASING CLOUDS
OVERNIGHT WILL MAKE FOR A COLDER MORNING ON TUESDAY.

DID NOT MAKE MANY CHANGES TO THE INHERITED FORECAST...MAINLY FOR
LOCAL EFFECTS. THE NAM INITIALIZED WELL AND WAS CLOSE TO THE GOING
FORECAST SO THAT WAS BLENDED INTO SOME FIELDS. FORECAST CONFIDENCE
IS ABOVE AVERAGE.

.LONG TERM...MOST ADJUSTMENTS TO THE FORECAST WERE MADE FOR THE
TUE AND TUE NIGHT PERIODS. WHILE THE FORECAST STILL LOOKED GOOD AS
FAR AS LOW TRACK ACROSS THE SRN AREA TUE...MODELS WERE SUGGESTING
PRECIP WOULD GET A LITTLE FURTHER N THAN PREVIOUSLY THOUGHT.
RAISED POPS ALONG THE CENTRAL PANHANDLE AROUND FREDERICK SOUND AND
ADJACENT OUTER COAST FOR TUE. SLOWED THE DEPARTURE OF THE PRECIP
TO THE SE TUE NIGHT SOME. WINDS AND TEMPS LOOKED GOOD FOR THE MOST
PART...ALTHOUGH MAX TEMPS AROUND PAYA WERE BOOSTED A BIT FOR TUE
WITH OFFSHORE FLOW AND PLENTY OF SUNSHINE EXPECTED. WILL BE
BORDERLINE FOR WIND HEADLINES OVER THE SRN AREA DUE TO GRADIENT
ORIENTATION...BUT IF LOW TRACKS ONLY A LITTLE TO THE N OF CURRENT
FORECAST...MORE WIND WILL HIT THE SRN AREA TUE INTO TUE EVENING.

STILL A TRICKY FORECAST FOR WED-THU. MODELS SEEM TO BE COMING
CLOSER TOGETHER ON SHORTWAVE ENERGY RIDING THRU RIDGE TOP AND INTO
SE AK DURING WED NIGHT AND THU. THE TEMPS REMAIN SOMEWHAT TRICKY
THOUGH AS THEY WILL DEPEND ON HOW MUCH COLDER AIR CAN MOVE INTO
THE AREA FROM THE N TUE NIGHT AND WED. IF THE COLDER AIR CAN
BECOME ESTABLISHED BEFORE PRECIP WITH SHORTWAVE MOVES IN...WILL
SEE MAINLY SNOW OVER THE NRN AND FAR ERN AREAS. THE NAM SHOWS THE
MOST COLD AIR COMING IN...AND HAS BEEN CONSISTENT ON THIS THE PAST
FEW RUNS. THE ECMWF HAS THE LEAST COLD AIR...WITH GFS AND GEM IN
THE MIDDLE. DECIDED TO LEAVE TEMPS AS IS FOR WED-THU BUT LATER
SHIFTS MIGHT NEED TO LOWER SOME TEMPS...MAINLY OVER THE N...WED
INTO THU. LOOKING LIKE AN INCREASING CHANCE FOR A WHITE CHRISTMAS
FOR THE NRN AREAS THAT DO NOT HAVE SNOW ON THE GROUND ATTM.

FOR LATE WEEK INTO EARLY NEXT WEEK...UPPER RIDGE SHOULD BUILD OVER
THE GENERAL AREA...BUT SOME MODEL DIFFERENCES ON EXACTLY WHERE IT
BUILDS REMAIN...AND THESE ARE BIG AS FAR AS BOTH PRECIP POTENTIAL
AND PTYPE ARE CONCERNED. DECIDED TO NOT CHANGE THIS PERIOD AS IT
WAS BASED ON LATEST WPC...WHICH LOOKS OK AT THIS POINT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND LATE TONIGHT FOR AKZ027.
MARINE...GALE WARNING FOR PKZ036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 221540
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
640 AM AKST MON DEC 22 2014

.SHORT TERM...PRESSURE HAS BEEN RISING STEADILY OVERNIGHT AFTER A
TROUGH PASSED TO THE EAST INTO CANADA AND A BROAD RIDGE OF HIGH
PRESSURE HAS FORMED OVER THE INNER CHANNELS. THIS HAS CAUSED SOUTHERLY
WINDS TO INCREASE THROUGH THE INSIDE WATERS WITH NORTHERN LYNN
CANAL REACHING SMALL CRAFT LEVEL. SW ONSHORE FLOW ACROSS THE GULF
CAN BE SEEN ON THE VAD WIND PROFILE FROM THE RADAR EXTENDING ALOFT
AT ALL LEVELS.

SHOWERS ACROSS THE AREA THIS MORNING ARE ASSOC WITH A TROUGH
EXTENDING FROM A LOW NEAR PRINCE WILLIAM SOUND AND A BAND OF UPPER
LEVEL VORTICITY. THIS WILL SHIFT NORTH THROUGH THE DAY AND ALLOW
FOR SHOWERS TO BECOME MORE SCATTERED OR ISOLATED WITH BREAKS IN
THE CLOUDS. LOOKING AT THE LATEST SATELLITE IMAGERY...THE
SOUTHERN OUTER COAST WILL PROBABLY HAVE A GOOD AMOUNT OF SUNSHINE
THIS MORNING. THIS WONT LAST TOO LONG HOWEVER AS THE NEXT SYSTEM
TO AFFECT THE AREA CAN ALSO BE SEEN ON THE SATELLITE APPROACHING
FROM THE SOUTH.

THE APPROACHING GALE FORCE LOW SOUTH WILL BRING RAIN TO THE
SOUTHERN PANHANDLE LATE TONIGHT. EXPECT PORTIONS OF POW ISLAND SEE
GUSTS OF 40MPH LATE TONIGHT AND INCREASING GUSTS OUT OF INTERIOR
PASSES AS WELL. FLOW WILL BECOME OFFSHORE ON THE NORTH SIDE OF THE
LOW AND CAUSE SHOWERS AND CLOUDS TO DIMINISH. SURFACE WINDS WILL
FLIP BACK TO THE NORTH THIS EVENING THROUGH THE INNER CHANNELS AND
INCREASE AS THE LOW DRAWS NEAR.

AS EXPECTED...TEMPERATURES SPIKED UP WITH THE WIND SHIFT TO THE
SOUTH IN SKAGWAY...JUMPING UP TO 41F EARLY THIS MORNING. THE
HAINES AIRPORT IS STILL REPORTING A NW WIND DIRECTION...BUT
SHOWERS OVERNIGHT HAVE MOSTLY BEEN LIQUID AND DOWNTOWN HAINES MOST
CERTAINLY HAS A SOUTH WIND NOW AND A BIT WARMER. THESE SOUTHERLY
WINDS WILL KEEP TEMPERATURES MILD AS WILL THE SUNNY
BREAKS...HOWEVER TEMPERATURES ALOFT ARE COOLING SOME AND THE
AMOUNT OF DAYLIGHT IS SHORT. SO NOT EXPECTING TEMPS TO WARM MUCH
DURING THE DAY. GOING INTO TONIGHT IS ANOTHER STORY. 850MB
TEMPERATURES DROP TO ABOUT -6C OVER THE NORTHERN PANHANDLE AS
SURFACE WINDS SHIFT BACK TO THE NORTH. SHOWERS WILL BE DIMINISHING
WITH INCREASING OFFSHORE FLOW...BUT SOME OF THE SCATTERED SHOWERS
COULD HAVE SNOW MIXED IN THE EVENING. AFTER THAT THE DECREASING CLOUDS
OVERNIGHT WILL MAKE FOR A COLDER MORNING ON TUESDAY.

DID NOT MAKE MANY CHANGES TO THE INHERITED FORECAST...MAINLY FOR
LOCAL EFFECTS. THE NAM INITIALIZED WELL AND WAS CLOSE TO THE GOING
FORECAST SO THAT WAS BLENDED INTO SOME FIELDS. FORECAST CONFIDENCE
IS ABOVE AVERAGE.

.LONG TERM...MOST ADJUSTMENTS TO THE FORECAST WERE MADE FOR THE
TUE AND TUE NIGHT PERIODS. WHILE THE FORECAST STILL LOOKED GOOD AS
FAR AS LOW TRACK ACROSS THE SRN AREA TUE...MODELS WERE SUGGESTING
PRECIP WOULD GET A LITTLE FURTHER N THAN PREVIOUSLY THOUGHT.
RAISED POPS ALONG THE CENTRAL PANHANDLE AROUND FREDERICK SOUND AND
ADJACENT OUTER COAST FOR TUE. SLOWED THE DEPARTURE OF THE PRECIP
TO THE SE TUE NIGHT SOME. WINDS AND TEMPS LOOKED GOOD FOR THE MOST
PART...ALTHOUGH MAX TEMPS AROUND PAYA WERE BOOSTED A BIT FOR TUE
WITH OFFSHORE FLOW AND PLENTY OF SUNSHINE EXPECTED. WILL BE
BORDERLINE FOR WIND HEADLINES OVER THE SRN AREA DUE TO GRADIENT
ORIENTATION...BUT IF LOW TRACKS ONLY A LITTLE TO THE N OF CURRENT
FORECAST...MORE WIND WILL HIT THE SRN AREA TUE INTO TUE EVENING.

STILL A TRICKY FORECAST FOR WED-THU. MODELS SEEM TO BE COMING
CLOSER TOGETHER ON SHORTWAVE ENERGY RIDING THRU RIDGE TOP AND INTO
SE AK DURING WED NIGHT AND THU. THE TEMPS REMAIN SOMEWHAT TRICKY
THOUGH AS THEY WILL DEPEND ON HOW MUCH COLDER AIR CAN MOVE INTO
THE AREA FROM THE N TUE NIGHT AND WED. IF THE COLDER AIR CAN
BECOME ESTABLISHED BEFORE PRECIP WITH SHORTWAVE MOVES IN...WILL
SEE MAINLY SNOW OVER THE NRN AND FAR ERN AREAS. THE NAM SHOWS THE
MOST COLD AIR COMING IN...AND HAS BEEN CONSISTENT ON THIS THE PAST
FEW RUNS. THE ECMWF HAS THE LEAST COLD AIR...WITH GFS AND GEM IN
THE MIDDLE. DECIDED TO LEAVE TEMPS AS IS FOR WED-THU BUT LATER
SHIFTS MIGHT NEED TO LOWER SOME TEMPS...MAINLY OVER THE N...WED
INTO THU. LOOKING LIKE AN INCREASING CHANCE FOR A WHITE CHRISTMAS
FOR THE NRN AREAS THAT DO NOT HAVE SNOW ON THE GROUND ATTM.

FOR LATE WEEK INTO EARLY NEXT WEEK...UPPER RIDGE SHOULD BUILD OVER
THE GENERAL AREA...BUT SOME MODEL DIFFERENCES ON EXACTLY WHERE IT
BUILDS REMAIN...AND THESE ARE BIG AS FAR AS BOTH PRECIP POTENTIAL
AND PTYPE ARE CONCERNED. DECIDED TO NOT CHANGE THIS PERIOD AS IT
WAS BASED ON LATEST WPC...WHICH LOOKS OK AT THIS POINT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND LATE TONIGHT FOR AKZ027.
MARINE...GALE WARNING FOR PKZ036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 221540
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
640 AM AKST MON DEC 22 2014

.SHORT TERM...PRESSURE HAS BEEN RISING STEADILY OVERNIGHT AFTER A
TROUGH PASSED TO THE EAST INTO CANADA AND A BROAD RIDGE OF HIGH
PRESSURE HAS FORMED OVER THE INNER CHANNELS. THIS HAS CAUSED SOUTHERLY
WINDS TO INCREASE THROUGH THE INSIDE WATERS WITH NORTHERN LYNN
CANAL REACHING SMALL CRAFT LEVEL. SW ONSHORE FLOW ACROSS THE GULF
CAN BE SEEN ON THE VAD WIND PROFILE FROM THE RADAR EXTENDING ALOFT
AT ALL LEVELS.

SHOWERS ACROSS THE AREA THIS MORNING ARE ASSOC WITH A TROUGH
EXTENDING FROM A LOW NEAR PRINCE WILLIAM SOUND AND A BAND OF UPPER
LEVEL VORTICITY. THIS WILL SHIFT NORTH THROUGH THE DAY AND ALLOW
FOR SHOWERS TO BECOME MORE SCATTERED OR ISOLATED WITH BREAKS IN
THE CLOUDS. LOOKING AT THE LATEST SATELLITE IMAGERY...THE
SOUTHERN OUTER COAST WILL PROBABLY HAVE A GOOD AMOUNT OF SUNSHINE
THIS MORNING. THIS WONT LAST TOO LONG HOWEVER AS THE NEXT SYSTEM
TO AFFECT THE AREA CAN ALSO BE SEEN ON THE SATELLITE APPROACHING
FROM THE SOUTH.

THE APPROACHING GALE FORCE LOW SOUTH WILL BRING RAIN TO THE
SOUTHERN PANHANDLE LATE TONIGHT. EXPECT PORTIONS OF POW ISLAND SEE
GUSTS OF 40MPH LATE TONIGHT AND INCREASING GUSTS OUT OF INTERIOR
PASSES AS WELL. FLOW WILL BECOME OFFSHORE ON THE NORTH SIDE OF THE
LOW AND CAUSE SHOWERS AND CLOUDS TO DIMINISH. SURFACE WINDS WILL
FLIP BACK TO THE NORTH THIS EVENING THROUGH THE INNER CHANNELS AND
INCREASE AS THE LOW DRAWS NEAR.

AS EXPECTED...TEMPERATURES SPIKED UP WITH THE WIND SHIFT TO THE
SOUTH IN SKAGWAY...JUMPING UP TO 41F EARLY THIS MORNING. THE
HAINES AIRPORT IS STILL REPORTING A NW WIND DIRECTION...BUT
SHOWERS OVERNIGHT HAVE MOSTLY BEEN LIQUID AND DOWNTOWN HAINES MOST
CERTAINLY HAS A SOUTH WIND NOW AND A BIT WARMER. THESE SOUTHERLY
WINDS WILL KEEP TEMPERATURES MILD AS WILL THE SUNNY
BREAKS...HOWEVER TEMPERATURES ALOFT ARE COOLING SOME AND THE
AMOUNT OF DAYLIGHT IS SHORT. SO NOT EXPECTING TEMPS TO WARM MUCH
DURING THE DAY. GOING INTO TONIGHT IS ANOTHER STORY. 850MB
TEMPERATURES DROP TO ABOUT -6C OVER THE NORTHERN PANHANDLE AS
SURFACE WINDS SHIFT BACK TO THE NORTH. SHOWERS WILL BE DIMINISHING
WITH INCREASING OFFSHORE FLOW...BUT SOME OF THE SCATTERED SHOWERS
COULD HAVE SNOW MIXED IN THE EVENING. AFTER THAT THE DECREASING CLOUDS
OVERNIGHT WILL MAKE FOR A COLDER MORNING ON TUESDAY.

DID NOT MAKE MANY CHANGES TO THE INHERITED FORECAST...MAINLY FOR
LOCAL EFFECTS. THE NAM INITIALIZED WELL AND WAS CLOSE TO THE GOING
FORECAST SO THAT WAS BLENDED INTO SOME FIELDS. FORECAST CONFIDENCE
IS ABOVE AVERAGE.

.LONG TERM...MOST ADJUSTMENTS TO THE FORECAST WERE MADE FOR THE
TUE AND TUE NIGHT PERIODS. WHILE THE FORECAST STILL LOOKED GOOD AS
FAR AS LOW TRACK ACROSS THE SRN AREA TUE...MODELS WERE SUGGESTING
PRECIP WOULD GET A LITTLE FURTHER N THAN PREVIOUSLY THOUGHT.
RAISED POPS ALONG THE CENTRAL PANHANDLE AROUND FREDERICK SOUND AND
ADJACENT OUTER COAST FOR TUE. SLOWED THE DEPARTURE OF THE PRECIP
TO THE SE TUE NIGHT SOME. WINDS AND TEMPS LOOKED GOOD FOR THE MOST
PART...ALTHOUGH MAX TEMPS AROUND PAYA WERE BOOSTED A BIT FOR TUE
WITH OFFSHORE FLOW AND PLENTY OF SUNSHINE EXPECTED. WILL BE
BORDERLINE FOR WIND HEADLINES OVER THE SRN AREA DUE TO GRADIENT
ORIENTATION...BUT IF LOW TRACKS ONLY A LITTLE TO THE N OF CURRENT
FORECAST...MORE WIND WILL HIT THE SRN AREA TUE INTO TUE EVENING.

STILL A TRICKY FORECAST FOR WED-THU. MODELS SEEM TO BE COMING
CLOSER TOGETHER ON SHORTWAVE ENERGY RIDING THRU RIDGE TOP AND INTO
SE AK DURING WED NIGHT AND THU. THE TEMPS REMAIN SOMEWHAT TRICKY
THOUGH AS THEY WILL DEPEND ON HOW MUCH COLDER AIR CAN MOVE INTO
THE AREA FROM THE N TUE NIGHT AND WED. IF THE COLDER AIR CAN
BECOME ESTABLISHED BEFORE PRECIP WITH SHORTWAVE MOVES IN...WILL
SEE MAINLY SNOW OVER THE NRN AND FAR ERN AREAS. THE NAM SHOWS THE
MOST COLD AIR COMING IN...AND HAS BEEN CONSISTENT ON THIS THE PAST
FEW RUNS. THE ECMWF HAS THE LEAST COLD AIR...WITH GFS AND GEM IN
THE MIDDLE. DECIDED TO LEAVE TEMPS AS IS FOR WED-THU BUT LATER
SHIFTS MIGHT NEED TO LOWER SOME TEMPS...MAINLY OVER THE N...WED
INTO THU. LOOKING LIKE AN INCREASING CHANCE FOR A WHITE CHRISTMAS
FOR THE NRN AREAS THAT DO NOT HAVE SNOW ON THE GROUND ATTM.

FOR LATE WEEK INTO EARLY NEXT WEEK...UPPER RIDGE SHOULD BUILD OVER
THE GENERAL AREA...BUT SOME MODEL DIFFERENCES ON EXACTLY WHERE IT
BUILDS REMAIN...AND THESE ARE BIG AS FAR AS BOTH PRECIP POTENTIAL
AND PTYPE ARE CONCERNED. DECIDED TO NOT CHANGE THIS PERIOD AS IT
WAS BASED ON LATEST WPC...WHICH LOOKS OK AT THIS POINT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND LATE TONIGHT FOR AKZ027.
MARINE...GALE WARNING FOR PKZ036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 221540
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
640 AM AKST MON DEC 22 2014

.SHORT TERM...PRESSURE HAS BEEN RISING STEADILY OVERNIGHT AFTER A
TROUGH PASSED TO THE EAST INTO CANADA AND A BROAD RIDGE OF HIGH
PRESSURE HAS FORMED OVER THE INNER CHANNELS. THIS HAS CAUSED SOUTHERLY
WINDS TO INCREASE THROUGH THE INSIDE WATERS WITH NORTHERN LYNN
CANAL REACHING SMALL CRAFT LEVEL. SW ONSHORE FLOW ACROSS THE GULF
CAN BE SEEN ON THE VAD WIND PROFILE FROM THE RADAR EXTENDING ALOFT
AT ALL LEVELS.

SHOWERS ACROSS THE AREA THIS MORNING ARE ASSOC WITH A TROUGH
EXTENDING FROM A LOW NEAR PRINCE WILLIAM SOUND AND A BAND OF UPPER
LEVEL VORTICITY. THIS WILL SHIFT NORTH THROUGH THE DAY AND ALLOW
FOR SHOWERS TO BECOME MORE SCATTERED OR ISOLATED WITH BREAKS IN
THE CLOUDS. LOOKING AT THE LATEST SATELLITE IMAGERY...THE
SOUTHERN OUTER COAST WILL PROBABLY HAVE A GOOD AMOUNT OF SUNSHINE
THIS MORNING. THIS WONT LAST TOO LONG HOWEVER AS THE NEXT SYSTEM
TO AFFECT THE AREA CAN ALSO BE SEEN ON THE SATELLITE APPROACHING
FROM THE SOUTH.

THE APPROACHING GALE FORCE LOW SOUTH WILL BRING RAIN TO THE
SOUTHERN PANHANDLE LATE TONIGHT. EXPECT PORTIONS OF POW ISLAND SEE
GUSTS OF 40MPH LATE TONIGHT AND INCREASING GUSTS OUT OF INTERIOR
PASSES AS WELL. FLOW WILL BECOME OFFSHORE ON THE NORTH SIDE OF THE
LOW AND CAUSE SHOWERS AND CLOUDS TO DIMINISH. SURFACE WINDS WILL
FLIP BACK TO THE NORTH THIS EVENING THROUGH THE INNER CHANNELS AND
INCREASE AS THE LOW DRAWS NEAR.

AS EXPECTED...TEMPERATURES SPIKED UP WITH THE WIND SHIFT TO THE
SOUTH IN SKAGWAY...JUMPING UP TO 41F EARLY THIS MORNING. THE
HAINES AIRPORT IS STILL REPORTING A NW WIND DIRECTION...BUT
SHOWERS OVERNIGHT HAVE MOSTLY BEEN LIQUID AND DOWNTOWN HAINES MOST
CERTAINLY HAS A SOUTH WIND NOW AND A BIT WARMER. THESE SOUTHERLY
WINDS WILL KEEP TEMPERATURES MILD AS WILL THE SUNNY
BREAKS...HOWEVER TEMPERATURES ALOFT ARE COOLING SOME AND THE
AMOUNT OF DAYLIGHT IS SHORT. SO NOT EXPECTING TEMPS TO WARM MUCH
DURING THE DAY. GOING INTO TONIGHT IS ANOTHER STORY. 850MB
TEMPERATURES DROP TO ABOUT -6C OVER THE NORTHERN PANHANDLE AS
SURFACE WINDS SHIFT BACK TO THE NORTH. SHOWERS WILL BE DIMINISHING
WITH INCREASING OFFSHORE FLOW...BUT SOME OF THE SCATTERED SHOWERS
COULD HAVE SNOW MIXED IN THE EVENING. AFTER THAT THE DECREASING CLOUDS
OVERNIGHT WILL MAKE FOR A COLDER MORNING ON TUESDAY.

DID NOT MAKE MANY CHANGES TO THE INHERITED FORECAST...MAINLY FOR
LOCAL EFFECTS. THE NAM INITIALIZED WELL AND WAS CLOSE TO THE GOING
FORECAST SO THAT WAS BLENDED INTO SOME FIELDS. FORECAST CONFIDENCE
IS ABOVE AVERAGE.

.LONG TERM...MOST ADJUSTMENTS TO THE FORECAST WERE MADE FOR THE
TUE AND TUE NIGHT PERIODS. WHILE THE FORECAST STILL LOOKED GOOD AS
FAR AS LOW TRACK ACROSS THE SRN AREA TUE...MODELS WERE SUGGESTING
PRECIP WOULD GET A LITTLE FURTHER N THAN PREVIOUSLY THOUGHT.
RAISED POPS ALONG THE CENTRAL PANHANDLE AROUND FREDERICK SOUND AND
ADJACENT OUTER COAST FOR TUE. SLOWED THE DEPARTURE OF THE PRECIP
TO THE SE TUE NIGHT SOME. WINDS AND TEMPS LOOKED GOOD FOR THE MOST
PART...ALTHOUGH MAX TEMPS AROUND PAYA WERE BOOSTED A BIT FOR TUE
WITH OFFSHORE FLOW AND PLENTY OF SUNSHINE EXPECTED. WILL BE
BORDERLINE FOR WIND HEADLINES OVER THE SRN AREA DUE TO GRADIENT
ORIENTATION...BUT IF LOW TRACKS ONLY A LITTLE TO THE N OF CURRENT
FORECAST...MORE WIND WILL HIT THE SRN AREA TUE INTO TUE EVENING.

STILL A TRICKY FORECAST FOR WED-THU. MODELS SEEM TO BE COMING
CLOSER TOGETHER ON SHORTWAVE ENERGY RIDING THRU RIDGE TOP AND INTO
SE AK DURING WED NIGHT AND THU. THE TEMPS REMAIN SOMEWHAT TRICKY
THOUGH AS THEY WILL DEPEND ON HOW MUCH COLDER AIR CAN MOVE INTO
THE AREA FROM THE N TUE NIGHT AND WED. IF THE COLDER AIR CAN
BECOME ESTABLISHED BEFORE PRECIP WITH SHORTWAVE MOVES IN...WILL
SEE MAINLY SNOW OVER THE NRN AND FAR ERN AREAS. THE NAM SHOWS THE
MOST COLD AIR COMING IN...AND HAS BEEN CONSISTENT ON THIS THE PAST
FEW RUNS. THE ECMWF HAS THE LEAST COLD AIR...WITH GFS AND GEM IN
THE MIDDLE. DECIDED TO LEAVE TEMPS AS IS FOR WED-THU BUT LATER
SHIFTS MIGHT NEED TO LOWER SOME TEMPS...MAINLY OVER THE N...WED
INTO THU. LOOKING LIKE AN INCREASING CHANCE FOR A WHITE CHRISTMAS
FOR THE NRN AREAS THAT DO NOT HAVE SNOW ON THE GROUND ATTM.

FOR LATE WEEK INTO EARLY NEXT WEEK...UPPER RIDGE SHOULD BUILD OVER
THE GENERAL AREA...BUT SOME MODEL DIFFERENCES ON EXACTLY WHERE IT
BUILDS REMAIN...AND THESE ARE BIG AS FAR AS BOTH PRECIP POTENTIAL
AND PTYPE ARE CONCERNED. DECIDED TO NOT CHANGE THIS PERIOD AS IT
WAS BASED ON LATEST WPC...WHICH LOOKS OK AT THIS POINT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND LATE TONIGHT FOR AKZ027.
MARINE...GALE WARNING FOR PKZ036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK67 PAJK 221540
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
640 AM AKST MON DEC 22 2014

.SHORT TERM...PRESSURE HAS BEEN RISING STEADILY OVERNIGHT AFTER A
TROUGH PASSED TO THE EAST INTO CANADA AND A BROAD RIDGE OF HIGH
PRESSURE HAS FORMED OVER THE INNER CHANNELS. THIS HAS CAUSED SOUTHERLY
WINDS TO INCREASE THROUGH THE INSIDE WATERS WITH NORTHERN LYNN
CANAL REACHING SMALL CRAFT LEVEL. SW ONSHORE FLOW ACROSS THE GULF
CAN BE SEEN ON THE VAD WIND PROFILE FROM THE RADAR EXTENDING ALOFT
AT ALL LEVELS.

SHOWERS ACROSS THE AREA THIS MORNING ARE ASSOC WITH A TROUGH
EXTENDING FROM A LOW NEAR PRINCE WILLIAM SOUND AND A BAND OF UPPER
LEVEL VORTICITY. THIS WILL SHIFT NORTH THROUGH THE DAY AND ALLOW
FOR SHOWERS TO BECOME MORE SCATTERED OR ISOLATED WITH BREAKS IN
THE CLOUDS. LOOKING AT THE LATEST SATELLITE IMAGERY...THE
SOUTHERN OUTER COAST WILL PROBABLY HAVE A GOOD AMOUNT OF SUNSHINE
THIS MORNING. THIS WONT LAST TOO LONG HOWEVER AS THE NEXT SYSTEM
TO AFFECT THE AREA CAN ALSO BE SEEN ON THE SATELLITE APPROACHING
FROM THE SOUTH.

THE APPROACHING GALE FORCE LOW SOUTH WILL BRING RAIN TO THE
SOUTHERN PANHANDLE LATE TONIGHT. EXPECT PORTIONS OF POW ISLAND SEE
GUSTS OF 40MPH LATE TONIGHT AND INCREASING GUSTS OUT OF INTERIOR
PASSES AS WELL. FLOW WILL BECOME OFFSHORE ON THE NORTH SIDE OF THE
LOW AND CAUSE SHOWERS AND CLOUDS TO DIMINISH. SURFACE WINDS WILL
FLIP BACK TO THE NORTH THIS EVENING THROUGH THE INNER CHANNELS AND
INCREASE AS THE LOW DRAWS NEAR.

AS EXPECTED...TEMPERATURES SPIKED UP WITH THE WIND SHIFT TO THE
SOUTH IN SKAGWAY...JUMPING UP TO 41F EARLY THIS MORNING. THE
HAINES AIRPORT IS STILL REPORTING A NW WIND DIRECTION...BUT
SHOWERS OVERNIGHT HAVE MOSTLY BEEN LIQUID AND DOWNTOWN HAINES MOST
CERTAINLY HAS A SOUTH WIND NOW AND A BIT WARMER. THESE SOUTHERLY
WINDS WILL KEEP TEMPERATURES MILD AS WILL THE SUNNY
BREAKS...HOWEVER TEMPERATURES ALOFT ARE COOLING SOME AND THE
AMOUNT OF DAYLIGHT IS SHORT. SO NOT EXPECTING TEMPS TO WARM MUCH
DURING THE DAY. GOING INTO TONIGHT IS ANOTHER STORY. 850MB
TEMPERATURES DROP TO ABOUT -6C OVER THE NORTHERN PANHANDLE AS
SURFACE WINDS SHIFT BACK TO THE NORTH. SHOWERS WILL BE DIMINISHING
WITH INCREASING OFFSHORE FLOW...BUT SOME OF THE SCATTERED SHOWERS
COULD HAVE SNOW MIXED IN THE EVENING. AFTER THAT THE DECREASING CLOUDS
OVERNIGHT WILL MAKE FOR A COLDER MORNING ON TUESDAY.

DID NOT MAKE MANY CHANGES TO THE INHERITED FORECAST...MAINLY FOR
LOCAL EFFECTS. THE NAM INITIALIZED WELL AND WAS CLOSE TO THE GOING
FORECAST SO THAT WAS BLENDED INTO SOME FIELDS. FORECAST CONFIDENCE
IS ABOVE AVERAGE.

.LONG TERM...MOST ADJUSTMENTS TO THE FORECAST WERE MADE FOR THE
TUE AND TUE NIGHT PERIODS. WHILE THE FORECAST STILL LOOKED GOOD AS
FAR AS LOW TRACK ACROSS THE SRN AREA TUE...MODELS WERE SUGGESTING
PRECIP WOULD GET A LITTLE FURTHER N THAN PREVIOUSLY THOUGHT.
RAISED POPS ALONG THE CENTRAL PANHANDLE AROUND FREDERICK SOUND AND
ADJACENT OUTER COAST FOR TUE. SLOWED THE DEPARTURE OF THE PRECIP
TO THE SE TUE NIGHT SOME. WINDS AND TEMPS LOOKED GOOD FOR THE MOST
PART...ALTHOUGH MAX TEMPS AROUND PAYA WERE BOOSTED A BIT FOR TUE
WITH OFFSHORE FLOW AND PLENTY OF SUNSHINE EXPECTED. WILL BE
BORDERLINE FOR WIND HEADLINES OVER THE SRN AREA DUE TO GRADIENT
ORIENTATION...BUT IF LOW TRACKS ONLY A LITTLE TO THE N OF CURRENT
FORECAST...MORE WIND WILL HIT THE SRN AREA TUE INTO TUE EVENING.

STILL A TRICKY FORECAST FOR WED-THU. MODELS SEEM TO BE COMING
CLOSER TOGETHER ON SHORTWAVE ENERGY RIDING THRU RIDGE TOP AND INTO
SE AK DURING WED NIGHT AND THU. THE TEMPS REMAIN SOMEWHAT TRICKY
THOUGH AS THEY WILL DEPEND ON HOW MUCH COLDER AIR CAN MOVE INTO
THE AREA FROM THE N TUE NIGHT AND WED. IF THE COLDER AIR CAN
BECOME ESTABLISHED BEFORE PRECIP WITH SHORTWAVE MOVES IN...WILL
SEE MAINLY SNOW OVER THE NRN AND FAR ERN AREAS. THE NAM SHOWS THE
MOST COLD AIR COMING IN...AND HAS BEEN CONSISTENT ON THIS THE PAST
FEW RUNS. THE ECMWF HAS THE LEAST COLD AIR...WITH GFS AND GEM IN
THE MIDDLE. DECIDED TO LEAVE TEMPS AS IS FOR WED-THU BUT LATER
SHIFTS MIGHT NEED TO LOWER SOME TEMPS...MAINLY OVER THE N...WED
INTO THU. LOOKING LIKE AN INCREASING CHANCE FOR A WHITE CHRISTMAS
FOR THE NRN AREAS THAT DO NOT HAVE SNOW ON THE GROUND ATTM.

FOR LATE WEEK INTO EARLY NEXT WEEK...UPPER RIDGE SHOULD BUILD OVER
THE GENERAL AREA...BUT SOME MODEL DIFFERENCES ON EXACTLY WHERE IT
BUILDS REMAIN...AND THESE ARE BIG AS FAR AS BOTH PRECIP POTENTIAL
AND PTYPE ARE CONCERNED. DECIDED TO NOT CHANGE THIS PERIOD AS IT
WAS BASED ON LATEST WPC...WHICH LOOKS OK AT THIS POINT.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND LATE TONIGHT FOR AKZ027.
MARINE...GALE WARNING FOR PKZ036-041>043.
         SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







  [top]

000
FXAK68 PAFC 221351
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
451 AM AKST MON DEC 22 2014

.ANALYSIS AND UPPER LEVELS...

A WEAK LOW NEAR PRINCE WILLIAM SOUND CONTINUES TO SPIN SNOW AND
RAIN SHOWERS THIS MORNING AS IT DRIFTS NORTH. OVER THE SOUTHWEST
PORTION OF THE STATE...A WEAK AND MOSTLY DRY SHORTWAVE IS SWEEPING
THROUGH THE AREA. FURTHER OUT WEST...ONE FRONT IS WEAKENING OVER
THE WESTERN BERING WHILE ANOTHER IS STRENGTHENING OVER THE NORTH
PACIFIC AND DRIVING TOWARDS THE WESTERN ALEUTIANS. THIS
STRENGTHENING FRONT IS RIDING A 180 KT NORTH PACIFIC JET FROM
SOUTHWEST TO NORTHEAST. THIS JET WILL HELP TO DELIVER THE BIGGEST
WEATHER MAKER TO THE AREA THAT WE WILL SEE OVER THE NEXT FEW DAYS.
A LOW IS DEVELOPING OFF THE KAMCHATKA THIS MORNING AND WILL
RAPIDLY DEEPEN TO AROUND 955 MB AS IT RIDES THE JET THROUGH THE
WESTERN ALEUTIANS INTO TUE MORNING. THE JET THEN WEAKENS AS IT
PARALLELS THE ALEUTIANS FOR A BIT BEFORE DIVING DOWN TO AROUND 35N
SOUTH OF THE AKPEN. IT THEN MAKES A VERY SHARP TURN TOWARD THE
NORTH OVER TOP OF THE NORTH AMERICAN RIDGE AND BARRELS INTO THE
PANHANDLE COAST NEAR HAIDA GWAII AT AROUND 140 KTS.

&&

.MODEL DISCUSSION...

TOUGH WORK CUT OUT FOR THE MODELS IN THIS FORECAST PACKAGE. WITH
THE DEEPENING LOW OUT WEST...THE MODELS ARE IN GOOD AGREEMENT FOR
ONLY ABOUT 24 HOURS THROUGH TUE MORNING...THEN DIVERGE QUITE A BIT
ON THE PLACEMENT OF THE LOW CENTER. THIS IS NOT SURPRISING
CONSIDERING THAT IT IS PROGGED TO BE A RATHER STRONG LOW COMING
FROM A DATA SPARSE REGION. THE EC CONTINUES TO BE THE FURTHEST
EAST AND ELONGATES THE SYSTEM THE FASTEST WHILE THE NAM IS NOW THE
FURTHEST WEST. DISCREPANCIES CONTINUE TO ARISE THROUGH THE WEEK AS
THIS LOW WILL DOMINATE MUCH OF THE PATTERN FOR THE REGION. ALL
MODELS SHOW THE INITIAL WARM FRONT ASSOCIATED WITH THIS SYSTEM
SPREADING PRECIPITATION INTO BRISTOL BAY AND KODIAK ISLAND BY THE
MIDDLE OF THE WEEK. PROBLEM IS THAT THE EC SOLUTION WOULD HAVE IT
TRACKING UP COOK INLET BY WEDNESDAY MORNING WHILE THE AMERICAN
MODELS ARE ESSENTIALLY 24 HOURS LATER. WE DID LEAN TOWARDS THE EC
WITH THIS PACKAGE...BUT MAINLY ONLY THROUGH TUE AS FORECAST
CONFIDENCE WAS LOW BEYOND THAT.

FOR SOUTHCENTRAL FOR THE NEXT 24 TO 36 HOURS...SEVERAL SMALL
FEATURES ARE MAKING FOR A TRICKY FORECAST. THE LOW NEAR PRINCE
WILLIAM SOUND IS FILLING AS IT LIFTS NORTH AND WRAPS SOME MOISTURE
INTO THE ANCHORAGE-MATSU AREA THIS MORNING. A BROAD UPPER LEVEL
TROUGH REMAINS OVER THE NORTHWEST PORTION OF THE MAINLAND WHICH IS
TRYING TO HELP PROVIDE SOME ADDITIONAL CONVERGENCE. THEN THE
REMNANTS OF AN UPPER LEVEL LOW NEAR KODIAK IS FORECASTED TO MOVE
RIGHT THROUGH THE AREA LATER TODAY. COUPLE ALL THESE SMALL
FEATURES WITH WEAK FLOW ALOFT AND THE RESULT IS A FORECAST BASED
ON A MODEL CONSENSUS WITH A GOOD AMOUNT OF FORECASTER DISCRETION.
EITHER WAY...THIS SHOULD NOT BE A BIG WEATHER MAKER WITH THE MOST
LIKELY IMPACT BEING SOME SNOW BANDS SETTING UP AND PUTTING A FEW
INCHES OF SNOW IN LOCALIZED AREAS...VERY SIMILAR TO SUNDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT COUPLE OF
DAYS DUE TO CONTINUED POOR MODEL HANDLING OF KEY FEATURES.
OVERALL FLOW WILL BE SOUTHERLY BRINGING IN MOISTURE FROM THE GULF.
THAT COMBINED WITH INSTABILITY OVER THE AREA WILL RESULT IN
CONTINUED SHOWERS THROUGH TONIGHT. THESE SHOWERS WILL BE LIGHT FOR
THE MOST PART BUT THERE IS A POSSIBILITY OF SOME BANDING THAT
WOULD RESULT IN SMALL AREAS SEEING HIGHER AMOUNTS. THINGS WILL
START TO LIGHTEN UP LATER ON TUESDAY AS WEAK RIDGING MOVES IN OVER
THE AREA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE WESTERN BERING SEA WILL HAVE A STORM FORCE LOW TRACKING INTO
THE BERING SEA BY LATE TUESDAY EVENING. AN ASSOCIATED WEATHER
FRONT FROM THE LOW PRESSURE SYSTEM WILL APPROACH THE SOUTHWEST
COASTLINE BY EARLY WEDNESDAY MORNING. THE WINDS WILL SHIFT FROM
LIGHT OFFSHORE TO ONSHORE FLOW AS THE FRONT MOVES INLAND THROUGH
WEDNESDAY. THIS WILL BRING WARMER TEMPERATURES THROUGHOUT
SOUTHWEST ALASKA. THE WARMEST TEMPERATURES WILL BE ALONG THE
COASTLINE IN THE MID 20S TO MID TEENS INLAND. THE PRECIPITATION
WILL PREDOMINANTLY BE SNOW DUE TO COLD TEMPERATURES ALREADY IN
PLACE IN THE REGION. THERE IS A SLIGHT POTENTIAL FOR LIGHT
FREEZING RAIN WITH THE WARM AIR ADVECTION ALOFT MOVING OVER THE
COLDER TEMPERATURES AT THE SURFACE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
AN UPPER LEVEL CLOSED LOW MOVES INTO WESTERN ALEUTIANS BY EARLY
TUESDAY MORNING. THIS SYNOPTIC FEATURE WILL BE REFLECTED AT THE
SURFACE WITH A STORM FORCE LOW POSITIONED OVER SHEMYA. THE
ASSOCIATED WEATHER FRONT WILL EXTEND FROM THE LOW PRESSURE
SOUTHWARD BETWEEN ADAK AND ATKA INTO THE PACIFIC OCEAN. THIS
SYSTEM WILL TRACK INTO THE WESTERN BERING SEA AND TRACK JUST WEST
OF SHEMYA BY WEDNESDAY EVENING BEFORE TRANSITIONING TO AN OCCLUDED
LOW PRESSURE SYSTEM. THIS WILL BRING WARMER TEMPERATURES WITH
PRECIPITATION STARTING OUT AS A WINTRY MIX BEFORE TRANSITIONING TO
ALL RAIN WITH THE WARM AIR ADVECTION INTO THE WESTERN AND CENTRAL
BERING SEA THROUGH WEDNESDAY. THIS STRONG SYSTEM WILL BRING VERY
WINDY CONDITIONS THROUGH THE WESTERN ALEUTIANS BEFORE SPREADING
INTO THE BERING SEA. THERE WILL BE A HIGH WIND WATCH ISSUED THIS
MORNING FOR THE WESTERN ALEUTIANS FROM SHEMYA EASTWARD INTO ADAK
FOR TUESDAY MORNING THROUGH TUESDAY AFTERNOON. THE AFOREMENTIONED
WEATHER FRONT LOCATED THROUGH THE WESTERN ALEUTIANS WILL TRACK
EASTWARD BEFORE MOVING THROUGH THE PRIBILOF ISLANDS AND EXTEND
SOUTHWARD JUST WEST OF UNALASKA BY TUESDAY AFTERNOON. THIS WEATHER
FRONT WILL REACH THE SOUTHWEST ALASKA COASTLINE BY EARLY WEDNESDAY
MORNING BEFORE MOVING INLAND AND DISSIPATING. THIS WEATHER FRONT
WILL HAVE A SWATH OF GALE TO STORM FORCE WINDS ALONG AND AHEAD OF
THE FRONT AS IT MOVES THROUGH THE ALEUTIAN CHAIN AND THROUGH THE
BERING SEA.



&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MAIN FEATURE IMPACTING THE REGION WEDNESDAY INTO THURSDAY
WILL BE THE FRONT ASSOCIATED WITH THE STORM FORCE LOW OVER THE
WESTERN BERING AND A TRIPLE POINT LOW THAT FORMS ALONG THE FRONT
AND THEN MOVES INTO THE GULF. THE BIGGEST FORECAST CHALLENGE WITH
THESE FEATURES WILL BE THE AFOREMENTIONED TIMING ISSUES WITH THE
EC/GEM SOLUTIONS RUNNING WELL AHEAD OF THE GFS/NAM. HAVE A SLIGHT
PREFERENCE TOWARDS THE FASTER EC SOLUTION FOR NOW...BUT WILL HAVE
TO CONTINUE TO CLOSELY MONITOR THE TIMING OF THESE FEATURES OVER
THE COMING DAYS.

GENERALLY SHOWERY CONDITIONS WILL THEN PERSIST ACROSS THE REGION
INTO THE WEEKEND IN THE WAKE OF THE FRONT AS A LONGWAVE TROUGH
REMAINS CENTERED OVER THE WESTERN BERING AND A SERIES OF
DISTURBANCES TRACK TOWARDS THE GULF IN BROAD SOUTH TO
SOUTHWESTERLY FLOW. GUIDANCE IS HINTING AT ANOTHER DEEP NORTH
PACIFIC LOW MOVING INTO THE BERING TOWARDS THE END OF THE
WEEK...ALBEIT WITH SIGNIFICANT DISCREPANCIES REGARDING PLACEMENT
AND TIMING. DESPITE THESE DIFFERENCES...THIS WOULD GENERALLY
RESULT IN ANOTHER ROUND OF WINDY AND RAINY CONDITIONS ACROSS THE
BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WATCH 187 191
MARINE...STORM WARNING 175 176 177 178 185
 GALE WARNING 155 165 170 171 172 173 174 179 180 181
 HEAVY FREEZING SPRAY 180 181
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...CB




000
FXAK68 PAFC 221351
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
451 AM AKST MON DEC 22 2014

.ANALYSIS AND UPPER LEVELS...

A WEAK LOW NEAR PRINCE WILLIAM SOUND CONTINUES TO SPIN SNOW AND
RAIN SHOWERS THIS MORNING AS IT DRIFTS NORTH. OVER THE SOUTHWEST
PORTION OF THE STATE...A WEAK AND MOSTLY DRY SHORTWAVE IS SWEEPING
THROUGH THE AREA. FURTHER OUT WEST...ONE FRONT IS WEAKENING OVER
THE WESTERN BERING WHILE ANOTHER IS STRENGTHENING OVER THE NORTH
PACIFIC AND DRIVING TOWARDS THE WESTERN ALEUTIANS. THIS
STRENGTHENING FRONT IS RIDING A 180 KT NORTH PACIFIC JET FROM
SOUTHWEST TO NORTHEAST. THIS JET WILL HELP TO DELIVER THE BIGGEST
WEATHER MAKER TO THE AREA THAT WE WILL SEE OVER THE NEXT FEW DAYS.
A LOW IS DEVELOPING OFF THE KAMCHATKA THIS MORNING AND WILL
RAPIDLY DEEPEN TO AROUND 955 MB AS IT RIDES THE JET THROUGH THE
WESTERN ALEUTIANS INTO TUE MORNING. THE JET THEN WEAKENS AS IT
PARALLELS THE ALEUTIANS FOR A BIT BEFORE DIVING DOWN TO AROUND 35N
SOUTH OF THE AKPEN. IT THEN MAKES A VERY SHARP TURN TOWARD THE
NORTH OVER TOP OF THE NORTH AMERICAN RIDGE AND BARRELS INTO THE
PANHANDLE COAST NEAR HAIDA GWAII AT AROUND 140 KTS.

&&

.MODEL DISCUSSION...

TOUGH WORK CUT OUT FOR THE MODELS IN THIS FORECAST PACKAGE. WITH
THE DEEPENING LOW OUT WEST...THE MODELS ARE IN GOOD AGREEMENT FOR
ONLY ABOUT 24 HOURS THROUGH TUE MORNING...THEN DIVERGE QUITE A BIT
ON THE PLACEMENT OF THE LOW CENTER. THIS IS NOT SURPRISING
CONSIDERING THAT IT IS PROGGED TO BE A RATHER STRONG LOW COMING
FROM A DATA SPARSE REGION. THE EC CONTINUES TO BE THE FURTHEST
EAST AND ELONGATES THE SYSTEM THE FASTEST WHILE THE NAM IS NOW THE
FURTHEST WEST. DISCREPANCIES CONTINUE TO ARISE THROUGH THE WEEK AS
THIS LOW WILL DOMINATE MUCH OF THE PATTERN FOR THE REGION. ALL
MODELS SHOW THE INITIAL WARM FRONT ASSOCIATED WITH THIS SYSTEM
SPREADING PRECIPITATION INTO BRISTOL BAY AND KODIAK ISLAND BY THE
MIDDLE OF THE WEEK. PROBLEM IS THAT THE EC SOLUTION WOULD HAVE IT
TRACKING UP COOK INLET BY WEDNESDAY MORNING WHILE THE AMERICAN
MODELS ARE ESSENTIALLY 24 HOURS LATER. WE DID LEAN TOWARDS THE EC
WITH THIS PACKAGE...BUT MAINLY ONLY THROUGH TUE AS FORECAST
CONFIDENCE WAS LOW BEYOND THAT.

FOR SOUTHCENTRAL FOR THE NEXT 24 TO 36 HOURS...SEVERAL SMALL
FEATURES ARE MAKING FOR A TRICKY FORECAST. THE LOW NEAR PRINCE
WILLIAM SOUND IS FILLING AS IT LIFTS NORTH AND WRAPS SOME MOISTURE
INTO THE ANCHORAGE-MATSU AREA THIS MORNING. A BROAD UPPER LEVEL
TROUGH REMAINS OVER THE NORTHWEST PORTION OF THE MAINLAND WHICH IS
TRYING TO HELP PROVIDE SOME ADDITIONAL CONVERGENCE. THEN THE
REMNANTS OF AN UPPER LEVEL LOW NEAR KODIAK IS FORECASTED TO MOVE
RIGHT THROUGH THE AREA LATER TODAY. COUPLE ALL THESE SMALL
FEATURES WITH WEAK FLOW ALOFT AND THE RESULT IS A FORECAST BASED
ON A MODEL CONSENSUS WITH A GOOD AMOUNT OF FORECASTER DISCRETION.
EITHER WAY...THIS SHOULD NOT BE A BIG WEATHER MAKER WITH THE MOST
LIKELY IMPACT BEING SOME SNOW BANDS SETTING UP AND PUTTING A FEW
INCHES OF SNOW IN LOCALIZED AREAS...VERY SIMILAR TO SUNDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT COUPLE OF
DAYS DUE TO CONTINUED POOR MODEL HANDLING OF KEY FEATURES.
OVERALL FLOW WILL BE SOUTHERLY BRINGING IN MOISTURE FROM THE GULF.
THAT COMBINED WITH INSTABILITY OVER THE AREA WILL RESULT IN
CONTINUED SHOWERS THROUGH TONIGHT. THESE SHOWERS WILL BE LIGHT FOR
THE MOST PART BUT THERE IS A POSSIBILITY OF SOME BANDING THAT
WOULD RESULT IN SMALL AREAS SEEING HIGHER AMOUNTS. THINGS WILL
START TO LIGHTEN UP LATER ON TUESDAY AS WEAK RIDGING MOVES IN OVER
THE AREA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE WESTERN BERING SEA WILL HAVE A STORM FORCE LOW TRACKING INTO
THE BERING SEA BY LATE TUESDAY EVENING. AN ASSOCIATED WEATHER
FRONT FROM THE LOW PRESSURE SYSTEM WILL APPROACH THE SOUTHWEST
COASTLINE BY EARLY WEDNESDAY MORNING. THE WINDS WILL SHIFT FROM
LIGHT OFFSHORE TO ONSHORE FLOW AS THE FRONT MOVES INLAND THROUGH
WEDNESDAY. THIS WILL BRING WARMER TEMPERATURES THROUGHOUT
SOUTHWEST ALASKA. THE WARMEST TEMPERATURES WILL BE ALONG THE
COASTLINE IN THE MID 20S TO MID TEENS INLAND. THE PRECIPITATION
WILL PREDOMINANTLY BE SNOW DUE TO COLD TEMPERATURES ALREADY IN
PLACE IN THE REGION. THERE IS A SLIGHT POTENTIAL FOR LIGHT
FREEZING RAIN WITH THE WARM AIR ADVECTION ALOFT MOVING OVER THE
COLDER TEMPERATURES AT THE SURFACE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
AN UPPER LEVEL CLOSED LOW MOVES INTO WESTERN ALEUTIANS BY EARLY
TUESDAY MORNING. THIS SYNOPTIC FEATURE WILL BE REFLECTED AT THE
SURFACE WITH A STORM FORCE LOW POSITIONED OVER SHEMYA. THE
ASSOCIATED WEATHER FRONT WILL EXTEND FROM THE LOW PRESSURE
SOUTHWARD BETWEEN ADAK AND ATKA INTO THE PACIFIC OCEAN. THIS
SYSTEM WILL TRACK INTO THE WESTERN BERING SEA AND TRACK JUST WEST
OF SHEMYA BY WEDNESDAY EVENING BEFORE TRANSITIONING TO AN OCCLUDED
LOW PRESSURE SYSTEM. THIS WILL BRING WARMER TEMPERATURES WITH
PRECIPITATION STARTING OUT AS A WINTRY MIX BEFORE TRANSITIONING TO
ALL RAIN WITH THE WARM AIR ADVECTION INTO THE WESTERN AND CENTRAL
BERING SEA THROUGH WEDNESDAY. THIS STRONG SYSTEM WILL BRING VERY
WINDY CONDITIONS THROUGH THE WESTERN ALEUTIANS BEFORE SPREADING
INTO THE BERING SEA. THERE WILL BE A HIGH WIND WATCH ISSUED THIS
MORNING FOR THE WESTERN ALEUTIANS FROM SHEMYA EASTWARD INTO ADAK
FOR TUESDAY MORNING THROUGH TUESDAY AFTERNOON. THE AFOREMENTIONED
WEATHER FRONT LOCATED THROUGH THE WESTERN ALEUTIANS WILL TRACK
EASTWARD BEFORE MOVING THROUGH THE PRIBILOF ISLANDS AND EXTEND
SOUTHWARD JUST WEST OF UNALASKA BY TUESDAY AFTERNOON. THIS WEATHER
FRONT WILL REACH THE SOUTHWEST ALASKA COASTLINE BY EARLY WEDNESDAY
MORNING BEFORE MOVING INLAND AND DISSIPATING. THIS WEATHER FRONT
WILL HAVE A SWATH OF GALE TO STORM FORCE WINDS ALONG AND AHEAD OF
THE FRONT AS IT MOVES THROUGH THE ALEUTIAN CHAIN AND THROUGH THE
BERING SEA.



&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MAIN FEATURE IMPACTING THE REGION WEDNESDAY INTO THURSDAY
WILL BE THE FRONT ASSOCIATED WITH THE STORM FORCE LOW OVER THE
WESTERN BERING AND A TRIPLE POINT LOW THAT FORMS ALONG THE FRONT
AND THEN MOVES INTO THE GULF. THE BIGGEST FORECAST CHALLENGE WITH
THESE FEATURES WILL BE THE AFOREMENTIONED TIMING ISSUES WITH THE
EC/GEM SOLUTIONS RUNNING WELL AHEAD OF THE GFS/NAM. HAVE A SLIGHT
PREFERENCE TOWARDS THE FASTER EC SOLUTION FOR NOW...BUT WILL HAVE
TO CONTINUE TO CLOSELY MONITOR THE TIMING OF THESE FEATURES OVER
THE COMING DAYS.

GENERALLY SHOWERY CONDITIONS WILL THEN PERSIST ACROSS THE REGION
INTO THE WEEKEND IN THE WAKE OF THE FRONT AS A LONGWAVE TROUGH
REMAINS CENTERED OVER THE WESTERN BERING AND A SERIES OF
DISTURBANCES TRACK TOWARDS THE GULF IN BROAD SOUTH TO
SOUTHWESTERLY FLOW. GUIDANCE IS HINTING AT ANOTHER DEEP NORTH
PACIFIC LOW MOVING INTO THE BERING TOWARDS THE END OF THE
WEEK...ALBEIT WITH SIGNIFICANT DISCREPANCIES REGARDING PLACEMENT
AND TIMING. DESPITE THESE DIFFERENCES...THIS WOULD GENERALLY
RESULT IN ANOTHER ROUND OF WINDY AND RAINY CONDITIONS ACROSS THE
BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WATCH 187 191
MARINE...STORM WARNING 175 176 177 178 185
 GALE WARNING 155 165 170 171 172 173 174 179 180 181
 HEAVY FREEZING SPRAY 180 181
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...CB



000
FXAK68 PAFC 221351
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
451 AM AKST MON DEC 22 2014

.ANALYSIS AND UPPER LEVELS...

A WEAK LOW NEAR PRINCE WILLIAM SOUND CONTINUES TO SPIN SNOW AND
RAIN SHOWERS THIS MORNING AS IT DRIFTS NORTH. OVER THE SOUTHWEST
PORTION OF THE STATE...A WEAK AND MOSTLY DRY SHORTWAVE IS SWEEPING
THROUGH THE AREA. FURTHER OUT WEST...ONE FRONT IS WEAKENING OVER
THE WESTERN BERING WHILE ANOTHER IS STRENGTHENING OVER THE NORTH
PACIFIC AND DRIVING TOWARDS THE WESTERN ALEUTIANS. THIS
STRENGTHENING FRONT IS RIDING A 180 KT NORTH PACIFIC JET FROM
SOUTHWEST TO NORTHEAST. THIS JET WILL HELP TO DELIVER THE BIGGEST
WEATHER MAKER TO THE AREA THAT WE WILL SEE OVER THE NEXT FEW DAYS.
A LOW IS DEVELOPING OFF THE KAMCHATKA THIS MORNING AND WILL
RAPIDLY DEEPEN TO AROUND 955 MB AS IT RIDES THE JET THROUGH THE
WESTERN ALEUTIANS INTO TUE MORNING. THE JET THEN WEAKENS AS IT
PARALLELS THE ALEUTIANS FOR A BIT BEFORE DIVING DOWN TO AROUND 35N
SOUTH OF THE AKPEN. IT THEN MAKES A VERY SHARP TURN TOWARD THE
NORTH OVER TOP OF THE NORTH AMERICAN RIDGE AND BARRELS INTO THE
PANHANDLE COAST NEAR HAIDA GWAII AT AROUND 140 KTS.

&&

.MODEL DISCUSSION...

TOUGH WORK CUT OUT FOR THE MODELS IN THIS FORECAST PACKAGE. WITH
THE DEEPENING LOW OUT WEST...THE MODELS ARE IN GOOD AGREEMENT FOR
ONLY ABOUT 24 HOURS THROUGH TUE MORNING...THEN DIVERGE QUITE A BIT
ON THE PLACEMENT OF THE LOW CENTER. THIS IS NOT SURPRISING
CONSIDERING THAT IT IS PROGGED TO BE A RATHER STRONG LOW COMING
FROM A DATA SPARSE REGION. THE EC CONTINUES TO BE THE FURTHEST
EAST AND ELONGATES THE SYSTEM THE FASTEST WHILE THE NAM IS NOW THE
FURTHEST WEST. DISCREPANCIES CONTINUE TO ARISE THROUGH THE WEEK AS
THIS LOW WILL DOMINATE MUCH OF THE PATTERN FOR THE REGION. ALL
MODELS SHOW THE INITIAL WARM FRONT ASSOCIATED WITH THIS SYSTEM
SPREADING PRECIPITATION INTO BRISTOL BAY AND KODIAK ISLAND BY THE
MIDDLE OF THE WEEK. PROBLEM IS THAT THE EC SOLUTION WOULD HAVE IT
TRACKING UP COOK INLET BY WEDNESDAY MORNING WHILE THE AMERICAN
MODELS ARE ESSENTIALLY 24 HOURS LATER. WE DID LEAN TOWARDS THE EC
WITH THIS PACKAGE...BUT MAINLY ONLY THROUGH TUE AS FORECAST
CONFIDENCE WAS LOW BEYOND THAT.

FOR SOUTHCENTRAL FOR THE NEXT 24 TO 36 HOURS...SEVERAL SMALL
FEATURES ARE MAKING FOR A TRICKY FORECAST. THE LOW NEAR PRINCE
WILLIAM SOUND IS FILLING AS IT LIFTS NORTH AND WRAPS SOME MOISTURE
INTO THE ANCHORAGE-MATSU AREA THIS MORNING. A BROAD UPPER LEVEL
TROUGH REMAINS OVER THE NORTHWEST PORTION OF THE MAINLAND WHICH IS
TRYING TO HELP PROVIDE SOME ADDITIONAL CONVERGENCE. THEN THE
REMNANTS OF AN UPPER LEVEL LOW NEAR KODIAK IS FORECASTED TO MOVE
RIGHT THROUGH THE AREA LATER TODAY. COUPLE ALL THESE SMALL
FEATURES WITH WEAK FLOW ALOFT AND THE RESULT IS A FORECAST BASED
ON A MODEL CONSENSUS WITH A GOOD AMOUNT OF FORECASTER DISCRETION.
EITHER WAY...THIS SHOULD NOT BE A BIG WEATHER MAKER WITH THE MOST
LIKELY IMPACT BEING SOME SNOW BANDS SETTING UP AND PUTTING A FEW
INCHES OF SNOW IN LOCALIZED AREAS...VERY SIMILAR TO SUNDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT COUPLE OF
DAYS DUE TO CONTINUED POOR MODEL HANDLING OF KEY FEATURES.
OVERALL FLOW WILL BE SOUTHERLY BRINGING IN MOISTURE FROM THE GULF.
THAT COMBINED WITH INSTABILITY OVER THE AREA WILL RESULT IN
CONTINUED SHOWERS THROUGH TONIGHT. THESE SHOWERS WILL BE LIGHT FOR
THE MOST PART BUT THERE IS A POSSIBILITY OF SOME BANDING THAT
WOULD RESULT IN SMALL AREAS SEEING HIGHER AMOUNTS. THINGS WILL
START TO LIGHTEN UP LATER ON TUESDAY AS WEAK RIDGING MOVES IN OVER
THE AREA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE WESTERN BERING SEA WILL HAVE A STORM FORCE LOW TRACKING INTO
THE BERING SEA BY LATE TUESDAY EVENING. AN ASSOCIATED WEATHER
FRONT FROM THE LOW PRESSURE SYSTEM WILL APPROACH THE SOUTHWEST
COASTLINE BY EARLY WEDNESDAY MORNING. THE WINDS WILL SHIFT FROM
LIGHT OFFSHORE TO ONSHORE FLOW AS THE FRONT MOVES INLAND THROUGH
WEDNESDAY. THIS WILL BRING WARMER TEMPERATURES THROUGHOUT
SOUTHWEST ALASKA. THE WARMEST TEMPERATURES WILL BE ALONG THE
COASTLINE IN THE MID 20S TO MID TEENS INLAND. THE PRECIPITATION
WILL PREDOMINANTLY BE SNOW DUE TO COLD TEMPERATURES ALREADY IN
PLACE IN THE REGION. THERE IS A SLIGHT POTENTIAL FOR LIGHT
FREEZING RAIN WITH THE WARM AIR ADVECTION ALOFT MOVING OVER THE
COLDER TEMPERATURES AT THE SURFACE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
AN UPPER LEVEL CLOSED LOW MOVES INTO WESTERN ALEUTIANS BY EARLY
TUESDAY MORNING. THIS SYNOPTIC FEATURE WILL BE REFLECTED AT THE
SURFACE WITH A STORM FORCE LOW POSITIONED OVER SHEMYA. THE
ASSOCIATED WEATHER FRONT WILL EXTEND FROM THE LOW PRESSURE
SOUTHWARD BETWEEN ADAK AND ATKA INTO THE PACIFIC OCEAN. THIS
SYSTEM WILL TRACK INTO THE WESTERN BERING SEA AND TRACK JUST WEST
OF SHEMYA BY WEDNESDAY EVENING BEFORE TRANSITIONING TO AN OCCLUDED
LOW PRESSURE SYSTEM. THIS WILL BRING WARMER TEMPERATURES WITH
PRECIPITATION STARTING OUT AS A WINTRY MIX BEFORE TRANSITIONING TO
ALL RAIN WITH THE WARM AIR ADVECTION INTO THE WESTERN AND CENTRAL
BERING SEA THROUGH WEDNESDAY. THIS STRONG SYSTEM WILL BRING VERY
WINDY CONDITIONS THROUGH THE WESTERN ALEUTIANS BEFORE SPREADING
INTO THE BERING SEA. THERE WILL BE A HIGH WIND WATCH ISSUED THIS
MORNING FOR THE WESTERN ALEUTIANS FROM SHEMYA EASTWARD INTO ADAK
FOR TUESDAY MORNING THROUGH TUESDAY AFTERNOON. THE AFOREMENTIONED
WEATHER FRONT LOCATED THROUGH THE WESTERN ALEUTIANS WILL TRACK
EASTWARD BEFORE MOVING THROUGH THE PRIBILOF ISLANDS AND EXTEND
SOUTHWARD JUST WEST OF UNALASKA BY TUESDAY AFTERNOON. THIS WEATHER
FRONT WILL REACH THE SOUTHWEST ALASKA COASTLINE BY EARLY WEDNESDAY
MORNING BEFORE MOVING INLAND AND DISSIPATING. THIS WEATHER FRONT
WILL HAVE A SWATH OF GALE TO STORM FORCE WINDS ALONG AND AHEAD OF
THE FRONT AS IT MOVES THROUGH THE ALEUTIAN CHAIN AND THROUGH THE
BERING SEA.



&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MAIN FEATURE IMPACTING THE REGION WEDNESDAY INTO THURSDAY
WILL BE THE FRONT ASSOCIATED WITH THE STORM FORCE LOW OVER THE
WESTERN BERING AND A TRIPLE POINT LOW THAT FORMS ALONG THE FRONT
AND THEN MOVES INTO THE GULF. THE BIGGEST FORECAST CHALLENGE WITH
THESE FEATURES WILL BE THE AFOREMENTIONED TIMING ISSUES WITH THE
EC/GEM SOLUTIONS RUNNING WELL AHEAD OF THE GFS/NAM. HAVE A SLIGHT
PREFERENCE TOWARDS THE FASTER EC SOLUTION FOR NOW...BUT WILL HAVE
TO CONTINUE TO CLOSELY MONITOR THE TIMING OF THESE FEATURES OVER
THE COMING DAYS.

GENERALLY SHOWERY CONDITIONS WILL THEN PERSIST ACROSS THE REGION
INTO THE WEEKEND IN THE WAKE OF THE FRONT AS A LONGWAVE TROUGH
REMAINS CENTERED OVER THE WESTERN BERING AND A SERIES OF
DISTURBANCES TRACK TOWARDS THE GULF IN BROAD SOUTH TO
SOUTHWESTERLY FLOW. GUIDANCE IS HINTING AT ANOTHER DEEP NORTH
PACIFIC LOW MOVING INTO THE BERING TOWARDS THE END OF THE
WEEK...ALBEIT WITH SIGNIFICANT DISCREPANCIES REGARDING PLACEMENT
AND TIMING. DESPITE THESE DIFFERENCES...THIS WOULD GENERALLY
RESULT IN ANOTHER ROUND OF WINDY AND RAINY CONDITIONS ACROSS THE
BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WATCH 187 191
MARINE...STORM WARNING 175 176 177 178 185
 GALE WARNING 155 165 170 171 172 173 174 179 180 181
 HEAVY FREEZING SPRAY 180 181
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...CB




000
FXAK68 PAFC 221351
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
451 AM AKST MON DEC 22 2014

.ANALYSIS AND UPPER LEVELS...

A WEAK LOW NEAR PRINCE WILLIAM SOUND CONTINUES TO SPIN SNOW AND
RAIN SHOWERS THIS MORNING AS IT DRIFTS NORTH. OVER THE SOUTHWEST
PORTION OF THE STATE...A WEAK AND MOSTLY DRY SHORTWAVE IS SWEEPING
THROUGH THE AREA. FURTHER OUT WEST...ONE FRONT IS WEAKENING OVER
THE WESTERN BERING WHILE ANOTHER IS STRENGTHENING OVER THE NORTH
PACIFIC AND DRIVING TOWARDS THE WESTERN ALEUTIANS. THIS
STRENGTHENING FRONT IS RIDING A 180 KT NORTH PACIFIC JET FROM
SOUTHWEST TO NORTHEAST. THIS JET WILL HELP TO DELIVER THE BIGGEST
WEATHER MAKER TO THE AREA THAT WE WILL SEE OVER THE NEXT FEW DAYS.
A LOW IS DEVELOPING OFF THE KAMCHATKA THIS MORNING AND WILL
RAPIDLY DEEPEN TO AROUND 955 MB AS IT RIDES THE JET THROUGH THE
WESTERN ALEUTIANS INTO TUE MORNING. THE JET THEN WEAKENS AS IT
PARALLELS THE ALEUTIANS FOR A BIT BEFORE DIVING DOWN TO AROUND 35N
SOUTH OF THE AKPEN. IT THEN MAKES A VERY SHARP TURN TOWARD THE
NORTH OVER TOP OF THE NORTH AMERICAN RIDGE AND BARRELS INTO THE
PANHANDLE COAST NEAR HAIDA GWAII AT AROUND 140 KTS.

&&

.MODEL DISCUSSION...

TOUGH WORK CUT OUT FOR THE MODELS IN THIS FORECAST PACKAGE. WITH
THE DEEPENING LOW OUT WEST...THE MODELS ARE IN GOOD AGREEMENT FOR
ONLY ABOUT 24 HOURS THROUGH TUE MORNING...THEN DIVERGE QUITE A BIT
ON THE PLACEMENT OF THE LOW CENTER. THIS IS NOT SURPRISING
CONSIDERING THAT IT IS PROGGED TO BE A RATHER STRONG LOW COMING
FROM A DATA SPARSE REGION. THE EC CONTINUES TO BE THE FURTHEST
EAST AND ELONGATES THE SYSTEM THE FASTEST WHILE THE NAM IS NOW THE
FURTHEST WEST. DISCREPANCIES CONTINUE TO ARISE THROUGH THE WEEK AS
THIS LOW WILL DOMINATE MUCH OF THE PATTERN FOR THE REGION. ALL
MODELS SHOW THE INITIAL WARM FRONT ASSOCIATED WITH THIS SYSTEM
SPREADING PRECIPITATION INTO BRISTOL BAY AND KODIAK ISLAND BY THE
MIDDLE OF THE WEEK. PROBLEM IS THAT THE EC SOLUTION WOULD HAVE IT
TRACKING UP COOK INLET BY WEDNESDAY MORNING WHILE THE AMERICAN
MODELS ARE ESSENTIALLY 24 HOURS LATER. WE DID LEAN TOWARDS THE EC
WITH THIS PACKAGE...BUT MAINLY ONLY THROUGH TUE AS FORECAST
CONFIDENCE WAS LOW BEYOND THAT.

FOR SOUTHCENTRAL FOR THE NEXT 24 TO 36 HOURS...SEVERAL SMALL
FEATURES ARE MAKING FOR A TRICKY FORECAST. THE LOW NEAR PRINCE
WILLIAM SOUND IS FILLING AS IT LIFTS NORTH AND WRAPS SOME MOISTURE
INTO THE ANCHORAGE-MATSU AREA THIS MORNING. A BROAD UPPER LEVEL
TROUGH REMAINS OVER THE NORTHWEST PORTION OF THE MAINLAND WHICH IS
TRYING TO HELP PROVIDE SOME ADDITIONAL CONVERGENCE. THEN THE
REMNANTS OF AN UPPER LEVEL LOW NEAR KODIAK IS FORECASTED TO MOVE
RIGHT THROUGH THE AREA LATER TODAY. COUPLE ALL THESE SMALL
FEATURES WITH WEAK FLOW ALOFT AND THE RESULT IS A FORECAST BASED
ON A MODEL CONSENSUS WITH A GOOD AMOUNT OF FORECASTER DISCRETION.
EITHER WAY...THIS SHOULD NOT BE A BIG WEATHER MAKER WITH THE MOST
LIKELY IMPACT BEING SOME SNOW BANDS SETTING UP AND PUTTING A FEW
INCHES OF SNOW IN LOCALIZED AREAS...VERY SIMILAR TO SUNDAY.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT COUPLE OF
DAYS DUE TO CONTINUED POOR MODEL HANDLING OF KEY FEATURES.
OVERALL FLOW WILL BE SOUTHERLY BRINGING IN MOISTURE FROM THE GULF.
THAT COMBINED WITH INSTABILITY OVER THE AREA WILL RESULT IN
CONTINUED SHOWERS THROUGH TONIGHT. THESE SHOWERS WILL BE LIGHT FOR
THE MOST PART BUT THERE IS A POSSIBILITY OF SOME BANDING THAT
WOULD RESULT IN SMALL AREAS SEEING HIGHER AMOUNTS. THINGS WILL
START TO LIGHTEN UP LATER ON TUESDAY AS WEAK RIDGING MOVES IN OVER
THE AREA.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE WESTERN BERING SEA WILL HAVE A STORM FORCE LOW TRACKING INTO
THE BERING SEA BY LATE TUESDAY EVENING. AN ASSOCIATED WEATHER
FRONT FROM THE LOW PRESSURE SYSTEM WILL APPROACH THE SOUTHWEST
COASTLINE BY EARLY WEDNESDAY MORNING. THE WINDS WILL SHIFT FROM
LIGHT OFFSHORE TO ONSHORE FLOW AS THE FRONT MOVES INLAND THROUGH
WEDNESDAY. THIS WILL BRING WARMER TEMPERATURES THROUGHOUT
SOUTHWEST ALASKA. THE WARMEST TEMPERATURES WILL BE ALONG THE
COASTLINE IN THE MID 20S TO MID TEENS INLAND. THE PRECIPITATION
WILL PREDOMINANTLY BE SNOW DUE TO COLD TEMPERATURES ALREADY IN
PLACE IN THE REGION. THERE IS A SLIGHT POTENTIAL FOR LIGHT
FREEZING RAIN WITH THE WARM AIR ADVECTION ALOFT MOVING OVER THE
COLDER TEMPERATURES AT THE SURFACE.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
AN UPPER LEVEL CLOSED LOW MOVES INTO WESTERN ALEUTIANS BY EARLY
TUESDAY MORNING. THIS SYNOPTIC FEATURE WILL BE REFLECTED AT THE
SURFACE WITH A STORM FORCE LOW POSITIONED OVER SHEMYA. THE
ASSOCIATED WEATHER FRONT WILL EXTEND FROM THE LOW PRESSURE
SOUTHWARD BETWEEN ADAK AND ATKA INTO THE PACIFIC OCEAN. THIS
SYSTEM WILL TRACK INTO THE WESTERN BERING SEA AND TRACK JUST WEST
OF SHEMYA BY WEDNESDAY EVENING BEFORE TRANSITIONING TO AN OCCLUDED
LOW PRESSURE SYSTEM. THIS WILL BRING WARMER TEMPERATURES WITH
PRECIPITATION STARTING OUT AS A WINTRY MIX BEFORE TRANSITIONING TO
ALL RAIN WITH THE WARM AIR ADVECTION INTO THE WESTERN AND CENTRAL
BERING SEA THROUGH WEDNESDAY. THIS STRONG SYSTEM WILL BRING VERY
WINDY CONDITIONS THROUGH THE WESTERN ALEUTIANS BEFORE SPREADING
INTO THE BERING SEA. THERE WILL BE A HIGH WIND WATCH ISSUED THIS
MORNING FOR THE WESTERN ALEUTIANS FROM SHEMYA EASTWARD INTO ADAK
FOR TUESDAY MORNING THROUGH TUESDAY AFTERNOON. THE AFOREMENTIONED
WEATHER FRONT LOCATED THROUGH THE WESTERN ALEUTIANS WILL TRACK
EASTWARD BEFORE MOVING THROUGH THE PRIBILOF ISLANDS AND EXTEND
SOUTHWARD JUST WEST OF UNALASKA BY TUESDAY AFTERNOON. THIS WEATHER
FRONT WILL REACH THE SOUTHWEST ALASKA COASTLINE BY EARLY WEDNESDAY
MORNING BEFORE MOVING INLAND AND DISSIPATING. THIS WEATHER FRONT
WILL HAVE A SWATH OF GALE TO STORM FORCE WINDS ALONG AND AHEAD OF
THE FRONT AS IT MOVES THROUGH THE ALEUTIAN CHAIN AND THROUGH THE
BERING SEA.



&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
THE MAIN FEATURE IMPACTING THE REGION WEDNESDAY INTO THURSDAY
WILL BE THE FRONT ASSOCIATED WITH THE STORM FORCE LOW OVER THE
WESTERN BERING AND A TRIPLE POINT LOW THAT FORMS ALONG THE FRONT
AND THEN MOVES INTO THE GULF. THE BIGGEST FORECAST CHALLENGE WITH
THESE FEATURES WILL BE THE AFOREMENTIONED TIMING ISSUES WITH THE
EC/GEM SOLUTIONS RUNNING WELL AHEAD OF THE GFS/NAM. HAVE A SLIGHT
PREFERENCE TOWARDS THE FASTER EC SOLUTION FOR NOW...BUT WILL HAVE
TO CONTINUE TO CLOSELY MONITOR THE TIMING OF THESE FEATURES OVER
THE COMING DAYS.

GENERALLY SHOWERY CONDITIONS WILL THEN PERSIST ACROSS THE REGION
INTO THE WEEKEND IN THE WAKE OF THE FRONT AS A LONGWAVE TROUGH
REMAINS CENTERED OVER THE WESTERN BERING AND A SERIES OF
DISTURBANCES TRACK TOWARDS THE GULF IN BROAD SOUTH TO
SOUTHWESTERLY FLOW. GUIDANCE IS HINTING AT ANOTHER DEEP NORTH
PACIFIC LOW MOVING INTO THE BERING TOWARDS THE END OF THE
WEEK...ALBEIT WITH SIGNIFICANT DISCREPANCIES REGARDING PLACEMENT
AND TIMING. DESPITE THESE DIFFERENCES...THIS WOULD GENERALLY
RESULT IN ANOTHER ROUND OF WINDY AND RAINY CONDITIONS ACROSS THE
BERING.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...HIGH WIND WATCH 187 191
MARINE...STORM WARNING 175 176 177 178 185
 GALE WARNING 155 165 170 171 172 173 174 179 180 181
 HEAVY FREEZING SPRAY 180 181
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MSO
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...CB


  [top]

000
FXAK69 PAFG 221147
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
247 AM AKST MON DEC 22 2014

.DISCUSSION...

QUIET WEATHER PATTERN IS EXPECTED TO CONTINUE OVER NORTHERN
ALASKA THROUGH FRI. SOMEWHAT COLDER TEMPERATURES CAN BE
EXPECTED OVER THE ARCTIC COAST AND MOST OF THE INTERIOR FOR
MOST OF THIS WEEK...WITH A WARMING TREND BEGINNING OVER THE
WEEKEND

UPPER AIR...
CURRENT GFS/NAM OPERATIONAL RUNS ARE SIMILAR THROUGH WED
NIGHT. A COLD UPPER LEVEL TROUGH EXTENDS FROM A WEAK LOW NEAR THE
NEW SIBERIAN ISLANDS SOUTHEASTWARD ALONG THE NORTHERN SIBERIA
COAST TO THE BERING STRAIT AND NORTON SOUND. THIS TROUGH AND ITS
COLDER AIR MASS WILL MOVE SLOWLY EASTWARD ACROSS THE NORTHERN TWO
THIRDS OF NORTHERN ALASKA THROUGH WED NIGHT. THE ECMWF RUN DIFFERS
FROM THE NAM/GFS...DEPICTING A SMOOTHER AND LOWER AMPLITUDE LONG
WAVE TROUGH WITH THE COLDEST AIR REMAINING NORTH OF THE ARCTIC
COAST. A WEAK SHORT WAVE MOVING OUT OF THE LONG WAVE PATTERN IS
CARRIED EASTWARD ACROSS NORTHERN ALASKA FROM THE BROOKS NORTHWARD
WITH TIMING SIMILAR TO THE MOVEMENT OF THE MAIN TROUGH ON THE
GFS/NAM RUNS. THE OPERATIONAL GFS SOLUTION IS WELL SUPPORTED BY
ITS ENSEMBLE MEAN. WE PREFER THE NAM/GFS CONSENSUS ON THE
HANDLING OF THIS UPPER TROUGH.

AFTER THE UPPER TROUGH EXITS TO THE NORTHEAST...A WEAK UPPER FLOW
PATTERN WILL BE MAINTAINED OVER NORTHERN ALASKA THROUGH FRI. THIS
WILL BE FOLLOWED BY THE DEVELOPMENT OF A HIGH AMPLITUDE UPPER
RIDGE WHICH WILL PUSH NORTHWARD INTO EASTERN ALASKA OVER THE
WEEKEND. THERE ARE MINOR DIFFERENCES BETWEEN THE GFS/ECMWF
OPERATIONAL RUNS BUT GOOD AGREEMENT BETWEEN THE GEFS/NAEFS AND
ECMWF ENSEMBLE MEANS. STRONG SOUTHERLY FLOW ON THE BACK SIDE OF
THE RIDGE WILL BRING WARMER TEMPERATURES TO NORTHERN
ALASKA...ESPECIALLY SOUTH OF THE BROOKS RANGE WHERE THE ENSEMBLE
MEANS ARE INDICATING 850 MB TEMPERATURES AS WARM AS -4C. BEHIND
THE RIDGE...AN UPPER LOW WILL INTO THE SOUTHERN BERING SEA.
POSITIONS FROM OF THE OPERATIONAL RUNS DIFFER...SO PREFER THE
ENSEMBLE MEANS WHICH HAVE A MEAN CENTER NEAR 55N/175-180W SAT
AFTERNOON.

SURFACE...
WINDS OVER THE NORTHWEST CAPES AND THE BERING STRAIT HAVE
DIMINISHED SINCE YESTERDAY WITH THE PRESSURE GRADIENT LOOSENING
NOTICEABLY SINCE FRI EVENING. EXTENSIVE STRATUS COVERS THE
NORTHERN BERING SEA...MUCH OF THE WEST COAST AND WESTERN/CENTRAL
INTERIOR AND ARCTIC COAST. THERE ARE AREAS OF STRATUS OVER PARTS
OF THE EASTERN AND NORTHEAST INTERIOR. WHILE A COLDER AIRMASS IS
EXPECTED OVER THE NORTHERN TWO THIRDS OF NORTHERN ALASKA FOR THE
NEXT FEW DAYS...SURFACE TEMPERATURES WILL BE CLOUD COVER
DEPENDENT...WITH MITIGATION OF THE AIR MASS RADIATIVE TEMPERATURES
IN AREAS OF STRATUS. A GENERALLY LIGHT WIND FLOW PATTERN WILL
CONTINUE OVER THE MAINLAND THROUGH WED.

SCATTERED SNOW SHOWERS TODAY OVER THE WEST COAST FROM THE
NORTHERN SEWARD PENINSULA NORTHWARD...NORTHWESTERN INTERIOR...AND
WESTERN PARTS OF THE ARCTIC SLOPE/BROOKS RANGE. SCATTERED SNOW
SHOWERS WILL SPREAD EASTWARD ACROSS THE REMAINDER OF NORTHERN
ALASKA THROUGH TUE AS THE UPPER LEVEL TROUGH MOVES EAST.

NOTICEABLY WARMER TEMPERATURES ARE EXPECTED OVER MOST OF NORTHERN
ALASKA BY SUN AS THE STRONG UPPER RIDGE BUILDS IN. CHINOOK WINDS
WILL LIKELY DEVELOP IN ALASKA RANGE PASSES SAT. EASTERLY GALES
ARE EXPECTED TO DEVELOP OVER THE NORTHERN BERING SEA INCLUDING ST
LAWRENCE ISLAND SAT AFTERNOON OR EVENING AS A MODERATELY STRONG
STORM MOVES NORTHWARD INTO THE BERING SEA. BY SAT EVENING...GEFS
ENSEMBLE MEAN PLACING A MEAN 962 MB CENTER ABOUT 150 MILES
SOUTHWEST OF ST MATTHEW ISLAND. CONSENSUS OF THE CURRENT GFS/ECMWF
OPERATIONAL RUNS PUTS THE LOW CENTER ABOUT 50-100 MILES EAST OF
THIS POSITION SAT EVENING. PRECIPITATION ASSOCIATED WITH THIS
SYSTEM EXPECTED TO SPREAD NORTHWARD TO THE SOUTHWEST INTERIOR AND
SOUTHERN WEST COAST SAT AFTERNOON. TEMPERATURES COULD BE WARM
ENOUGH FOR MIXED PRECIPITATION IN AREAS OF THE WEST COAST SOUTH OF
NORTON SOUND AS INDICATED BY GFS MODEL SOUNDINGS.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

HEAVY FREEZING SPRAY WARNING...PKZ210.


$$

RF DEC 14




000
FXAK69 PAFG 221147
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
247 AM AKST MON DEC 22 2014

.DISCUSSION...

QUIET WEATHER PATTERN IS EXPECTED TO CONTINUE OVER NORTHERN
ALASKA THROUGH FRI. SOMEWHAT COLDER TEMPERATURES CAN BE
EXPECTED OVER THE ARCTIC COAST AND MOST OF THE INTERIOR FOR
MOST OF THIS WEEK...WITH A WARMING TREND BEGINNING OVER THE
WEEKEND

UPPER AIR...
CURRENT GFS/NAM OPERATIONAL RUNS ARE SIMILAR THROUGH WED
NIGHT. A COLD UPPER LEVEL TROUGH EXTENDS FROM A WEAK LOW NEAR THE
NEW SIBERIAN ISLANDS SOUTHEASTWARD ALONG THE NORTHERN SIBERIA
COAST TO THE BERING STRAIT AND NORTON SOUND. THIS TROUGH AND ITS
COLDER AIR MASS WILL MOVE SLOWLY EASTWARD ACROSS THE NORTHERN TWO
THIRDS OF NORTHERN ALASKA THROUGH WED NIGHT. THE ECMWF RUN DIFFERS
FROM THE NAM/GFS...DEPICTING A SMOOTHER AND LOWER AMPLITUDE LONG
WAVE TROUGH WITH THE COLDEST AIR REMAINING NORTH OF THE ARCTIC
COAST. A WEAK SHORT WAVE MOVING OUT OF THE LONG WAVE PATTERN IS
CARRIED EASTWARD ACROSS NORTHERN ALASKA FROM THE BROOKS NORTHWARD
WITH TIMING SIMILAR TO THE MOVEMENT OF THE MAIN TROUGH ON THE
GFS/NAM RUNS. THE OPERATIONAL GFS SOLUTION IS WELL SUPPORTED BY
ITS ENSEMBLE MEAN. WE PREFER THE NAM/GFS CONSENSUS ON THE
HANDLING OF THIS UPPER TROUGH.

AFTER THE UPPER TROUGH EXITS TO THE NORTHEAST...A WEAK UPPER FLOW
PATTERN WILL BE MAINTAINED OVER NORTHERN ALASKA THROUGH FRI. THIS
WILL BE FOLLOWED BY THE DEVELOPMENT OF A HIGH AMPLITUDE UPPER
RIDGE WHICH WILL PUSH NORTHWARD INTO EASTERN ALASKA OVER THE
WEEKEND. THERE ARE MINOR DIFFERENCES BETWEEN THE GFS/ECMWF
OPERATIONAL RUNS BUT GOOD AGREEMENT BETWEEN THE GEFS/NAEFS AND
ECMWF ENSEMBLE MEANS. STRONG SOUTHERLY FLOW ON THE BACK SIDE OF
THE RIDGE WILL BRING WARMER TEMPERATURES TO NORTHERN
ALASKA...ESPECIALLY SOUTH OF THE BROOKS RANGE WHERE THE ENSEMBLE
MEANS ARE INDICATING 850 MB TEMPERATURES AS WARM AS -4C. BEHIND
THE RIDGE...AN UPPER LOW WILL INTO THE SOUTHERN BERING SEA.
POSITIONS FROM OF THE OPERATIONAL RUNS DIFFER...SO PREFER THE
ENSEMBLE MEANS WHICH HAVE A MEAN CENTER NEAR 55N/175-180W SAT
AFTERNOON.

SURFACE...
WINDS OVER THE NORTHWEST CAPES AND THE BERING STRAIT HAVE
DIMINISHED SINCE YESTERDAY WITH THE PRESSURE GRADIENT LOOSENING
NOTICEABLY SINCE FRI EVENING. EXTENSIVE STRATUS COVERS THE
NORTHERN BERING SEA...MUCH OF THE WEST COAST AND WESTERN/CENTRAL
INTERIOR AND ARCTIC COAST. THERE ARE AREAS OF STRATUS OVER PARTS
OF THE EASTERN AND NORTHEAST INTERIOR. WHILE A COLDER AIRMASS IS
EXPECTED OVER THE NORTHERN TWO THIRDS OF NORTHERN ALASKA FOR THE
NEXT FEW DAYS...SURFACE TEMPERATURES WILL BE CLOUD COVER
DEPENDENT...WITH MITIGATION OF THE AIR MASS RADIATIVE TEMPERATURES
IN AREAS OF STRATUS. A GENERALLY LIGHT WIND FLOW PATTERN WILL
CONTINUE OVER THE MAINLAND THROUGH WED.

SCATTERED SNOW SHOWERS TODAY OVER THE WEST COAST FROM THE
NORTHERN SEWARD PENINSULA NORTHWARD...NORTHWESTERN INTERIOR...AND
WESTERN PARTS OF THE ARCTIC SLOPE/BROOKS RANGE. SCATTERED SNOW
SHOWERS WILL SPREAD EASTWARD ACROSS THE REMAINDER OF NORTHERN
ALASKA THROUGH TUE AS THE UPPER LEVEL TROUGH MOVES EAST.

NOTICEABLY WARMER TEMPERATURES ARE EXPECTED OVER MOST OF NORTHERN
ALASKA BY SUN AS THE STRONG UPPER RIDGE BUILDS IN. CHINOOK WINDS
WILL LIKELY DEVELOP IN ALASKA RANGE PASSES SAT. EASTERLY GALES
ARE EXPECTED TO DEVELOP OVER THE NORTHERN BERING SEA INCLUDING ST
LAWRENCE ISLAND SAT AFTERNOON OR EVENING AS A MODERATELY STRONG
STORM MOVES NORTHWARD INTO THE BERING SEA. BY SAT EVENING...GEFS
ENSEMBLE MEAN PLACING A MEAN 962 MB CENTER ABOUT 150 MILES
SOUTHWEST OF ST MATTHEW ISLAND. CONSENSUS OF THE CURRENT GFS/ECMWF
OPERATIONAL RUNS PUTS THE LOW CENTER ABOUT 50-100 MILES EAST OF
THIS POSITION SAT EVENING. PRECIPITATION ASSOCIATED WITH THIS
SYSTEM EXPECTED TO SPREAD NORTHWARD TO THE SOUTHWEST INTERIOR AND
SOUTHERN WEST COAST SAT AFTERNOON. TEMPERATURES COULD BE WARM
ENOUGH FOR MIXED PRECIPITATION IN AREAS OF THE WEST COAST SOUTH OF
NORTON SOUND AS INDICATED BY GFS MODEL SOUNDINGS.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

HEAVY FREEZING SPRAY WARNING...PKZ210.


$$

RF DEC 14



000
FXAK68 PAFC 220119
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
419 PM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL TROUGH EXTENDS FROM THE WEST COAST OF ALASKA SOUTHWARD
INTO THE NORTH PACIFIC. THE JET REMAINS LARGELY SUPPRESSED WELL
SOUTH OF MAINLAND ALASKA...WITH A 200 KT JET EXITING ASIA AND
HEADING INTO THE LONGWAVE TROUGH AND A 180 KT JET COMING OUT OF
THE TROUGH AND SLAMMING INTO THE SOUTHERN PANHANDLE. A DECAYING
VERTICALLY STACKED LOW IN THE WESTERN GULF IS SLOWLY LIFTING
NORTHWARD WITH NUMEROUS EMBEDDED FEATURES AT THE SURFACE AND ALSO
ALOFT. THIS IS LEADING TO A MORE SHOWERY PATTERN ACROSS SOUTHERN
ALASKA THAN HAS BEEN SEEN RECENTLY. A MORE FOCUSED BAND OF
CONVECTIVE SNOW SHOWERS IS PERSISTING FROM WESTERN PRINCE WILLIAM
SOUND UP TO EAGLE RIVER AND INTO THE SUSITNA VALLEY. SNOWFALL
TOTALS HAVE RANGED FROM 4-7 INCHES NEAR PORTAGE TO UPWARDS OF 2 INCHES
ON THE WEST SIDE OF THE MOUNTAINS. THERE IS ANOTHER WEAK
CIRCULATION EAST OF KODIAK ISLAND HEADING NORTHWARD...WITH
INCREASING SHOWER ACTIVITY ALREADY DEVELOPING ACROSS MUCH OF THE
GULF OF ALASKA AS THIS LOW TEAMS UP WITH COLDER AIR MOVING IN AT
500 MB TO STEEPEN LAPSE RATES ACROSS A LARGE SECTION OF THE GULF.

OUT WEST...WEAK HIGH PRESSURE AND NORTHERLY FLOW ARE ALLOWING
COLD AIR TO STREAM SOUTHWARD FROM THE BERING STRAIT AND PRODUCE
WIDESPREAD SNOW SHOWER ACTIVITY ACROSS MUCH OF THE BERING SEA AND
ALEUTIANS. MEANWHILE...A MATURE STORM NEAR THE KAMCHATKA PENINSULA
OF RUSSIA IS SLINGING A FRONT TOWARD THE WESTERN ALEUTIANS WITH
WINDS AT SHEMYA ALREADY BEGINNING TO INCREASE OUT OF THE SOUTH.

&&

.MODEL DISCUSSION...
THE MODELS REMAIN IN GOOD SYNOPTIC AGREEMENT...BUT CONTINUE TO
STRUGGLE IMMENSELY WITH THE DETAILS OF THE EVOLUTION IN THE GULF
AND ACROSS SOUTHCENTRAL DURING THE NEXT 24-36 HOURS. THE MAIN
PLAYERS ARE THE COLD AIR ALOFT MOVING IN FROM THE SOUTH THAT WILL
FURTHER DESTABILIZE THE ATMOSPHERE AND GIVE AN EXTRA SHOT IN THE
ARM TO SNOW SHOWER ACTIVITY. THANKFULLY THIS IS A BROAD-SCALE
FEATURE AND IS HIGH CONFIDENCE. MUCH LOWER CONFIDENCE ARE THE
MOVEMENT AND STRENGTH OF THE SHORTWAVE MOVING NORTHWARD NEAR
KODIAK ISLAND AS WELL AS THE ABILITY OF ANY LOCALIZED AREAS OF
CONVERGENCE TO FOCUS THIS CONVECTION (FOR EXAMPLE NEAR WESTERN
TURNAGAIN ARM). THE BOTTOM LINE TODAY IS THAT THE SUBTLE DETAILS
IN THE ATMOSPHERE WILL LIKELY PLAY AN EVEN BIGGER ROLE THAN
NORMAL IN DETERMINING WHERE AND HOW MUCH SNOW FALLS ACROSS
SOUTHCENTRAL ALASKA OVER THE NEXT 2 DAYS...AND OUT OF NECESSITY A
MORE BROAD- BRUSHED APPROACH WILL BE EMPLOYED AND RADAR AND
SATELLITE TRENDS WILL BE MONITORED CLOSELY UNTIL SUCH A TIME AS
THE ATMOSPHERE TIPS ITS HAND ABOUT WHAT WILL HAPPEN. AS YOU CAN
IMAGINE...FORECAST CONFIDENCE IS BELOW AVERAGE ACROSS SOUTHCENTRAL
ALASKA.

OUT WEST...THE DEVELOPMENT OF A STRONG LOW IN THE WESTERN BERING
EARLY NEXT WEEK IS BECOMING THE PRIMARY FORECAST CHALLENGE. THE
GFS CONTINUES TO BE FURTHER WEST THAN THE REST OF THE GLOBAL
GUIDANCE...AND WITH GOOD RUN-TO-RUN CONSISTENCY OF THE
ECMWF...WILL TREND THE FORECAST THAT DIRECTION. THE PRIMARY THREAT
WILL BE THE POTENTIAL FOR HIGH WINDS IN THE WESTERN ALEUTIANS AS
THE LOW REACHES PEAK INTENSITY TUESDAY MORNING.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT TWO DAYS.
THE FLOW REGIME DOES NOT CHANGE MUCH AT ALL. COLDER AND MORE
UNSTABLE AIR ALOFT MOVES OVERHEAD FROM THE GULF AND WILL BE THE
FOCUS FOR SNOW SHOWERS ACROSS MUCH OF THE REGION. SHOWERS WILL BE
ENHANCED BY A DISTURBANCE ALOFT...CURRENTLY SITTING IN THE CENTRAL
GULF...AS IT MOVES NORTHWARD LATE TONIGHT INTO TOMORROW MORNING.
INSTABILITY WILL REMAIN OVER THE AREA THROUGH LATE TOMORROW NIGHT
BEFORE THE FLOW BEGINS TO STABILIZE INTO MID-WEEK. ACCUMULATIONS
WILL GENERALLY REMAIN LIGHT BUT COULD ADD UP FAST FOR ANY AREA
WHERE BANDING SITS OVERHEAD FOR A PROLONGED PERIOD OF TIME. FOR
THE MOST PART ANY SHOWERY ACTIVITY SHOULD STAY AS OPEN CELLED IN
NATURE BUT SOME BANDING FROM LOW LEVEL CONVERGENCE ALONG TURNAGAIN
ARM IS NOT OUT OF THE QUESTION.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

NORTHERLY FLOW IN COLD ADVECTION REGIME WILL CONTINUE THROUGH
MONDAY. MODELS DEPICT ENOUGH LOW LEVEL MOISTURE IN THE LOWEST 1K
FEET WHERE SHELTERED AREAS OF SOUTHWEST ALASKA WILL BE CAPABLE OF
DEVELOPING SOME PATCHY FOG...AS HAS OCCURRED TODAY IN PARTS OF THE
KUSKOKWIM VALLEY AND BRISTOL BAY. EXCEPT FOR THE OUTER COAST OF
THE KUSKOKWIM DELTA OUTER COASTLINE TONIGHT...AND ALONG THE ALASKA
AND ALEUTIAN RANGES...PRECIPITATION CHANCES WILL BE ZERO.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

TRANQUIL CONDITIONS BY BERING SEA STANDARDS THE NEXT DAY OR SO
WITH A MINOR DISTURBANCE BRINGING SOME LIKELY RAIN AND SNOW TO
THE WESTERN ALEUTIANS TONIGHT INTO SUNDAY.

THE SYSTEM TO WATCH WILL BEGIN TO MAKE ITS PRESENCE FELT MONDAY
INTO TUESDAY AS A LOW MOVES ACROSS THE WESTERN ALEUTIANS AND INTO
THE WESTERN BERING SEA. THE EUROPEAN (AND TO A LESSER EXTENT THE
GLOBAL CANADIAN) MODEL IS PREFERRED WITH ITS MORE ELONGATED
CIRCULATION ALONG ITS ASSOCIATED WEATHER FRONT. THE GFS (WITH SOME
SUPPORT FROM THE NAM) KEEPS THE LOW A BIT MORE WEST OF THE
EUROPEAN AND CANADIAN MODELS BUT ALSO MORE ANNULAR. REGARDLESS OF
WHICH MODEL IS CORRECT...WITH THE FORECASTED INTENSIFICATION OF
THE LOW THERE IS AN INCREASING LIKELIHOOD OF POWERFUL WESTERLY
WINDS WRAPPING AROUND THE BACKSIDE OF THE LOW OVER THE WESTERN
ALEUTIANS AND NEARBY COASTAL WATERS. IF THE EUROPEAN IS
CORRECT...A THREAT OF THESE STRONGER WINDS COULD ALSO REACH THE
CENTRAL ALEUTIANS AND ITS NEARBY COASTAL WATERS.

THE PRECEDING WEATHER FRONT WILL ALSO CARRY A SWATH OF STRONG
WINDS TO STORM-FORCE ALONG AND JUST AHEAD OF THE FRONT AS IT RACES
ACROSS THE BERING SEA...INTENSIFYING OVER THE SOUTHERN AND WESTERN
BERING MONDAY NIGHT AND REACHING THE PRIBILOFS AND EASTERN
ALEUTIANS DURING THE DAY ON TUESDAY. THE FASTER EC WAS ALSO
PREFERRED OVER THE SLOWER GFS WITH PROGRESSION OF THE FRONT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
AN ACTIVE JET STREAM KEEPS THE WEATHER PATTERN IN MOTION THROUGH
NEXT WEEKEND. MODELS ARE FINALLY STARTING TO COME INTO BETTER SYNOPTIC
AGREEMENT WITH A CLOSED LOW CENTER DEVELOPING TUESDAY NIGHT IN THE
WESTERN BERING AS A LONGWAVE SHIFTS EAST FROM THE KAMCHATKA
PENINSULA. THIS LOW PRESSURE SYSTEM AND A POLAR LOW IN THE ARCTIC
FORCES THE WEAK UPPER TROUGH...CURRENTLY OVER THE GULF OF
ALASKA...TOWARD SOUTHEAST ALASKA MID WEEK. THE PATTERN FOR THE
WEEK AHEAD WILL MAINLY BE DRIVEN BY THE LOW IN THE WESTERN
BERING...HOWEVER THE POLAR LOW WILL PUSH A FRONT FROM THE
NORTHWEST COAST TO THE SOUTHERN MAINLAND WEDNESDAY. THE SHORTWAVES
FROM THESE TWO SYSTEMS WILL BRING SNOW SHOWERS WITH GUSTY WINDS
MAINLY ALONG THE QUICKLY DEVELOPING LOW PRESSURE SYSTEMS DRIVEN
FROM THE BERING LOW. MODEL CONFIDENCE IS LOWER THAN AVERAGE ON THE
UPCOMING SHORTWAVES AND THUS CHANGES IN LONG RANGE FORECAST
PRECIPITATION AND WINDS CAN BE EXPECTED.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM 178.
         GALES 170 172 173 174 175 176 177 185 411 412 413 414
         HEAVY FREEZING SPRAY...180 181.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...KH




000
FXAK68 PAFC 220119
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
419 PM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL TROUGH EXTENDS FROM THE WEST COAST OF ALASKA SOUTHWARD
INTO THE NORTH PACIFIC. THE JET REMAINS LARGELY SUPPRESSED WELL
SOUTH OF MAINLAND ALASKA...WITH A 200 KT JET EXITING ASIA AND
HEADING INTO THE LONGWAVE TROUGH AND A 180 KT JET COMING OUT OF
THE TROUGH AND SLAMMING INTO THE SOUTHERN PANHANDLE. A DECAYING
VERTICALLY STACKED LOW IN THE WESTERN GULF IS SLOWLY LIFTING
NORTHWARD WITH NUMEROUS EMBEDDED FEATURES AT THE SURFACE AND ALSO
ALOFT. THIS IS LEADING TO A MORE SHOWERY PATTERN ACROSS SOUTHERN
ALASKA THAN HAS BEEN SEEN RECENTLY. A MORE FOCUSED BAND OF
CONVECTIVE SNOW SHOWERS IS PERSISTING FROM WESTERN PRINCE WILLIAM
SOUND UP TO EAGLE RIVER AND INTO THE SUSITNA VALLEY. SNOWFALL
TOTALS HAVE RANGED FROM 4-7 INCHES NEAR PORTAGE TO UPWARDS OF 2 INCHES
ON THE WEST SIDE OF THE MOUNTAINS. THERE IS ANOTHER WEAK
CIRCULATION EAST OF KODIAK ISLAND HEADING NORTHWARD...WITH
INCREASING SHOWER ACTIVITY ALREADY DEVELOPING ACROSS MUCH OF THE
GULF OF ALASKA AS THIS LOW TEAMS UP WITH COLDER AIR MOVING IN AT
500 MB TO STEEPEN LAPSE RATES ACROSS A LARGE SECTION OF THE GULF.

OUT WEST...WEAK HIGH PRESSURE AND NORTHERLY FLOW ARE ALLOWING
COLD AIR TO STREAM SOUTHWARD FROM THE BERING STRAIT AND PRODUCE
WIDESPREAD SNOW SHOWER ACTIVITY ACROSS MUCH OF THE BERING SEA AND
ALEUTIANS. MEANWHILE...A MATURE STORM NEAR THE KAMCHATKA PENINSULA
OF RUSSIA IS SLINGING A FRONT TOWARD THE WESTERN ALEUTIANS WITH
WINDS AT SHEMYA ALREADY BEGINNING TO INCREASE OUT OF THE SOUTH.

&&

.MODEL DISCUSSION...
THE MODELS REMAIN IN GOOD SYNOPTIC AGREEMENT...BUT CONTINUE TO
STRUGGLE IMMENSELY WITH THE DETAILS OF THE EVOLUTION IN THE GULF
AND ACROSS SOUTHCENTRAL DURING THE NEXT 24-36 HOURS. THE MAIN
PLAYERS ARE THE COLD AIR ALOFT MOVING IN FROM THE SOUTH THAT WILL
FURTHER DESTABILIZE THE ATMOSPHERE AND GIVE AN EXTRA SHOT IN THE
ARM TO SNOW SHOWER ACTIVITY. THANKFULLY THIS IS A BROAD-SCALE
FEATURE AND IS HIGH CONFIDENCE. MUCH LOWER CONFIDENCE ARE THE
MOVEMENT AND STRENGTH OF THE SHORTWAVE MOVING NORTHWARD NEAR
KODIAK ISLAND AS WELL AS THE ABILITY OF ANY LOCALIZED AREAS OF
CONVERGENCE TO FOCUS THIS CONVECTION (FOR EXAMPLE NEAR WESTERN
TURNAGAIN ARM). THE BOTTOM LINE TODAY IS THAT THE SUBTLE DETAILS
IN THE ATMOSPHERE WILL LIKELY PLAY AN EVEN BIGGER ROLE THAN
NORMAL IN DETERMINING WHERE AND HOW MUCH SNOW FALLS ACROSS
SOUTHCENTRAL ALASKA OVER THE NEXT 2 DAYS...AND OUT OF NECESSITY A
MORE BROAD- BRUSHED APPROACH WILL BE EMPLOYED AND RADAR AND
SATELLITE TRENDS WILL BE MONITORED CLOSELY UNTIL SUCH A TIME AS
THE ATMOSPHERE TIPS ITS HAND ABOUT WHAT WILL HAPPEN. AS YOU CAN
IMAGINE...FORECAST CONFIDENCE IS BELOW AVERAGE ACROSS SOUTHCENTRAL
ALASKA.

OUT WEST...THE DEVELOPMENT OF A STRONG LOW IN THE WESTERN BERING
EARLY NEXT WEEK IS BECOMING THE PRIMARY FORECAST CHALLENGE. THE
GFS CONTINUES TO BE FURTHER WEST THAN THE REST OF THE GLOBAL
GUIDANCE...AND WITH GOOD RUN-TO-RUN CONSISTENCY OF THE
ECMWF...WILL TREND THE FORECAST THAT DIRECTION. THE PRIMARY THREAT
WILL BE THE POTENTIAL FOR HIGH WINDS IN THE WESTERN ALEUTIANS AS
THE LOW REACHES PEAK INTENSITY TUESDAY MORNING.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT TWO DAYS.
THE FLOW REGIME DOES NOT CHANGE MUCH AT ALL. COLDER AND MORE
UNSTABLE AIR ALOFT MOVES OVERHEAD FROM THE GULF AND WILL BE THE
FOCUS FOR SNOW SHOWERS ACROSS MUCH OF THE REGION. SHOWERS WILL BE
ENHANCED BY A DISTURBANCE ALOFT...CURRENTLY SITTING IN THE CENTRAL
GULF...AS IT MOVES NORTHWARD LATE TONIGHT INTO TOMORROW MORNING.
INSTABILITY WILL REMAIN OVER THE AREA THROUGH LATE TOMORROW NIGHT
BEFORE THE FLOW BEGINS TO STABILIZE INTO MID-WEEK. ACCUMULATIONS
WILL GENERALLY REMAIN LIGHT BUT COULD ADD UP FAST FOR ANY AREA
WHERE BANDING SITS OVERHEAD FOR A PROLONGED PERIOD OF TIME. FOR
THE MOST PART ANY SHOWERY ACTIVITY SHOULD STAY AS OPEN CELLED IN
NATURE BUT SOME BANDING FROM LOW LEVEL CONVERGENCE ALONG TURNAGAIN
ARM IS NOT OUT OF THE QUESTION.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

NORTHERLY FLOW IN COLD ADVECTION REGIME WILL CONTINUE THROUGH
MONDAY. MODELS DEPICT ENOUGH LOW LEVEL MOISTURE IN THE LOWEST 1K
FEET WHERE SHELTERED AREAS OF SOUTHWEST ALASKA WILL BE CAPABLE OF
DEVELOPING SOME PATCHY FOG...AS HAS OCCURRED TODAY IN PARTS OF THE
KUSKOKWIM VALLEY AND BRISTOL BAY. EXCEPT FOR THE OUTER COAST OF
THE KUSKOKWIM DELTA OUTER COASTLINE TONIGHT...AND ALONG THE ALASKA
AND ALEUTIAN RANGES...PRECIPITATION CHANCES WILL BE ZERO.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

TRANQUIL CONDITIONS BY BERING SEA STANDARDS THE NEXT DAY OR SO
WITH A MINOR DISTURBANCE BRINGING SOME LIKELY RAIN AND SNOW TO
THE WESTERN ALEUTIANS TONIGHT INTO SUNDAY.

THE SYSTEM TO WATCH WILL BEGIN TO MAKE ITS PRESENCE FELT MONDAY
INTO TUESDAY AS A LOW MOVES ACROSS THE WESTERN ALEUTIANS AND INTO
THE WESTERN BERING SEA. THE EUROPEAN (AND TO A LESSER EXTENT THE
GLOBAL CANADIAN) MODEL IS PREFERRED WITH ITS MORE ELONGATED
CIRCULATION ALONG ITS ASSOCIATED WEATHER FRONT. THE GFS (WITH SOME
SUPPORT FROM THE NAM) KEEPS THE LOW A BIT MORE WEST OF THE
EUROPEAN AND CANADIAN MODELS BUT ALSO MORE ANNULAR. REGARDLESS OF
WHICH MODEL IS CORRECT...WITH THE FORECASTED INTENSIFICATION OF
THE LOW THERE IS AN INCREASING LIKELIHOOD OF POWERFUL WESTERLY
WINDS WRAPPING AROUND THE BACKSIDE OF THE LOW OVER THE WESTERN
ALEUTIANS AND NEARBY COASTAL WATERS. IF THE EUROPEAN IS
CORRECT...A THREAT OF THESE STRONGER WINDS COULD ALSO REACH THE
CENTRAL ALEUTIANS AND ITS NEARBY COASTAL WATERS.

THE PRECEDING WEATHER FRONT WILL ALSO CARRY A SWATH OF STRONG
WINDS TO STORM-FORCE ALONG AND JUST AHEAD OF THE FRONT AS IT RACES
ACROSS THE BERING SEA...INTENSIFYING OVER THE SOUTHERN AND WESTERN
BERING MONDAY NIGHT AND REACHING THE PRIBILOFS AND EASTERN
ALEUTIANS DURING THE DAY ON TUESDAY. THE FASTER EC WAS ALSO
PREFERRED OVER THE SLOWER GFS WITH PROGRESSION OF THE FRONT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
AN ACTIVE JET STREAM KEEPS THE WEATHER PATTERN IN MOTION THROUGH
NEXT WEEKEND. MODELS ARE FINALLY STARTING TO COME INTO BETTER SYNOPTIC
AGREEMENT WITH A CLOSED LOW CENTER DEVELOPING TUESDAY NIGHT IN THE
WESTERN BERING AS A LONGWAVE SHIFTS EAST FROM THE KAMCHATKA
PENINSULA. THIS LOW PRESSURE SYSTEM AND A POLAR LOW IN THE ARCTIC
FORCES THE WEAK UPPER TROUGH...CURRENTLY OVER THE GULF OF
ALASKA...TOWARD SOUTHEAST ALASKA MID WEEK. THE PATTERN FOR THE
WEEK AHEAD WILL MAINLY BE DRIVEN BY THE LOW IN THE WESTERN
BERING...HOWEVER THE POLAR LOW WILL PUSH A FRONT FROM THE
NORTHWEST COAST TO THE SOUTHERN MAINLAND WEDNESDAY. THE SHORTWAVES
FROM THESE TWO SYSTEMS WILL BRING SNOW SHOWERS WITH GUSTY WINDS
MAINLY ALONG THE QUICKLY DEVELOPING LOW PRESSURE SYSTEMS DRIVEN
FROM THE BERING LOW. MODEL CONFIDENCE IS LOWER THAN AVERAGE ON THE
UPCOMING SHORTWAVES AND THUS CHANGES IN LONG RANGE FORECAST
PRECIPITATION AND WINDS CAN BE EXPECTED.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM 178.
         GALES 170 172 173 174 175 176 177 185 411 412 413 414
         HEAVY FREEZING SPRAY...180 181.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...KH



000
FXAK68 PAFC 220119
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
419 PM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL TROUGH EXTENDS FROM THE WEST COAST OF ALASKA SOUTHWARD
INTO THE NORTH PACIFIC. THE JET REMAINS LARGELY SUPPRESSED WELL
SOUTH OF MAINLAND ALASKA...WITH A 200 KT JET EXITING ASIA AND
HEADING INTO THE LONGWAVE TROUGH AND A 180 KT JET COMING OUT OF
THE TROUGH AND SLAMMING INTO THE SOUTHERN PANHANDLE. A DECAYING
VERTICALLY STACKED LOW IN THE WESTERN GULF IS SLOWLY LIFTING
NORTHWARD WITH NUMEROUS EMBEDDED FEATURES AT THE SURFACE AND ALSO
ALOFT. THIS IS LEADING TO A MORE SHOWERY PATTERN ACROSS SOUTHERN
ALASKA THAN HAS BEEN SEEN RECENTLY. A MORE FOCUSED BAND OF
CONVECTIVE SNOW SHOWERS IS PERSISTING FROM WESTERN PRINCE WILLIAM
SOUND UP TO EAGLE RIVER AND INTO THE SUSITNA VALLEY. SNOWFALL
TOTALS HAVE RANGED FROM 4-7 INCHES NEAR PORTAGE TO UPWARDS OF 2 INCHES
ON THE WEST SIDE OF THE MOUNTAINS. THERE IS ANOTHER WEAK
CIRCULATION EAST OF KODIAK ISLAND HEADING NORTHWARD...WITH
INCREASING SHOWER ACTIVITY ALREADY DEVELOPING ACROSS MUCH OF THE
GULF OF ALASKA AS THIS LOW TEAMS UP WITH COLDER AIR MOVING IN AT
500 MB TO STEEPEN LAPSE RATES ACROSS A LARGE SECTION OF THE GULF.

OUT WEST...WEAK HIGH PRESSURE AND NORTHERLY FLOW ARE ALLOWING
COLD AIR TO STREAM SOUTHWARD FROM THE BERING STRAIT AND PRODUCE
WIDESPREAD SNOW SHOWER ACTIVITY ACROSS MUCH OF THE BERING SEA AND
ALEUTIANS. MEANWHILE...A MATURE STORM NEAR THE KAMCHATKA PENINSULA
OF RUSSIA IS SLINGING A FRONT TOWARD THE WESTERN ALEUTIANS WITH
WINDS AT SHEMYA ALREADY BEGINNING TO INCREASE OUT OF THE SOUTH.

&&

.MODEL DISCUSSION...
THE MODELS REMAIN IN GOOD SYNOPTIC AGREEMENT...BUT CONTINUE TO
STRUGGLE IMMENSELY WITH THE DETAILS OF THE EVOLUTION IN THE GULF
AND ACROSS SOUTHCENTRAL DURING THE NEXT 24-36 HOURS. THE MAIN
PLAYERS ARE THE COLD AIR ALOFT MOVING IN FROM THE SOUTH THAT WILL
FURTHER DESTABILIZE THE ATMOSPHERE AND GIVE AN EXTRA SHOT IN THE
ARM TO SNOW SHOWER ACTIVITY. THANKFULLY THIS IS A BROAD-SCALE
FEATURE AND IS HIGH CONFIDENCE. MUCH LOWER CONFIDENCE ARE THE
MOVEMENT AND STRENGTH OF THE SHORTWAVE MOVING NORTHWARD NEAR
KODIAK ISLAND AS WELL AS THE ABILITY OF ANY LOCALIZED AREAS OF
CONVERGENCE TO FOCUS THIS CONVECTION (FOR EXAMPLE NEAR WESTERN
TURNAGAIN ARM). THE BOTTOM LINE TODAY IS THAT THE SUBTLE DETAILS
IN THE ATMOSPHERE WILL LIKELY PLAY AN EVEN BIGGER ROLE THAN
NORMAL IN DETERMINING WHERE AND HOW MUCH SNOW FALLS ACROSS
SOUTHCENTRAL ALASKA OVER THE NEXT 2 DAYS...AND OUT OF NECESSITY A
MORE BROAD- BRUSHED APPROACH WILL BE EMPLOYED AND RADAR AND
SATELLITE TRENDS WILL BE MONITORED CLOSELY UNTIL SUCH A TIME AS
THE ATMOSPHERE TIPS ITS HAND ABOUT WHAT WILL HAPPEN. AS YOU CAN
IMAGINE...FORECAST CONFIDENCE IS BELOW AVERAGE ACROSS SOUTHCENTRAL
ALASKA.

OUT WEST...THE DEVELOPMENT OF A STRONG LOW IN THE WESTERN BERING
EARLY NEXT WEEK IS BECOMING THE PRIMARY FORECAST CHALLENGE. THE
GFS CONTINUES TO BE FURTHER WEST THAN THE REST OF THE GLOBAL
GUIDANCE...AND WITH GOOD RUN-TO-RUN CONSISTENCY OF THE
ECMWF...WILL TREND THE FORECAST THAT DIRECTION. THE PRIMARY THREAT
WILL BE THE POTENTIAL FOR HIGH WINDS IN THE WESTERN ALEUTIANS AS
THE LOW REACHES PEAK INTENSITY TUESDAY MORNING.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT TWO DAYS.
THE FLOW REGIME DOES NOT CHANGE MUCH AT ALL. COLDER AND MORE
UNSTABLE AIR ALOFT MOVES OVERHEAD FROM THE GULF AND WILL BE THE
FOCUS FOR SNOW SHOWERS ACROSS MUCH OF THE REGION. SHOWERS WILL BE
ENHANCED BY A DISTURBANCE ALOFT...CURRENTLY SITTING IN THE CENTRAL
GULF...AS IT MOVES NORTHWARD LATE TONIGHT INTO TOMORROW MORNING.
INSTABILITY WILL REMAIN OVER THE AREA THROUGH LATE TOMORROW NIGHT
BEFORE THE FLOW BEGINS TO STABILIZE INTO MID-WEEK. ACCUMULATIONS
WILL GENERALLY REMAIN LIGHT BUT COULD ADD UP FAST FOR ANY AREA
WHERE BANDING SITS OVERHEAD FOR A PROLONGED PERIOD OF TIME. FOR
THE MOST PART ANY SHOWERY ACTIVITY SHOULD STAY AS OPEN CELLED IN
NATURE BUT SOME BANDING FROM LOW LEVEL CONVERGENCE ALONG TURNAGAIN
ARM IS NOT OUT OF THE QUESTION.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

NORTHERLY FLOW IN COLD ADVECTION REGIME WILL CONTINUE THROUGH
MONDAY. MODELS DEPICT ENOUGH LOW LEVEL MOISTURE IN THE LOWEST 1K
FEET WHERE SHELTERED AREAS OF SOUTHWEST ALASKA WILL BE CAPABLE OF
DEVELOPING SOME PATCHY FOG...AS HAS OCCURRED TODAY IN PARTS OF THE
KUSKOKWIM VALLEY AND BRISTOL BAY. EXCEPT FOR THE OUTER COAST OF
THE KUSKOKWIM DELTA OUTER COASTLINE TONIGHT...AND ALONG THE ALASKA
AND ALEUTIAN RANGES...PRECIPITATION CHANCES WILL BE ZERO.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

TRANQUIL CONDITIONS BY BERING SEA STANDARDS THE NEXT DAY OR SO
WITH A MINOR DISTURBANCE BRINGING SOME LIKELY RAIN AND SNOW TO
THE WESTERN ALEUTIANS TONIGHT INTO SUNDAY.

THE SYSTEM TO WATCH WILL BEGIN TO MAKE ITS PRESENCE FELT MONDAY
INTO TUESDAY AS A LOW MOVES ACROSS THE WESTERN ALEUTIANS AND INTO
THE WESTERN BERING SEA. THE EUROPEAN (AND TO A LESSER EXTENT THE
GLOBAL CANADIAN) MODEL IS PREFERRED WITH ITS MORE ELONGATED
CIRCULATION ALONG ITS ASSOCIATED WEATHER FRONT. THE GFS (WITH SOME
SUPPORT FROM THE NAM) KEEPS THE LOW A BIT MORE WEST OF THE
EUROPEAN AND CANADIAN MODELS BUT ALSO MORE ANNULAR. REGARDLESS OF
WHICH MODEL IS CORRECT...WITH THE FORECASTED INTENSIFICATION OF
THE LOW THERE IS AN INCREASING LIKELIHOOD OF POWERFUL WESTERLY
WINDS WRAPPING AROUND THE BACKSIDE OF THE LOW OVER THE WESTERN
ALEUTIANS AND NEARBY COASTAL WATERS. IF THE EUROPEAN IS
CORRECT...A THREAT OF THESE STRONGER WINDS COULD ALSO REACH THE
CENTRAL ALEUTIANS AND ITS NEARBY COASTAL WATERS.

THE PRECEDING WEATHER FRONT WILL ALSO CARRY A SWATH OF STRONG
WINDS TO STORM-FORCE ALONG AND JUST AHEAD OF THE FRONT AS IT RACES
ACROSS THE BERING SEA...INTENSIFYING OVER THE SOUTHERN AND WESTERN
BERING MONDAY NIGHT AND REACHING THE PRIBILOFS AND EASTERN
ALEUTIANS DURING THE DAY ON TUESDAY. THE FASTER EC WAS ALSO
PREFERRED OVER THE SLOWER GFS WITH PROGRESSION OF THE FRONT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
AN ACTIVE JET STREAM KEEPS THE WEATHER PATTERN IN MOTION THROUGH
NEXT WEEKEND. MODELS ARE FINALLY STARTING TO COME INTO BETTER SYNOPTIC
AGREEMENT WITH A CLOSED LOW CENTER DEVELOPING TUESDAY NIGHT IN THE
WESTERN BERING AS A LONGWAVE SHIFTS EAST FROM THE KAMCHATKA
PENINSULA. THIS LOW PRESSURE SYSTEM AND A POLAR LOW IN THE ARCTIC
FORCES THE WEAK UPPER TROUGH...CURRENTLY OVER THE GULF OF
ALASKA...TOWARD SOUTHEAST ALASKA MID WEEK. THE PATTERN FOR THE
WEEK AHEAD WILL MAINLY BE DRIVEN BY THE LOW IN THE WESTERN
BERING...HOWEVER THE POLAR LOW WILL PUSH A FRONT FROM THE
NORTHWEST COAST TO THE SOUTHERN MAINLAND WEDNESDAY. THE SHORTWAVES
FROM THESE TWO SYSTEMS WILL BRING SNOW SHOWERS WITH GUSTY WINDS
MAINLY ALONG THE QUICKLY DEVELOPING LOW PRESSURE SYSTEMS DRIVEN
FROM THE BERING LOW. MODEL CONFIDENCE IS LOWER THAN AVERAGE ON THE
UPCOMING SHORTWAVES AND THUS CHANGES IN LONG RANGE FORECAST
PRECIPITATION AND WINDS CAN BE EXPECTED.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM 178.
         GALES 170 172 173 174 175 176 177 185 411 412 413 414
         HEAVY FREEZING SPRAY...180 181.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...KH



000
FXAK68 PAFC 220119
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
419 PM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...
AN UPPER LEVEL TROUGH EXTENDS FROM THE WEST COAST OF ALASKA SOUTHWARD
INTO THE NORTH PACIFIC. THE JET REMAINS LARGELY SUPPRESSED WELL
SOUTH OF MAINLAND ALASKA...WITH A 200 KT JET EXITING ASIA AND
HEADING INTO THE LONGWAVE TROUGH AND A 180 KT JET COMING OUT OF
THE TROUGH AND SLAMMING INTO THE SOUTHERN PANHANDLE. A DECAYING
VERTICALLY STACKED LOW IN THE WESTERN GULF IS SLOWLY LIFTING
NORTHWARD WITH NUMEROUS EMBEDDED FEATURES AT THE SURFACE AND ALSO
ALOFT. THIS IS LEADING TO A MORE SHOWERY PATTERN ACROSS SOUTHERN
ALASKA THAN HAS BEEN SEEN RECENTLY. A MORE FOCUSED BAND OF
CONVECTIVE SNOW SHOWERS IS PERSISTING FROM WESTERN PRINCE WILLIAM
SOUND UP TO EAGLE RIVER AND INTO THE SUSITNA VALLEY. SNOWFALL
TOTALS HAVE RANGED FROM 4-7 INCHES NEAR PORTAGE TO UPWARDS OF 2 INCHES
ON THE WEST SIDE OF THE MOUNTAINS. THERE IS ANOTHER WEAK
CIRCULATION EAST OF KODIAK ISLAND HEADING NORTHWARD...WITH
INCREASING SHOWER ACTIVITY ALREADY DEVELOPING ACROSS MUCH OF THE
GULF OF ALASKA AS THIS LOW TEAMS UP WITH COLDER AIR MOVING IN AT
500 MB TO STEEPEN LAPSE RATES ACROSS A LARGE SECTION OF THE GULF.

OUT WEST...WEAK HIGH PRESSURE AND NORTHERLY FLOW ARE ALLOWING
COLD AIR TO STREAM SOUTHWARD FROM THE BERING STRAIT AND PRODUCE
WIDESPREAD SNOW SHOWER ACTIVITY ACROSS MUCH OF THE BERING SEA AND
ALEUTIANS. MEANWHILE...A MATURE STORM NEAR THE KAMCHATKA PENINSULA
OF RUSSIA IS SLINGING A FRONT TOWARD THE WESTERN ALEUTIANS WITH
WINDS AT SHEMYA ALREADY BEGINNING TO INCREASE OUT OF THE SOUTH.

&&

.MODEL DISCUSSION...
THE MODELS REMAIN IN GOOD SYNOPTIC AGREEMENT...BUT CONTINUE TO
STRUGGLE IMMENSELY WITH THE DETAILS OF THE EVOLUTION IN THE GULF
AND ACROSS SOUTHCENTRAL DURING THE NEXT 24-36 HOURS. THE MAIN
PLAYERS ARE THE COLD AIR ALOFT MOVING IN FROM THE SOUTH THAT WILL
FURTHER DESTABILIZE THE ATMOSPHERE AND GIVE AN EXTRA SHOT IN THE
ARM TO SNOW SHOWER ACTIVITY. THANKFULLY THIS IS A BROAD-SCALE
FEATURE AND IS HIGH CONFIDENCE. MUCH LOWER CONFIDENCE ARE THE
MOVEMENT AND STRENGTH OF THE SHORTWAVE MOVING NORTHWARD NEAR
KODIAK ISLAND AS WELL AS THE ABILITY OF ANY LOCALIZED AREAS OF
CONVERGENCE TO FOCUS THIS CONVECTION (FOR EXAMPLE NEAR WESTERN
TURNAGAIN ARM). THE BOTTOM LINE TODAY IS THAT THE SUBTLE DETAILS
IN THE ATMOSPHERE WILL LIKELY PLAY AN EVEN BIGGER ROLE THAN
NORMAL IN DETERMINING WHERE AND HOW MUCH SNOW FALLS ACROSS
SOUTHCENTRAL ALASKA OVER THE NEXT 2 DAYS...AND OUT OF NECESSITY A
MORE BROAD- BRUSHED APPROACH WILL BE EMPLOYED AND RADAR AND
SATELLITE TRENDS WILL BE MONITORED CLOSELY UNTIL SUCH A TIME AS
THE ATMOSPHERE TIPS ITS HAND ABOUT WHAT WILL HAPPEN. AS YOU CAN
IMAGINE...FORECAST CONFIDENCE IS BELOW AVERAGE ACROSS SOUTHCENTRAL
ALASKA.

OUT WEST...THE DEVELOPMENT OF A STRONG LOW IN THE WESTERN BERING
EARLY NEXT WEEK IS BECOMING THE PRIMARY FORECAST CHALLENGE. THE
GFS CONTINUES TO BE FURTHER WEST THAN THE REST OF THE GLOBAL
GUIDANCE...AND WITH GOOD RUN-TO-RUN CONSISTENCY OF THE
ECMWF...WILL TREND THE FORECAST THAT DIRECTION. THE PRIMARY THREAT
WILL BE THE POTENTIAL FOR HIGH WINDS IN THE WESTERN ALEUTIANS AS
THE LOW REACHES PEAK INTENSITY TUESDAY MORNING.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
THE FORECAST REMAINS PRETTY LOW CONFIDENCE OVER THE NEXT TWO DAYS.
THE FLOW REGIME DOES NOT CHANGE MUCH AT ALL. COLDER AND MORE
UNSTABLE AIR ALOFT MOVES OVERHEAD FROM THE GULF AND WILL BE THE
FOCUS FOR SNOW SHOWERS ACROSS MUCH OF THE REGION. SHOWERS WILL BE
ENHANCED BY A DISTURBANCE ALOFT...CURRENTLY SITTING IN THE CENTRAL
GULF...AS IT MOVES NORTHWARD LATE TONIGHT INTO TOMORROW MORNING.
INSTABILITY WILL REMAIN OVER THE AREA THROUGH LATE TOMORROW NIGHT
BEFORE THE FLOW BEGINS TO STABILIZE INTO MID-WEEK. ACCUMULATIONS
WILL GENERALLY REMAIN LIGHT BUT COULD ADD UP FAST FOR ANY AREA
WHERE BANDING SITS OVERHEAD FOR A PROLONGED PERIOD OF TIME. FOR
THE MOST PART ANY SHOWERY ACTIVITY SHOULD STAY AS OPEN CELLED IN
NATURE BUT SOME BANDING FROM LOW LEVEL CONVERGENCE ALONG TURNAGAIN
ARM IS NOT OUT OF THE QUESTION.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

NORTHERLY FLOW IN COLD ADVECTION REGIME WILL CONTINUE THROUGH
MONDAY. MODELS DEPICT ENOUGH LOW LEVEL MOISTURE IN THE LOWEST 1K
FEET WHERE SHELTERED AREAS OF SOUTHWEST ALASKA WILL BE CAPABLE OF
DEVELOPING SOME PATCHY FOG...AS HAS OCCURRED TODAY IN PARTS OF THE
KUSKOKWIM VALLEY AND BRISTOL BAY. EXCEPT FOR THE OUTER COAST OF
THE KUSKOKWIM DELTA OUTER COASTLINE TONIGHT...AND ALONG THE ALASKA
AND ALEUTIAN RANGES...PRECIPITATION CHANCES WILL BE ZERO.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

TRANQUIL CONDITIONS BY BERING SEA STANDARDS THE NEXT DAY OR SO
WITH A MINOR DISTURBANCE BRINGING SOME LIKELY RAIN AND SNOW TO
THE WESTERN ALEUTIANS TONIGHT INTO SUNDAY.

THE SYSTEM TO WATCH WILL BEGIN TO MAKE ITS PRESENCE FELT MONDAY
INTO TUESDAY AS A LOW MOVES ACROSS THE WESTERN ALEUTIANS AND INTO
THE WESTERN BERING SEA. THE EUROPEAN (AND TO A LESSER EXTENT THE
GLOBAL CANADIAN) MODEL IS PREFERRED WITH ITS MORE ELONGATED
CIRCULATION ALONG ITS ASSOCIATED WEATHER FRONT. THE GFS (WITH SOME
SUPPORT FROM THE NAM) KEEPS THE LOW A BIT MORE WEST OF THE
EUROPEAN AND CANADIAN MODELS BUT ALSO MORE ANNULAR. REGARDLESS OF
WHICH MODEL IS CORRECT...WITH THE FORECASTED INTENSIFICATION OF
THE LOW THERE IS AN INCREASING LIKELIHOOD OF POWERFUL WESTERLY
WINDS WRAPPING AROUND THE BACKSIDE OF THE LOW OVER THE WESTERN
ALEUTIANS AND NEARBY COASTAL WATERS. IF THE EUROPEAN IS
CORRECT...A THREAT OF THESE STRONGER WINDS COULD ALSO REACH THE
CENTRAL ALEUTIANS AND ITS NEARBY COASTAL WATERS.

THE PRECEDING WEATHER FRONT WILL ALSO CARRY A SWATH OF STRONG
WINDS TO STORM-FORCE ALONG AND JUST AHEAD OF THE FRONT AS IT RACES
ACROSS THE BERING SEA...INTENSIFYING OVER THE SOUTHERN AND WESTERN
BERING MONDAY NIGHT AND REACHING THE PRIBILOFS AND EASTERN
ALEUTIANS DURING THE DAY ON TUESDAY. THE FASTER EC WAS ALSO
PREFERRED OVER THE SLOWER GFS WITH PROGRESSION OF THE FRONT.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
AN ACTIVE JET STREAM KEEPS THE WEATHER PATTERN IN MOTION THROUGH
NEXT WEEKEND. MODELS ARE FINALLY STARTING TO COME INTO BETTER SYNOPTIC
AGREEMENT WITH A CLOSED LOW CENTER DEVELOPING TUESDAY NIGHT IN THE
WESTERN BERING AS A LONGWAVE SHIFTS EAST FROM THE KAMCHATKA
PENINSULA. THIS LOW PRESSURE SYSTEM AND A POLAR LOW IN THE ARCTIC
FORCES THE WEAK UPPER TROUGH...CURRENTLY OVER THE GULF OF
ALASKA...TOWARD SOUTHEAST ALASKA MID WEEK. THE PATTERN FOR THE
WEEK AHEAD WILL MAINLY BE DRIVEN BY THE LOW IN THE WESTERN
BERING...HOWEVER THE POLAR LOW WILL PUSH A FRONT FROM THE
NORTHWEST COAST TO THE SOUTHERN MAINLAND WEDNESDAY. THE SHORTWAVES
FROM THESE TWO SYSTEMS WILL BRING SNOW SHOWERS WITH GUSTY WINDS
MAINLY ALONG THE QUICKLY DEVELOPING LOW PRESSURE SYSTEMS DRIVEN
FROM THE BERING LOW. MODEL CONFIDENCE IS LOWER THAN AVERAGE ON THE
UPCOMING SHORTWAVES AND THUS CHANGES IN LONG RANGE FORECAST
PRECIPITATION AND WINDS CAN BE EXPECTED.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...STORM 178.
         GALES 170 172 173 174 175 176 177 185 411 412 413 414
         HEAVY FREEZING SPRAY...180 181.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...CC
LONG TERM...KH




000
FXAK67 PAJK 220050
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
350 PM AKST SUN DEC 21 2014

.SHORT TERM.../ SUNDAY NIGHT AND MONDAY / NO LARGE SCALE FEATURES
ACROSS SOUTHEAST ALASKA THIS EVENING ON SATELLITE IMAGERY. CAN SPOT
THE JET STREAM FLOWING ACROSS THE PACIFIC TO THE WASHINGTON AND
OREGON COAST AND THE START OF THE BAROCLINIC LEAF THAT WILL BECOME
A WEATHER MAKER FOR THE AREA LATE MONDAY.

IN THE MEAN TIME THERE IS ROUGHLY ONE TROUGH OF SHOWERS LIFTING
SLOWLY NORTHWARD INTO THE NORTHERN PANHANDLE THROUGH LATE
AFTERNOON AND EVENING. CONDITIONS ACROSS THE SOUTHERN PANHANDLE
STARTED TO BREAK OUT ON WEB CAMS AND OBSERVATIONS THROUGH THE
EVENING HOWEVER WEAK ONSHORE FLOW WILL CONTINUE TO PUSH SCATTERED
SHOWER ACTIVITY INTO THE NORTHERN PANHANDLE. EXPECT A BREAK AGAIN
ON MONDAY IN ADVANCE OF THE NEXT SYSTEM.

ACROSS THE CENTRAL AND NORTHERN PANHANDLE SHOWERS EXITING ARE LEADING
TO A BREAK IN THE DEVELOPMENT AS THE SHOWERS TRY TO MOVE NORTHWARD
TODAY. CHANCE TO LIKELY POPS FOR MUCH OF THIS AREA...BUT AMOUNTS
SHOULD BE GENERALLY LIGHT. NORTHERN PANHANDLE WILL PERSIST WITH
PRECIPITATION TYPE ISSUES. SNOW AGGRESSIVELY HANGING ON FROM
HAINES AND SKAGWAY NORTHWARD. ALSO STILL SOME ISOLATED SNOW OVER
THE DEEP INLAND VALLEYS AROUND JUNEAU. OTHERWISE PRECIPITATION
SHOULD BE RAIN. BEST SNOW AMOUNTS OVER NORTHERN LYNN CANAL ZONES
BUT AMOUNTS UNDER 2 INCHES SHOULD BE EXPECTED.

NO BIG WARNINGS OR ADVISORIES OTHER THAN SOME SMALL CRAFT IN THE
MARINE FORECASTS. WITH WINTER SOLSTICE THIS AFTERNOON DAYS WILL
SLOWLY INCREASE NOW. CONFIDENCE THROUGH THE SHORT TERM IS
SLIGHTLY ABOVE AVERAGE THROUGH MONDAY.

.LONG TERM...LATEST MODEL RUNS HAVE STAYED CONSISTENT IN TRACKING
THE LOW PRESSURE SYSTEM MONDAY NIGHT AND TUESDAY ACROSS THE FAR
SOUTHERN PANHANDLE. LOOKING AT LATEST GUIDANCE AND PREVIOUS
FORECAST DECIDED TO LEAVE MOST OF IT AS IS FOR THIS STORM SYSTEM.
STILL EXPECTING GALE FORCE SOUTHEASTERLY WINDS IN THE SOUTHEAST
GULF AND SOUTHERN INNER CHANNELS. STRONG NORTHERLY PRESSURE
GRADIENT OVER THE NORTHERN PANHANDLE WILL DEVELOP MONDAY NIGHT AS
THIS LOW TRACKS INTO THE AREA WITH GALE FORCE WINDS DEVELOPING
THERE. STRONG WIND HEADLINES WILL LIKELY BE NEEDED FOR THE
SOUTHERN PANHANDLE WITH GUSTS OF 40 TO 50 MPH ON TUESDAY. WITH THE
FARTHER SOUTHERN TRACK EXPECT THE STRONGEST WINDS WILL STAY SOUTH
AND MAINLY IMPACT THE HAIDA GWAII AREA. STRONG OFFSHORE FLOW WILL
KEEP PRECIPITATION MAINLY CONFINED TO SOUTH OF FREDERICK SOUND.
THE NORTHERLY WINDS WILL ALSO HELP TO USHER IN A BIT COOLER AIR
TO THE NORTHERN PANHANDLE.

THE LOW WEAKENS AND PULLS INTO BRITISH COLUMBIA ON TUESDAY NIGHT.
WEAK SURFACE RIDGING DEVELOPS OVER THE GULF WITH MULTIPLE WEAK
SHORTWAVES MOVING OVER TOP OF IT INTO SOUTHEAST ALASKA WEDNESDAY
THROUGH FRIDAY. THINK THERE WILL BE A WEAK OVERRUNNING EVENT
WEDNESDAY INTO THURSDAY. AS FOR PRECIPITATION TYPE, 850 MB
TEMPERATURES FALL TO -6 TO -8 C BY THIS TIME AS A COOLER AIRMASS
MOVES INTO THE AREA FROM THE WEST. 1000-850 MB THICKNESS FALL TO
AROUND 1285 M AND LIGHT SURFACE WINDS SUGGEST PRECIPITATION OVER
THE NORTHERN PANHANDLE WOULD LIKELY BE IN THE FORM OF SNOW. AT
THIS TIME PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT. MODELS
ARE SUGGESTING A MORE ORGANIZED AREA OF PRECIPITATION WILL IMPACT
THE AREA LATE THURSDAY INTO FRIDAY.

AS MENTIONED BY THE PREVIOUS SHIFT, MODELS HAVE BACKED OFF THE
IDEA OF A BLOCKING RIDGE NEXT WEEKEND AND HAVE GONE TOWARDS A MORE
PROGRESSIVE PATTERN OVER THE AREA. HOWEVER, MODEL AGREEMENT ON
INDIVIDUAL FEATURES STILL REMAINS POOR IN THIS TIME FRAME.

OPTED TO MAKE ONLY MINOR CHANGES AS PREVIOUS FORECAST MATCHED UP
WELL WITH LATEST MODEL GUIDANCE. USED 12Z ECMWF FOR UPDATES
THROUGH DAY 4 THEN LATEST WPC GUIDANCE FOR THE REMAINDER OF THE
LONG TERM. FORECASTER CONFIDENCE IS INCREASING ON A MORE SOUTHERLY
TRACK OF THE LOW EARLY THIS WEEK INTO THE FAR SOUTHERN PANHANDLE.
CONFIDENCE DECREASES LATER IN THE WEEK WITH MODEL DISAGREEMENT
CONTINUING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU






000
FXAK67 PAJK 220050
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
350 PM AKST SUN DEC 21 2014

.SHORT TERM.../ SUNDAY NIGHT AND MONDAY / NO LARGE SCALE FEATURES
ACROSS SOUTHEAST ALASKA THIS EVENING ON SATELLITE IMAGERY. CAN SPOT
THE JET STREAM FLOWING ACROSS THE PACIFIC TO THE WASHINGTON AND
OREGON COAST AND THE START OF THE BAROCLINIC LEAF THAT WILL BECOME
A WEATHER MAKER FOR THE AREA LATE MONDAY.

IN THE MEAN TIME THERE IS ROUGHLY ONE TROUGH OF SHOWERS LIFTING
SLOWLY NORTHWARD INTO THE NORTHERN PANHANDLE THROUGH LATE
AFTERNOON AND EVENING. CONDITIONS ACROSS THE SOUTHERN PANHANDLE
STARTED TO BREAK OUT ON WEB CAMS AND OBSERVATIONS THROUGH THE
EVENING HOWEVER WEAK ONSHORE FLOW WILL CONTINUE TO PUSH SCATTERED
SHOWER ACTIVITY INTO THE NORTHERN PANHANDLE. EXPECT A BREAK AGAIN
ON MONDAY IN ADVANCE OF THE NEXT SYSTEM.

ACROSS THE CENTRAL AND NORTHERN PANHANDLE SHOWERS EXITING ARE LEADING
TO A BREAK IN THE DEVELOPMENT AS THE SHOWERS TRY TO MOVE NORTHWARD
TODAY. CHANCE TO LIKELY POPS FOR MUCH OF THIS AREA...BUT AMOUNTS
SHOULD BE GENERALLY LIGHT. NORTHERN PANHANDLE WILL PERSIST WITH
PRECIPITATION TYPE ISSUES. SNOW AGGRESSIVELY HANGING ON FROM
HAINES AND SKAGWAY NORTHWARD. ALSO STILL SOME ISOLATED SNOW OVER
THE DEEP INLAND VALLEYS AROUND JUNEAU. OTHERWISE PRECIPITATION
SHOULD BE RAIN. BEST SNOW AMOUNTS OVER NORTHERN LYNN CANAL ZONES
BUT AMOUNTS UNDER 2 INCHES SHOULD BE EXPECTED.

NO BIG WARNINGS OR ADVISORIES OTHER THAN SOME SMALL CRAFT IN THE
MARINE FORECASTS. WITH WINTER SOLSTICE THIS AFTERNOON DAYS WILL
SLOWLY INCREASE NOW. CONFIDENCE THROUGH THE SHORT TERM IS
SLIGHTLY ABOVE AVERAGE THROUGH MONDAY.

.LONG TERM...LATEST MODEL RUNS HAVE STAYED CONSISTENT IN TRACKING
THE LOW PRESSURE SYSTEM MONDAY NIGHT AND TUESDAY ACROSS THE FAR
SOUTHERN PANHANDLE. LOOKING AT LATEST GUIDANCE AND PREVIOUS
FORECAST DECIDED TO LEAVE MOST OF IT AS IS FOR THIS STORM SYSTEM.
STILL EXPECTING GALE FORCE SOUTHEASTERLY WINDS IN THE SOUTHEAST
GULF AND SOUTHERN INNER CHANNELS. STRONG NORTHERLY PRESSURE
GRADIENT OVER THE NORTHERN PANHANDLE WILL DEVELOP MONDAY NIGHT AS
THIS LOW TRACKS INTO THE AREA WITH GALE FORCE WINDS DEVELOPING
THERE. STRONG WIND HEADLINES WILL LIKELY BE NEEDED FOR THE
SOUTHERN PANHANDLE WITH GUSTS OF 40 TO 50 MPH ON TUESDAY. WITH THE
FARTHER SOUTHERN TRACK EXPECT THE STRONGEST WINDS WILL STAY SOUTH
AND MAINLY IMPACT THE HAIDA GWAII AREA. STRONG OFFSHORE FLOW WILL
KEEP PRECIPITATION MAINLY CONFINED TO SOUTH OF FREDERICK SOUND.
THE NORTHERLY WINDS WILL ALSO HELP TO USHER IN A BIT COOLER AIR
TO THE NORTHERN PANHANDLE.

THE LOW WEAKENS AND PULLS INTO BRITISH COLUMBIA ON TUESDAY NIGHT.
WEAK SURFACE RIDGING DEVELOPS OVER THE GULF WITH MULTIPLE WEAK
SHORTWAVES MOVING OVER TOP OF IT INTO SOUTHEAST ALASKA WEDNESDAY
THROUGH FRIDAY. THINK THERE WILL BE A WEAK OVERRUNNING EVENT
WEDNESDAY INTO THURSDAY. AS FOR PRECIPITATION TYPE, 850 MB
TEMPERATURES FALL TO -6 TO -8 C BY THIS TIME AS A COOLER AIRMASS
MOVES INTO THE AREA FROM THE WEST. 1000-850 MB THICKNESS FALL TO
AROUND 1285 M AND LIGHT SURFACE WINDS SUGGEST PRECIPITATION OVER
THE NORTHERN PANHANDLE WOULD LIKELY BE IN THE FORM OF SNOW. AT
THIS TIME PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT. MODELS
ARE SUGGESTING A MORE ORGANIZED AREA OF PRECIPITATION WILL IMPACT
THE AREA LATE THURSDAY INTO FRIDAY.

AS MENTIONED BY THE PREVIOUS SHIFT, MODELS HAVE BACKED OFF THE
IDEA OF A BLOCKING RIDGE NEXT WEEKEND AND HAVE GONE TOWARDS A MORE
PROGRESSIVE PATTERN OVER THE AREA. HOWEVER, MODEL AGREEMENT ON
INDIVIDUAL FEATURES STILL REMAINS POOR IN THIS TIME FRAME.

OPTED TO MAKE ONLY MINOR CHANGES AS PREVIOUS FORECAST MATCHED UP
WELL WITH LATEST MODEL GUIDANCE. USED 12Z ECMWF FOR UPDATES
THROUGH DAY 4 THEN LATEST WPC GUIDANCE FOR THE REMAINDER OF THE
LONG TERM. FORECASTER CONFIDENCE IS INCREASING ON A MORE SOUTHERLY
TRACK OF THE LOW EARLY THIS WEEK INTO THE FAR SOUTHERN PANHANDLE.
CONFIDENCE DECREASES LATER IN THE WEEK WITH MODEL DISAGREEMENT
CONTINUING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK67 PAJK 220050
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
350 PM AKST SUN DEC 21 2014

.SHORT TERM.../ SUNDAY NIGHT AND MONDAY / NO LARGE SCALE FEATURES
ACROSS SOUTHEAST ALASKA THIS EVENING ON SATELLITE IMAGERY. CAN SPOT
THE JET STREAM FLOWING ACROSS THE PACIFIC TO THE WASHINGTON AND
OREGON COAST AND THE START OF THE BAROCLINIC LEAF THAT WILL BECOME
A WEATHER MAKER FOR THE AREA LATE MONDAY.

IN THE MEAN TIME THERE IS ROUGHLY ONE TROUGH OF SHOWERS LIFTING
SLOWLY NORTHWARD INTO THE NORTHERN PANHANDLE THROUGH LATE
AFTERNOON AND EVENING. CONDITIONS ACROSS THE SOUTHERN PANHANDLE
STARTED TO BREAK OUT ON WEB CAMS AND OBSERVATIONS THROUGH THE
EVENING HOWEVER WEAK ONSHORE FLOW WILL CONTINUE TO PUSH SCATTERED
SHOWER ACTIVITY INTO THE NORTHERN PANHANDLE. EXPECT A BREAK AGAIN
ON MONDAY IN ADVANCE OF THE NEXT SYSTEM.

ACROSS THE CENTRAL AND NORTHERN PANHANDLE SHOWERS EXITING ARE LEADING
TO A BREAK IN THE DEVELOPMENT AS THE SHOWERS TRY TO MOVE NORTHWARD
TODAY. CHANCE TO LIKELY POPS FOR MUCH OF THIS AREA...BUT AMOUNTS
SHOULD BE GENERALLY LIGHT. NORTHERN PANHANDLE WILL PERSIST WITH
PRECIPITATION TYPE ISSUES. SNOW AGGRESSIVELY HANGING ON FROM
HAINES AND SKAGWAY NORTHWARD. ALSO STILL SOME ISOLATED SNOW OVER
THE DEEP INLAND VALLEYS AROUND JUNEAU. OTHERWISE PRECIPITATION
SHOULD BE RAIN. BEST SNOW AMOUNTS OVER NORTHERN LYNN CANAL ZONES
BUT AMOUNTS UNDER 2 INCHES SHOULD BE EXPECTED.

NO BIG WARNINGS OR ADVISORIES OTHER THAN SOME SMALL CRAFT IN THE
MARINE FORECASTS. WITH WINTER SOLSTICE THIS AFTERNOON DAYS WILL
SLOWLY INCREASE NOW. CONFIDENCE THROUGH THE SHORT TERM IS
SLIGHTLY ABOVE AVERAGE THROUGH MONDAY.

.LONG TERM...LATEST MODEL RUNS HAVE STAYED CONSISTENT IN TRACKING
THE LOW PRESSURE SYSTEM MONDAY NIGHT AND TUESDAY ACROSS THE FAR
SOUTHERN PANHANDLE. LOOKING AT LATEST GUIDANCE AND PREVIOUS
FORECAST DECIDED TO LEAVE MOST OF IT AS IS FOR THIS STORM SYSTEM.
STILL EXPECTING GALE FORCE SOUTHEASTERLY WINDS IN THE SOUTHEAST
GULF AND SOUTHERN INNER CHANNELS. STRONG NORTHERLY PRESSURE
GRADIENT OVER THE NORTHERN PANHANDLE WILL DEVELOP MONDAY NIGHT AS
THIS LOW TRACKS INTO THE AREA WITH GALE FORCE WINDS DEVELOPING
THERE. STRONG WIND HEADLINES WILL LIKELY BE NEEDED FOR THE
SOUTHERN PANHANDLE WITH GUSTS OF 40 TO 50 MPH ON TUESDAY. WITH THE
FARTHER SOUTHERN TRACK EXPECT THE STRONGEST WINDS WILL STAY SOUTH
AND MAINLY IMPACT THE HAIDA GWAII AREA. STRONG OFFSHORE FLOW WILL
KEEP PRECIPITATION MAINLY CONFINED TO SOUTH OF FREDERICK SOUND.
THE NORTHERLY WINDS WILL ALSO HELP TO USHER IN A BIT COOLER AIR
TO THE NORTHERN PANHANDLE.

THE LOW WEAKENS AND PULLS INTO BRITISH COLUMBIA ON TUESDAY NIGHT.
WEAK SURFACE RIDGING DEVELOPS OVER THE GULF WITH MULTIPLE WEAK
SHORTWAVES MOVING OVER TOP OF IT INTO SOUTHEAST ALASKA WEDNESDAY
THROUGH FRIDAY. THINK THERE WILL BE A WEAK OVERRUNNING EVENT
WEDNESDAY INTO THURSDAY. AS FOR PRECIPITATION TYPE, 850 MB
TEMPERATURES FALL TO -6 TO -8 C BY THIS TIME AS A COOLER AIRMASS
MOVES INTO THE AREA FROM THE WEST. 1000-850 MB THICKNESS FALL TO
AROUND 1285 M AND LIGHT SURFACE WINDS SUGGEST PRECIPITATION OVER
THE NORTHERN PANHANDLE WOULD LIKELY BE IN THE FORM OF SNOW. AT
THIS TIME PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT. MODELS
ARE SUGGESTING A MORE ORGANIZED AREA OF PRECIPITATION WILL IMPACT
THE AREA LATE THURSDAY INTO FRIDAY.

AS MENTIONED BY THE PREVIOUS SHIFT, MODELS HAVE BACKED OFF THE
IDEA OF A BLOCKING RIDGE NEXT WEEKEND AND HAVE GONE TOWARDS A MORE
PROGRESSIVE PATTERN OVER THE AREA. HOWEVER, MODEL AGREEMENT ON
INDIVIDUAL FEATURES STILL REMAINS POOR IN THIS TIME FRAME.

OPTED TO MAKE ONLY MINOR CHANGES AS PREVIOUS FORECAST MATCHED UP
WELL WITH LATEST MODEL GUIDANCE. USED 12Z ECMWF FOR UPDATES
THROUGH DAY 4 THEN LATEST WPC GUIDANCE FOR THE REMAINDER OF THE
LONG TERM. FORECASTER CONFIDENCE IS INCREASING ON A MORE SOUTHERLY
TRACK OF THE LOW EARLY THIS WEEK INTO THE FAR SOUTHERN PANHANDLE.
CONFIDENCE DECREASES LATER IN THE WEEK WITH MODEL DISAGREEMENT
CONTINUING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU






000
FXAK67 PAJK 220050
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
350 PM AKST SUN DEC 21 2014

.SHORT TERM.../ SUNDAY NIGHT AND MONDAY / NO LARGE SCALE FEATURES
ACROSS SOUTHEAST ALASKA THIS EVENING ON SATELLITE IMAGERY. CAN SPOT
THE JET STREAM FLOWING ACROSS THE PACIFIC TO THE WASHINGTON AND
OREGON COAST AND THE START OF THE BAROCLINIC LEAF THAT WILL BECOME
A WEATHER MAKER FOR THE AREA LATE MONDAY.

IN THE MEAN TIME THERE IS ROUGHLY ONE TROUGH OF SHOWERS LIFTING
SLOWLY NORTHWARD INTO THE NORTHERN PANHANDLE THROUGH LATE
AFTERNOON AND EVENING. CONDITIONS ACROSS THE SOUTHERN PANHANDLE
STARTED TO BREAK OUT ON WEB CAMS AND OBSERVATIONS THROUGH THE
EVENING HOWEVER WEAK ONSHORE FLOW WILL CONTINUE TO PUSH SCATTERED
SHOWER ACTIVITY INTO THE NORTHERN PANHANDLE. EXPECT A BREAK AGAIN
ON MONDAY IN ADVANCE OF THE NEXT SYSTEM.

ACROSS THE CENTRAL AND NORTHERN PANHANDLE SHOWERS EXITING ARE LEADING
TO A BREAK IN THE DEVELOPMENT AS THE SHOWERS TRY TO MOVE NORTHWARD
TODAY. CHANCE TO LIKELY POPS FOR MUCH OF THIS AREA...BUT AMOUNTS
SHOULD BE GENERALLY LIGHT. NORTHERN PANHANDLE WILL PERSIST WITH
PRECIPITATION TYPE ISSUES. SNOW AGGRESSIVELY HANGING ON FROM
HAINES AND SKAGWAY NORTHWARD. ALSO STILL SOME ISOLATED SNOW OVER
THE DEEP INLAND VALLEYS AROUND JUNEAU. OTHERWISE PRECIPITATION
SHOULD BE RAIN. BEST SNOW AMOUNTS OVER NORTHERN LYNN CANAL ZONES
BUT AMOUNTS UNDER 2 INCHES SHOULD BE EXPECTED.

NO BIG WARNINGS OR ADVISORIES OTHER THAN SOME SMALL CRAFT IN THE
MARINE FORECASTS. WITH WINTER SOLSTICE THIS AFTERNOON DAYS WILL
SLOWLY INCREASE NOW. CONFIDENCE THROUGH THE SHORT TERM IS
SLIGHTLY ABOVE AVERAGE THROUGH MONDAY.

.LONG TERM...LATEST MODEL RUNS HAVE STAYED CONSISTENT IN TRACKING
THE LOW PRESSURE SYSTEM MONDAY NIGHT AND TUESDAY ACROSS THE FAR
SOUTHERN PANHANDLE. LOOKING AT LATEST GUIDANCE AND PREVIOUS
FORECAST DECIDED TO LEAVE MOST OF IT AS IS FOR THIS STORM SYSTEM.
STILL EXPECTING GALE FORCE SOUTHEASTERLY WINDS IN THE SOUTHEAST
GULF AND SOUTHERN INNER CHANNELS. STRONG NORTHERLY PRESSURE
GRADIENT OVER THE NORTHERN PANHANDLE WILL DEVELOP MONDAY NIGHT AS
THIS LOW TRACKS INTO THE AREA WITH GALE FORCE WINDS DEVELOPING
THERE. STRONG WIND HEADLINES WILL LIKELY BE NEEDED FOR THE
SOUTHERN PANHANDLE WITH GUSTS OF 40 TO 50 MPH ON TUESDAY. WITH THE
FARTHER SOUTHERN TRACK EXPECT THE STRONGEST WINDS WILL STAY SOUTH
AND MAINLY IMPACT THE HAIDA GWAII AREA. STRONG OFFSHORE FLOW WILL
KEEP PRECIPITATION MAINLY CONFINED TO SOUTH OF FREDERICK SOUND.
THE NORTHERLY WINDS WILL ALSO HELP TO USHER IN A BIT COOLER AIR
TO THE NORTHERN PANHANDLE.

THE LOW WEAKENS AND PULLS INTO BRITISH COLUMBIA ON TUESDAY NIGHT.
WEAK SURFACE RIDGING DEVELOPS OVER THE GULF WITH MULTIPLE WEAK
SHORTWAVES MOVING OVER TOP OF IT INTO SOUTHEAST ALASKA WEDNESDAY
THROUGH FRIDAY. THINK THERE WILL BE A WEAK OVERRUNNING EVENT
WEDNESDAY INTO THURSDAY. AS FOR PRECIPITATION TYPE, 850 MB
TEMPERATURES FALL TO -6 TO -8 C BY THIS TIME AS A COOLER AIRMASS
MOVES INTO THE AREA FROM THE WEST. 1000-850 MB THICKNESS FALL TO
AROUND 1285 M AND LIGHT SURFACE WINDS SUGGEST PRECIPITATION OVER
THE NORTHERN PANHANDLE WOULD LIKELY BE IN THE FORM OF SNOW. AT
THIS TIME PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT. MODELS
ARE SUGGESTING A MORE ORGANIZED AREA OF PRECIPITATION WILL IMPACT
THE AREA LATE THURSDAY INTO FRIDAY.

AS MENTIONED BY THE PREVIOUS SHIFT, MODELS HAVE BACKED OFF THE
IDEA OF A BLOCKING RIDGE NEXT WEEKEND AND HAVE GONE TOWARDS A MORE
PROGRESSIVE PATTERN OVER THE AREA. HOWEVER, MODEL AGREEMENT ON
INDIVIDUAL FEATURES STILL REMAINS POOR IN THIS TIME FRAME.

OPTED TO MAKE ONLY MINOR CHANGES AS PREVIOUS FORECAST MATCHED UP
WELL WITH LATEST MODEL GUIDANCE. USED 12Z ECMWF FOR UPDATES
THROUGH DAY 4 THEN LATEST WPC GUIDANCE FOR THE REMAINDER OF THE
LONG TERM. FORECASTER CONFIDENCE IS INCREASING ON A MORE SOUTHERLY
TRACK OF THE LOW EARLY THIS WEEK INTO THE FAR SOUTHERN PANHANDLE.
CONFIDENCE DECREASES LATER IN THE WEEK WITH MODEL DISAGREEMENT
CONTINUING.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ012-013-036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK69 PAFG 212211
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
111 PM AKST SUN DEC 21 2014

.DISCUSSION...

21/12Z DETERMINISTIC MODEL SUITE IS GENERALLY IN GOOD AGREEMENT
THROUGH 12Z TUESDAY WITH THE OVERALL SYNOPTIC PATTERN.
THEREAFTER...MODEL DIFFERENCES BETWEEN THE GFS AND ECWMF BECOME
APPARENT...WITH THE GFS PAINTING A MORE AMPLIFIED RIDGE ALOFT OVER
MAINLAND ALASKA AND SIGNIFICANT DIFFERENCES WITH THE SURFACE LOW
OVER THE BERING LATE THIS WEEK. USED A BLEND OF THE PREVIOUS
FORECAST AND MODEL BLEND THROUGH 00Z THURSDAY.

MAIN CONCERNS INCLUDE WINDS ALONG THE WEST COAST AND ST LAWRENCE
ISLAND AND FOG/LOW STRATUS DECK OVER THE ARCTIC COAST.
OTHERWISE...FAIRLY QUIET WEATHER PATTERN FOR MOST OF NORTHERN
ALASKA.

1929Z NPP/MODIS MICROPHYSICS RGB SATELLITE IMAGE SHOWS A BAND OF
STRATUS/FOG OVER THE ARCTIC COAST. THINKING THAT LOW STRATUS AND
AREAS OF FOG WILL PERSIST OVER THE NEXT FEW DAYS AS WINDS WILL BE LIGHT.

.ALOFT...

BROAD UPPER LEVEL TROUGH EXTENDS FROM CHUKOTSK PENINSULA SOUTHEAST
OVER THE WESTERN TWO-THIRDS OF AK WITH A RIDGE OVER THE EASTERN
THIRD OF AK AND WESTERN CANADA. THIS TROUGH IS EXPECTED TO WEAKEN
AND LIFTS NORTH THIS EVENING AS A 500 MB VORTEX MAX/TROUGH SWINGS
EAST FROM THE CHUKOTSK PENINSULA. ALL OPERATIONAL MODELS HAVE THIS
TROUGH DEEPENING AS IT PROGRESSES EAST OVER NORTHERN ALASKA.

COINCIDENT WITH THIS TROUGH...WEAK COLD AIR ADVECTION WILL ENSUE
OVER NORTHERN ALASKA. ORIGINATING OVER NORTHERN SIBERIA WITH
CHILLY H850 TEMPERATURES OF -30C...THIS AIRMASS WILL MODIFY AS IT
SPREADS SOUTHEAST AND OVER NORTHERN ALASKA. BY TUESDAY/WEDNESDAY H850
TEMPERATURES OF -15C TO -20C WILL RESIDE OVER THE BROOKS RANGE
NORTH AND -10C TO -15C NORTH OF THE ALASKA RANGE. THESE FORECAST
H850 TEMPERATURES ARE STILL SLIGHTLY ABOVE NORMAL FOR THIS TIME
OF YEAR. THERE ARE SLIGHT DIFFERENCES BETWEEN THE MODELS...ONLY 3C
TO 5C WARMER PER THE ECWMF. AT THE SURFACE...MAY SEE AROUND 10
DEGREES OF COOLING NORTH OF THE BROOKS RANGE BY MIDWEEK...BRINGING
TEMPERATURES BACK TO NEAR NORMAL.

A PROGRESSIVE AND HIGHLY AMPLIFIED RIDGE IS EXPECTED TO BEGIN
BUILDING OVER THE WESTERN BERING SEA MONDAY NIGHT...BY EARLY
WEDNESDAY AFTERNOON...THE RIDGE AXIS WILL EXTEND FROM THE CHUKOTSK
PENINSULA SOUTHEAST OVER SEWARD PENINSULA AND OVER KODIAK ISLAND.
THIS RIDGE WILL GRADUALLY SHIFT NORTHEAST THROUGH THE REMAINDER OF
THE WEEK.

WEAK SHORTWAVES WILL MOVE OVER THE NORTH SLOPE...WEST COAST...AND
WESTERN INTERIOR...BRINGING INCREASED CHANCES FOR SNOW SHOWERS
MONDAY. CHANCES FOR SNOW SHOWERS FOR THE REST OF THE INTERIOR WILL
INCREASE AS THE AFOREMENTIONED H500 TROUGH SWINGS EAST TUESDAY AND
WEDNESDAY.

.SURFACE...

A BROAD LOW PRESSURE/TROUGH EXISTS OVER THE NORTHERN GULF OF
ALASKA AND MAINLAND AK...WITH MULTIPLE LOW CENTERS BEING ANALYZED.
SURFACE HIGH PRESSURE RESIDES OVER SIBERIA AND ARCTIC OCEAN. THE
BROAD LOW PRESSURE/TROUGH WILL EXPAND NORTHWARD OVER THE BEAUFORT
SEA TONIGHT AND MONDAY...ALLOWING THE GRADIENT OVER THE WEST COAST TO
POINT HOPE AND ALONG THE ARCTIC COAST TO RELAX. THIS WILL ALLOW
WINDS TO GRADUALLY DIMINISH OVERNIGHT FOR THE EASTERN BEAUFORT
SEA...POINT HOPE AND THE YUKON DELTA COAST.

CURRENT GFS/NAM/ECWMF ARE DEVELOPING A STRONG LOW NEAR SHEMYA BY
12Z TUESDAY. AFTER 12Z TUESDAY...MODEL SOLUTIONS SIGNIFICANTLY
DIVERGE WITH THE DEVELOPMENT AND PROGRESSION OF THIS LOW AS IT
DEEPENS AND ROTATES AROUND OVER THE BERING SEA. WILL EVALUATE
FUTURE RUNS OF THE GFS/NAM/ECWMF AS DETAILS BECOME CLEARER TO SEE
IF THERE WILL BE IMPACTS FOR THE WEST COAST ASSOCIATED WITH THIS
LOW.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ220.

BRISK WIND ADVISORY FOR PKZ220-PKZ240-PKZ245.
&&

$$

LTH DEC 14




000
FXAK67 PAJK 211530
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
630 AM AKST SUN DEC 21 2014

.SHORT TERM...THE COMPLEXITY OF TODAY`S WEATHER IS EVIDENT BY
LOOKING AT SATELLITE IMAGERY. THERE`S NOT ONE FEATURE TO HANG YOUR
HAT ON...INSTEAD THERE ARE MULTIPLE BANDS OF PRECIP AND SMALL/WEAK
LOW CENTERS. HAVE ATTEMPTED TO ADD SOME TIMING TO THE SHOWERS
GOING ON BY THE MOVEMENT OF TWO LOWS/TROUGHS. A SMALL LOW OFF THE
COAST OF YAKUTAT HAS A TROUGH EXTENDING TO THE EAST OVER JUNEAU.
THERE IS A BAND OF LIGHT SHOWERS ALONG THIS TROUGH THAT WILL
SHIFT NORTH THROUGH THE DAY AS THE LOW WEAKENS AND MOVES TO THE
NW. A SECOND LOW IS DEVELOPING ALONG A TROUGH OVER THE FAR
SOUTHERN OUTSIDE WATERS AND WILL MOVE INLAND NEAR CAPE DECISION
THIS AFTERNOON THEN EAST THROUGH THE NIGHT. THERE HAVE BEEN SOME
MODERATE TO HEAVY SHOWERS ALONG THIS TROUGH AND WILL CONTINUE TO
BE THE CASE AS THE LOW MOVES INLAND. DIFFLUENT ONSHORE FLOW ALOFT
WILL ALSO HELP TO ENHANCE SOME OF THESE SHOWERS. BETWEEN THE TWO
FEATURES EXPECT SHOWERS TO BE MORE SCATTERED. YET ANOTHER TROUGH
WILL MOVE INTO THE NORTHERN COAST LATE TONIGHT AND INCREASE POPS
AGAIN.

THE TWO TROUGHS AT EITHER END OF THE PANHANDLE HAVE CAUSED A
SOMEWHAT WEAK PRESSURE PATTERN OVER THE AREA THIS MORNING. THE LOW CENTER
DEVELOPING TO THE SOUTH WILL CAUSE LIGHT NORTH WINDS DURING THE
DAY ON THE NORTH SIDE OF IT. ON THE SOUTH SIDE WINDS WILL BE
BREEZY AT TIMES...ESPECIALLY WITH SHOWERS...OUT OF THE S-SW. LATE
TONIGHT WHEN THE LOW WEAKENS BACK TO A TROUGH AND MOVES INTO
CANADA WINDS THROUGH ALL OF THE INSIDE WATERS WILL INCREASE OUT OF
THE SOUTH.

THE WIND SHIFT TO THE SOUTH WILL CAUSE OVERNIGHT TEMPERATURES TO
STAY FAIRLY STEADY AND MOSTLY ABOVE FREEZING. THE NORTHERN LYNN
CANAL REGION HOWEVER WILL SEE A JUMP UP WHEN THEY FLIP SOUTH SINCE
THEY`VE HAD A COLDER NORTH WIND FOR QUITE SOME TIME AND THIS WILL
BE A MORE NOTICEABLE CHANGE IN AIRMASS. A MAJOR FACTOR THAT WILL
COMPLICATE TIMING OF THE MIN TEMPERATURE WILL BE BREAKS BETWEEN
THE SHOWERS. THE CENTRAL PANHANDLE...INCLUDING JUNEAU...WILL SEE
THE MOST BREAKS THIS EVENING. EVAPORATIVE COOLING OF THE WET
SURFACE AND RADIATIONAL COOLING DUE TO THE BREAKS IN THE CLOUDS
WILL CAUSE TEMPERATURES TO DROP QUICKLY...THEN AS ANOTHER SHOWER
MOVES THROUGH OR A GUST OF WIND HAPPENS THE TEMPERATURE WILL SPIKE BACK
UP. FOR THIS REASON HAVE LIMITED MENTION OF SNOW DESPITE THE NEAR
FREEZING TEMPERATURES IN SOME PLACES...BUT WOULDN`T BE SURPRISED
IF SOME FLAKES MIX IN. THE BREAKS AND COOLING WILL ALSO CAUSE FOG
TO DEVELOP SO HAVE ADDED IN PATCHY FOG TO THE FORECAST FOR
TONIGHT OVER THE CENTRAL AREAS AND LATE TONIGHT AS SHOWERS MOVE
OUT OF THE SOUTHERN AREAS.

USED MAINLY THE NAM FOR UPDATES TO PRESSURE AND WIND FOR IT`S
HANDLING OF THE WEAK LOWS. FORECAST CONFIDENCE IS BELOW NORMAL
TIMING OF SHOWERS.

.LONG TERM...MODELS ARE SHIFTING THE TRACK OF A LOW FOR MON NIGHT-
TUE NIGHT SEWD...AND DECIDED TO FOLLOW SUIT IN THIS FORECAST. HAVE
USED A 00Z ECMWF AND NAM BLEND TO DO THIS FOR MON-TUE NIGHT.
THINGS COULD GET INTERESTING FOR WED-THU...BUT MODELS DIFFER
SOMEWHAT ON KEY FEATURES...SO DECIDED TO MAKE NO SIGNIFICANT
CHANGES TO THE LONG RANGE BEYOND WED.

WITH LOW TRACK FURTHER SE...POPS WERE LOWERED OVER THE NRN AREAS.
TUE-TUE NIGHT. THE FURTHER SE TRACK WILL ALSO ALLOW SOME COOLER
AIR TO MOVE INTO THE NRN AREA TUE NIGHT AND WED. HAVE LOWERED
TEMPS A BIT OVER THE N FOR THAT TIME FRAME. IF LOW TRACKS AS
CURRENTLY FORECASTED...MAY NEED WIND HEADLINES FOR THE SRN AREA
FOR AT LEAST THE TUE PERIOD. IF IT TRACKS MUCH FURTHER TO THE SE
THOUGH...THE STRONGEST WINDS WOULD STAY S OF THE AREA. LATER
SHIFTS WILL NEED TO WATCH THIS CLOSELY.

FOR WED-THU...WILL NEED TO WATCH FOR SHORTWAVES MOVING E ACROSS
THE GULF. WITH COOLER AIR MOVING IN FROM THE N...MAY END UP WITH
AN OVERRUNNING PRECIP EVENT AT SOME POINT WED-THU ESPECIALLY OVER
THE NRN AREAS. THIS IS ANOTHER TIME PERIOD LATER SHIFTS MAY NEED
TO ADJUST FROM CURRENT FORECAST.

FOR NEXT WEEKEND...MODELS SUGGEST LARGE SCALE RIDGE WILL TRY TO BUILD
OVER THE AREA BUT SIGNIFICANT RUN TO RUN CHANGES ON THIS FEATURE
MAKE THIS TIME FRAME A DIFFICULT FORECAST AT THIS POINT. IT DOES
SEEM THE THREAT FOR A SIGNIFICANT COLD OUTBREAK IS REDUCED THOUGH
AS NONE OF THE MODELS SHOW A STRONG RIDGE BUILDING FAR ENOUGH TO
THE W TO DRIVE IN THE DEEP COLD AIR FROM THE N. ALSO...CURRENT
MODELS SUGGEST LESS OF A THREAT FOR A BLOCKING HIGH TO FORM.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 211530
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
630 AM AKST SUN DEC 21 2014

.SHORT TERM...THE COMPLEXITY OF TODAY`S WEATHER IS EVIDENT BY
LOOKING AT SATELLITE IMAGERY. THERE`S NOT ONE FEATURE TO HANG YOUR
HAT ON...INSTEAD THERE ARE MULTIPLE BANDS OF PRECIP AND SMALL/WEAK
LOW CENTERS. HAVE ATTEMPTED TO ADD SOME TIMING TO THE SHOWERS
GOING ON BY THE MOVEMENT OF TWO LOWS/TROUGHS. A SMALL LOW OFF THE
COAST OF YAKUTAT HAS A TROUGH EXTENDING TO THE EAST OVER JUNEAU.
THERE IS A BAND OF LIGHT SHOWERS ALONG THIS TROUGH THAT WILL
SHIFT NORTH THROUGH THE DAY AS THE LOW WEAKENS AND MOVES TO THE
NW. A SECOND LOW IS DEVELOPING ALONG A TROUGH OVER THE FAR
SOUTHERN OUTSIDE WATERS AND WILL MOVE INLAND NEAR CAPE DECISION
THIS AFTERNOON THEN EAST THROUGH THE NIGHT. THERE HAVE BEEN SOME
MODERATE TO HEAVY SHOWERS ALONG THIS TROUGH AND WILL CONTINUE TO
BE THE CASE AS THE LOW MOVES INLAND. DIFFLUENT ONSHORE FLOW ALOFT
WILL ALSO HELP TO ENHANCE SOME OF THESE SHOWERS. BETWEEN THE TWO
FEATURES EXPECT SHOWERS TO BE MORE SCATTERED. YET ANOTHER TROUGH
WILL MOVE INTO THE NORTHERN COAST LATE TONIGHT AND INCREASE POPS
AGAIN.

THE TWO TROUGHS AT EITHER END OF THE PANHANDLE HAVE CAUSED A
SOMEWHAT WEAK PRESSURE PATTERN OVER THE AREA THIS MORNING. THE LOW CENTER
DEVELOPING TO THE SOUTH WILL CAUSE LIGHT NORTH WINDS DURING THE
DAY ON THE NORTH SIDE OF IT. ON THE SOUTH SIDE WINDS WILL BE
BREEZY AT TIMES...ESPECIALLY WITH SHOWERS...OUT OF THE S-SW. LATE
TONIGHT WHEN THE LOW WEAKENS BACK TO A TROUGH AND MOVES INTO
CANADA WINDS THROUGH ALL OF THE INSIDE WATERS WILL INCREASE OUT OF
THE SOUTH.

THE WIND SHIFT TO THE SOUTH WILL CAUSE OVERNIGHT TEMPERATURES TO
STAY FAIRLY STEADY AND MOSTLY ABOVE FREEZING. THE NORTHERN LYNN
CANAL REGION HOWEVER WILL SEE A JUMP UP WHEN THEY FLIP SOUTH SINCE
THEY`VE HAD A COLDER NORTH WIND FOR QUITE SOME TIME AND THIS WILL
BE A MORE NOTICEABLE CHANGE IN AIRMASS. A MAJOR FACTOR THAT WILL
COMPLICATE TIMING OF THE MIN TEMPERATURE WILL BE BREAKS BETWEEN
THE SHOWERS. THE CENTRAL PANHANDLE...INCLUDING JUNEAU...WILL SEE
THE MOST BREAKS THIS EVENING. EVAPORATIVE COOLING OF THE WET
SURFACE AND RADIATIONAL COOLING DUE TO THE BREAKS IN THE CLOUDS
WILL CAUSE TEMPERATURES TO DROP QUICKLY...THEN AS ANOTHER SHOWER
MOVES THROUGH OR A GUST OF WIND HAPPENS THE TEMPERATURE WILL SPIKE BACK
UP. FOR THIS REASON HAVE LIMITED MENTION OF SNOW DESPITE THE NEAR
FREEZING TEMPERATURES IN SOME PLACES...BUT WOULDN`T BE SURPRISED
IF SOME FLAKES MIX IN. THE BREAKS AND COOLING WILL ALSO CAUSE FOG
TO DEVELOP SO HAVE ADDED IN PATCHY FOG TO THE FORECAST FOR
TONIGHT OVER THE CENTRAL AREAS AND LATE TONIGHT AS SHOWERS MOVE
OUT OF THE SOUTHERN AREAS.

USED MAINLY THE NAM FOR UPDATES TO PRESSURE AND WIND FOR IT`S
HANDLING OF THE WEAK LOWS. FORECAST CONFIDENCE IS BELOW NORMAL
TIMING OF SHOWERS.

.LONG TERM...MODELS ARE SHIFTING THE TRACK OF A LOW FOR MON NIGHT-
TUE NIGHT SEWD...AND DECIDED TO FOLLOW SUIT IN THIS FORECAST. HAVE
USED A 00Z ECMWF AND NAM BLEND TO DO THIS FOR MON-TUE NIGHT.
THINGS COULD GET INTERESTING FOR WED-THU...BUT MODELS DIFFER
SOMEWHAT ON KEY FEATURES...SO DECIDED TO MAKE NO SIGNIFICANT
CHANGES TO THE LONG RANGE BEYOND WED.

WITH LOW TRACK FURTHER SE...POPS WERE LOWERED OVER THE NRN AREAS.
TUE-TUE NIGHT. THE FURTHER SE TRACK WILL ALSO ALLOW SOME COOLER
AIR TO MOVE INTO THE NRN AREA TUE NIGHT AND WED. HAVE LOWERED
TEMPS A BIT OVER THE N FOR THAT TIME FRAME. IF LOW TRACKS AS
CURRENTLY FORECASTED...MAY NEED WIND HEADLINES FOR THE SRN AREA
FOR AT LEAST THE TUE PERIOD. IF IT TRACKS MUCH FURTHER TO THE SE
THOUGH...THE STRONGEST WINDS WOULD STAY S OF THE AREA. LATER
SHIFTS WILL NEED TO WATCH THIS CLOSELY.

FOR WED-THU...WILL NEED TO WATCH FOR SHORTWAVES MOVING E ACROSS
THE GULF. WITH COOLER AIR MOVING IN FROM THE N...MAY END UP WITH
AN OVERRUNNING PRECIP EVENT AT SOME POINT WED-THU ESPECIALLY OVER
THE NRN AREAS. THIS IS ANOTHER TIME PERIOD LATER SHIFTS MAY NEED
TO ADJUST FROM CURRENT FORECAST.

FOR NEXT WEEKEND...MODELS SUGGEST LARGE SCALE RIDGE WILL TRY TO BUILD
OVER THE AREA BUT SIGNIFICANT RUN TO RUN CHANGES ON THIS FEATURE
MAKE THIS TIME FRAME A DIFFICULT FORECAST AT THIS POINT. IT DOES
SEEM THE THREAT FOR A SIGNIFICANT COLD OUTBREAK IS REDUCED THOUGH
AS NONE OF THE MODELS SHOW A STRONG RIDGE BUILDING FAR ENOUGH TO
THE W TO DRIVE IN THE DEEP COLD AIR FROM THE N. ALSO...CURRENT
MODELS SUGGEST LESS OF A THREAT FOR A BLOCKING HIGH TO FORM.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 211530
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
630 AM AKST SUN DEC 21 2014

.SHORT TERM...THE COMPLEXITY OF TODAY`S WEATHER IS EVIDENT BY
LOOKING AT SATELLITE IMAGERY. THERE`S NOT ONE FEATURE TO HANG YOUR
HAT ON...INSTEAD THERE ARE MULTIPLE BANDS OF PRECIP AND SMALL/WEAK
LOW CENTERS. HAVE ATTEMPTED TO ADD SOME TIMING TO THE SHOWERS
GOING ON BY THE MOVEMENT OF TWO LOWS/TROUGHS. A SMALL LOW OFF THE
COAST OF YAKUTAT HAS A TROUGH EXTENDING TO THE EAST OVER JUNEAU.
THERE IS A BAND OF LIGHT SHOWERS ALONG THIS TROUGH THAT WILL
SHIFT NORTH THROUGH THE DAY AS THE LOW WEAKENS AND MOVES TO THE
NW. A SECOND LOW IS DEVELOPING ALONG A TROUGH OVER THE FAR
SOUTHERN OUTSIDE WATERS AND WILL MOVE INLAND NEAR CAPE DECISION
THIS AFTERNOON THEN EAST THROUGH THE NIGHT. THERE HAVE BEEN SOME
MODERATE TO HEAVY SHOWERS ALONG THIS TROUGH AND WILL CONTINUE TO
BE THE CASE AS THE LOW MOVES INLAND. DIFFLUENT ONSHORE FLOW ALOFT
WILL ALSO HELP TO ENHANCE SOME OF THESE SHOWERS. BETWEEN THE TWO
FEATURES EXPECT SHOWERS TO BE MORE SCATTERED. YET ANOTHER TROUGH
WILL MOVE INTO THE NORTHERN COAST LATE TONIGHT AND INCREASE POPS
AGAIN.

THE TWO TROUGHS AT EITHER END OF THE PANHANDLE HAVE CAUSED A
SOMEWHAT WEAK PRESSURE PATTERN OVER THE AREA THIS MORNING. THE LOW CENTER
DEVELOPING TO THE SOUTH WILL CAUSE LIGHT NORTH WINDS DURING THE
DAY ON THE NORTH SIDE OF IT. ON THE SOUTH SIDE WINDS WILL BE
BREEZY AT TIMES...ESPECIALLY WITH SHOWERS...OUT OF THE S-SW. LATE
TONIGHT WHEN THE LOW WEAKENS BACK TO A TROUGH AND MOVES INTO
CANADA WINDS THROUGH ALL OF THE INSIDE WATERS WILL INCREASE OUT OF
THE SOUTH.

THE WIND SHIFT TO THE SOUTH WILL CAUSE OVERNIGHT TEMPERATURES TO
STAY FAIRLY STEADY AND MOSTLY ABOVE FREEZING. THE NORTHERN LYNN
CANAL REGION HOWEVER WILL SEE A JUMP UP WHEN THEY FLIP SOUTH SINCE
THEY`VE HAD A COLDER NORTH WIND FOR QUITE SOME TIME AND THIS WILL
BE A MORE NOTICEABLE CHANGE IN AIRMASS. A MAJOR FACTOR THAT WILL
COMPLICATE TIMING OF THE MIN TEMPERATURE WILL BE BREAKS BETWEEN
THE SHOWERS. THE CENTRAL PANHANDLE...INCLUDING JUNEAU...WILL SEE
THE MOST BREAKS THIS EVENING. EVAPORATIVE COOLING OF THE WET
SURFACE AND RADIATIONAL COOLING DUE TO THE BREAKS IN THE CLOUDS
WILL CAUSE TEMPERATURES TO DROP QUICKLY...THEN AS ANOTHER SHOWER
MOVES THROUGH OR A GUST OF WIND HAPPENS THE TEMPERATURE WILL SPIKE BACK
UP. FOR THIS REASON HAVE LIMITED MENTION OF SNOW DESPITE THE NEAR
FREEZING TEMPERATURES IN SOME PLACES...BUT WOULDN`T BE SURPRISED
IF SOME FLAKES MIX IN. THE BREAKS AND COOLING WILL ALSO CAUSE FOG
TO DEVELOP SO HAVE ADDED IN PATCHY FOG TO THE FORECAST FOR
TONIGHT OVER THE CENTRAL AREAS AND LATE TONIGHT AS SHOWERS MOVE
OUT OF THE SOUTHERN AREAS.

USED MAINLY THE NAM FOR UPDATES TO PRESSURE AND WIND FOR IT`S
HANDLING OF THE WEAK LOWS. FORECAST CONFIDENCE IS BELOW NORMAL
TIMING OF SHOWERS.

.LONG TERM...MODELS ARE SHIFTING THE TRACK OF A LOW FOR MON NIGHT-
TUE NIGHT SEWD...AND DECIDED TO FOLLOW SUIT IN THIS FORECAST. HAVE
USED A 00Z ECMWF AND NAM BLEND TO DO THIS FOR MON-TUE NIGHT.
THINGS COULD GET INTERESTING FOR WED-THU...BUT MODELS DIFFER
SOMEWHAT ON KEY FEATURES...SO DECIDED TO MAKE NO SIGNIFICANT
CHANGES TO THE LONG RANGE BEYOND WED.

WITH LOW TRACK FURTHER SE...POPS WERE LOWERED OVER THE NRN AREAS.
TUE-TUE NIGHT. THE FURTHER SE TRACK WILL ALSO ALLOW SOME COOLER
AIR TO MOVE INTO THE NRN AREA TUE NIGHT AND WED. HAVE LOWERED
TEMPS A BIT OVER THE N FOR THAT TIME FRAME. IF LOW TRACKS AS
CURRENTLY FORECASTED...MAY NEED WIND HEADLINES FOR THE SRN AREA
FOR AT LEAST THE TUE PERIOD. IF IT TRACKS MUCH FURTHER TO THE SE
THOUGH...THE STRONGEST WINDS WOULD STAY S OF THE AREA. LATER
SHIFTS WILL NEED TO WATCH THIS CLOSELY.

FOR WED-THU...WILL NEED TO WATCH FOR SHORTWAVES MOVING E ACROSS
THE GULF. WITH COOLER AIR MOVING IN FROM THE N...MAY END UP WITH
AN OVERRUNNING PRECIP EVENT AT SOME POINT WED-THU ESPECIALLY OVER
THE NRN AREAS. THIS IS ANOTHER TIME PERIOD LATER SHIFTS MAY NEED
TO ADJUST FROM CURRENT FORECAST.

FOR NEXT WEEKEND...MODELS SUGGEST LARGE SCALE RIDGE WILL TRY TO BUILD
OVER THE AREA BUT SIGNIFICANT RUN TO RUN CHANGES ON THIS FEATURE
MAKE THIS TIME FRAME A DIFFICULT FORECAST AT THIS POINT. IT DOES
SEEM THE THREAT FOR A SIGNIFICANT COLD OUTBREAK IS REDUCED THOUGH
AS NONE OF THE MODELS SHOW A STRONG RIDGE BUILDING FAR ENOUGH TO
THE W TO DRIVE IN THE DEEP COLD AIR FROM THE N. ALSO...CURRENT
MODELS SUGGEST LESS OF A THREAT FOR A BLOCKING HIGH TO FORM.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK67 PAJK 211530
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
630 AM AKST SUN DEC 21 2014

.SHORT TERM...THE COMPLEXITY OF TODAY`S WEATHER IS EVIDENT BY
LOOKING AT SATELLITE IMAGERY. THERE`S NOT ONE FEATURE TO HANG YOUR
HAT ON...INSTEAD THERE ARE MULTIPLE BANDS OF PRECIP AND SMALL/WEAK
LOW CENTERS. HAVE ATTEMPTED TO ADD SOME TIMING TO THE SHOWERS
GOING ON BY THE MOVEMENT OF TWO LOWS/TROUGHS. A SMALL LOW OFF THE
COAST OF YAKUTAT HAS A TROUGH EXTENDING TO THE EAST OVER JUNEAU.
THERE IS A BAND OF LIGHT SHOWERS ALONG THIS TROUGH THAT WILL
SHIFT NORTH THROUGH THE DAY AS THE LOW WEAKENS AND MOVES TO THE
NW. A SECOND LOW IS DEVELOPING ALONG A TROUGH OVER THE FAR
SOUTHERN OUTSIDE WATERS AND WILL MOVE INLAND NEAR CAPE DECISION
THIS AFTERNOON THEN EAST THROUGH THE NIGHT. THERE HAVE BEEN SOME
MODERATE TO HEAVY SHOWERS ALONG THIS TROUGH AND WILL CONTINUE TO
BE THE CASE AS THE LOW MOVES INLAND. DIFFLUENT ONSHORE FLOW ALOFT
WILL ALSO HELP TO ENHANCE SOME OF THESE SHOWERS. BETWEEN THE TWO
FEATURES EXPECT SHOWERS TO BE MORE SCATTERED. YET ANOTHER TROUGH
WILL MOVE INTO THE NORTHERN COAST LATE TONIGHT AND INCREASE POPS
AGAIN.

THE TWO TROUGHS AT EITHER END OF THE PANHANDLE HAVE CAUSED A
SOMEWHAT WEAK PRESSURE PATTERN OVER THE AREA THIS MORNING. THE LOW CENTER
DEVELOPING TO THE SOUTH WILL CAUSE LIGHT NORTH WINDS DURING THE
DAY ON THE NORTH SIDE OF IT. ON THE SOUTH SIDE WINDS WILL BE
BREEZY AT TIMES...ESPECIALLY WITH SHOWERS...OUT OF THE S-SW. LATE
TONIGHT WHEN THE LOW WEAKENS BACK TO A TROUGH AND MOVES INTO
CANADA WINDS THROUGH ALL OF THE INSIDE WATERS WILL INCREASE OUT OF
THE SOUTH.

THE WIND SHIFT TO THE SOUTH WILL CAUSE OVERNIGHT TEMPERATURES TO
STAY FAIRLY STEADY AND MOSTLY ABOVE FREEZING. THE NORTHERN LYNN
CANAL REGION HOWEVER WILL SEE A JUMP UP WHEN THEY FLIP SOUTH SINCE
THEY`VE HAD A COLDER NORTH WIND FOR QUITE SOME TIME AND THIS WILL
BE A MORE NOTICEABLE CHANGE IN AIRMASS. A MAJOR FACTOR THAT WILL
COMPLICATE TIMING OF THE MIN TEMPERATURE WILL BE BREAKS BETWEEN
THE SHOWERS. THE CENTRAL PANHANDLE...INCLUDING JUNEAU...WILL SEE
THE MOST BREAKS THIS EVENING. EVAPORATIVE COOLING OF THE WET
SURFACE AND RADIATIONAL COOLING DUE TO THE BREAKS IN THE CLOUDS
WILL CAUSE TEMPERATURES TO DROP QUICKLY...THEN AS ANOTHER SHOWER
MOVES THROUGH OR A GUST OF WIND HAPPENS THE TEMPERATURE WILL SPIKE BACK
UP. FOR THIS REASON HAVE LIMITED MENTION OF SNOW DESPITE THE NEAR
FREEZING TEMPERATURES IN SOME PLACES...BUT WOULDN`T BE SURPRISED
IF SOME FLAKES MIX IN. THE BREAKS AND COOLING WILL ALSO CAUSE FOG
TO DEVELOP SO HAVE ADDED IN PATCHY FOG TO THE FORECAST FOR
TONIGHT OVER THE CENTRAL AREAS AND LATE TONIGHT AS SHOWERS MOVE
OUT OF THE SOUTHERN AREAS.

USED MAINLY THE NAM FOR UPDATES TO PRESSURE AND WIND FOR IT`S
HANDLING OF THE WEAK LOWS. FORECAST CONFIDENCE IS BELOW NORMAL
TIMING OF SHOWERS.

.LONG TERM...MODELS ARE SHIFTING THE TRACK OF A LOW FOR MON NIGHT-
TUE NIGHT SEWD...AND DECIDED TO FOLLOW SUIT IN THIS FORECAST. HAVE
USED A 00Z ECMWF AND NAM BLEND TO DO THIS FOR MON-TUE NIGHT.
THINGS COULD GET INTERESTING FOR WED-THU...BUT MODELS DIFFER
SOMEWHAT ON KEY FEATURES...SO DECIDED TO MAKE NO SIGNIFICANT
CHANGES TO THE LONG RANGE BEYOND WED.

WITH LOW TRACK FURTHER SE...POPS WERE LOWERED OVER THE NRN AREAS.
TUE-TUE NIGHT. THE FURTHER SE TRACK WILL ALSO ALLOW SOME COOLER
AIR TO MOVE INTO THE NRN AREA TUE NIGHT AND WED. HAVE LOWERED
TEMPS A BIT OVER THE N FOR THAT TIME FRAME. IF LOW TRACKS AS
CURRENTLY FORECASTED...MAY NEED WIND HEADLINES FOR THE SRN AREA
FOR AT LEAST THE TUE PERIOD. IF IT TRACKS MUCH FURTHER TO THE SE
THOUGH...THE STRONGEST WINDS WOULD STAY S OF THE AREA. LATER
SHIFTS WILL NEED TO WATCH THIS CLOSELY.

FOR WED-THU...WILL NEED TO WATCH FOR SHORTWAVES MOVING E ACROSS
THE GULF. WITH COOLER AIR MOVING IN FROM THE N...MAY END UP WITH
AN OVERRUNNING PRECIP EVENT AT SOME POINT WED-THU ESPECIALLY OVER
THE NRN AREAS. THIS IS ANOTHER TIME PERIOD LATER SHIFTS MAY NEED
TO ADJUST FROM CURRENT FORECAST.

FOR NEXT WEEKEND...MODELS SUGGEST LARGE SCALE RIDGE WILL TRY TO BUILD
OVER THE AREA BUT SIGNIFICANT RUN TO RUN CHANGES ON THIS FEATURE
MAKE THIS TIME FRAME A DIFFICULT FORECAST AT THIS POINT. IT DOES
SEEM THE THREAT FOR A SIGNIFICANT COLD OUTBREAK IS REDUCED THOUGH
AS NONE OF THE MODELS SHOW A STRONG RIDGE BUILDING FAR ENOUGH TO
THE W TO DRIVE IN THE DEEP COLD AIR FROM THE N. ALSO...CURRENT
MODELS SUGGEST LESS OF A THREAT FOR A BLOCKING HIGH TO FORM.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY FOR PKZ036-041.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ022-042-043-051-052.

&&

$$

FERRIN/RWT

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU








000
FXAK69 PAFG 211528 AAA
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FAIRBANKS AK
628 AM AKST SUN DEC 21 2014

UPDATE ADDS PARAGRAPH TO SURFACE SECTION

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.

CURRENT GFS/ECMWF AND ENSEMBLE MEANS INDICATE THE POSSIBILITY
OF A MODERATELY STRONG LOW MOVING INTO THE SOUTHERN BERING SEA
FRIDAY AFTERNOON OR FRIDAY NIGHT...WITH POTENTIAL FOR GALES OVER
THE NORTHERN BERING SEA.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ220.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240-PKZ245.
&&

$$

DEC 14




000
FXAK69 PAFG 211528 AAA
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FAIRBANKS AK
628 AM AKST SUN DEC 21 2014

UPDATE ADDS PARAGRAPH TO SURFACE SECTION

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.

CURRENT GFS/ECMWF AND ENSEMBLE MEANS INDICATE THE POSSIBILITY
OF A MODERATELY STRONG LOW MOVING INTO THE SOUTHERN BERING SEA
FRIDAY AFTERNOON OR FRIDAY NIGHT...WITH POTENTIAL FOR GALES OVER
THE NORTHERN BERING SEA.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

SMALL CRAFT ADVISORY FOR PKZ210.

GALE WARNING FOR PKZ220.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240-PKZ245.
&&

$$

DEC 14



000
FXAK68 PAFC 211329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
429 AM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...

AN AREA OF LOW PRESSURE OVER THE NORTHERN GULF CONTINUES TO PUSH
TO THE WEST/NORTHWEST OF MIDDLETON ISLAND EARLY THIS MORNING.
THIS LOW PRESSURE SYSTEM HELD TOGETHER A BIT LONGER THAN EXPECTED
OVER THE PAST SEVERAL FORECAST RUNS...ALLOWING FOR A STRONGER
BARRIER JET OVER THE NORTHERN GULF AND A SLIGHTLY SLOWER WESTWARD
TRACK. WARM AIR ADVECTION ON THE BACKSIDE OF THE LOW RAPIDLY
WARMED THE NORTHERN GULF COAST (CORDOVA AREA) FROM THE MID 30S TO
THE MID 40S AND TRANSITIONED PRECIPITATION FROM SNOW TO RAIN.
SNOWFALL CONTINUES TO OVERSPREAD MUCH OF THE GULF COAST AND IS
PUSHING FURTHER INLAND OVER THE COPPER RIVER BASIN...ANCHORAGE AND
PARTS OF THE MAT-SU VALLEY. THE LONGWAVE TROUGH EXTENDING FROM THE
KAMCHATKA PENINSULA TO THE PACIFIC NORTHWEST COAST OF THE UNITED
STATES CONTINUES TO AMPLIFY AS A POTENT SHORTWAVE AND AN UPPER
LEVEL JET RANGING FROM 150 TO 160 KT HELPS DIG THE TROUGH FURTHER
SOUTH IN THE NORTH PACIFIC. WEAK SURFACE AND UPPER LEVEL BASED
RIDGING IS DEVELOPING OVER THE WESTERN BERING SEA EARLY THIS
MORNING WHICH HAS HELPED TO SHIFT THE REMNANTS OF A WEAK LOW JUST
SOUTH OF THE ALEUTIAN CHAIN INTO THE WESTERN GULF OF ALASKA. AN
EVEN MORE POTENT JET (POSSIBLY APPROACHING 200 KT) HAS BEGUN TO
SET UP OVER EAST ASIA AND HAS HELPED TO INTENSIFY A LOW OVER THE
KAMCHATKA PENINSULA THAT HAS BEGUN TO PUSH A FRONT TOWARD THE
WESTERN BERING SEA.

&&

.MODEL DISCUSSION...

THE 00Z AND 06Z NUMERICAL GUIDANCE WAS STRUGGLING TO INITIALIZE
THE LOW IN THE NORTHERN GULF PRESENTLY LOCATED NORTHWEST OF
MIDDLETON ISLAND. BASED ON SURFACE OBSERVATIONS AND A SCATTEROMETER
PASS AT 0510Z...IT APPEARS THE 00Z/06Z NAM HAS INITIALIZED THE
BEST...WITH THE ECMWF BEING TOO FAST AND THE GEM BEING WAY TOO
SLOW. THE GFS IS A HUGE OUTLIER WITH THE INITIALIZATION AS IT HAD
MORE OF A COMPLEX LOW FEATURE THAN AN ACTUAL CLOSED LOW.
HOWEVER...MODELS ARE IN GOOD AGREEMENT WITH SNOW CONTINUING ACROSS
MUCH OF SOUTHCENTRAL ALASKA THROUGH THE BEGINNING OF THE UPCOMING
WEEK...WITH SNOWFALL BECOMING MORE SHOWERY IN NATURE WITH SOME
ELEVATED INSTABILITY AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
PUSHING ACROSS THE AREA. THE NAM WAS UTILIZED FOR THE MOST PART
OVER THE EAST DOMAIN DUE TO BETTER INITIALIZATION.

OUT WEST...MODELS REMAIN IN VERY GOOD AGREEMENT WITH A WEAK
SURFACE AND UPPER LEVEL RIDGE MOVING FROM THE WESTERN BERING SEA
TO EASTERN BERING SEA DURING THE COURSE OF THE WEEK. MODEL
AGREEMENT BEGINS TO FALTER LATE MONDAY INTO TUESDAY AS A LOW
DEVELOPS TO THE WEST OF SHEMYA AND PUSHES INTO THE BERING SEA.
WHILE THE MODELS ARE IN SOMEWHAT AGREEMENT WITH STRENGTH AND
POSITION...THE STANDARD DEVIATION OF OVER 5 MB IS A BIT DISCONCERTING.
NEVERTHELESS...IT APPEARS STORM FORCE WINDS WILL BE LIKELY WITH A
RAPIDLY DEVELOPING LOW INTERACTING WITH A POTENT (180 KT TO 200
KT) JET STREAK. A MIX OF THE ECMWF AND NAM WAS UTILIZED OVER THE
WESTERN DOMAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE LOW IN THE NORTHERN GULF IS BRINGING IN ENOUGH MOISTURE FROM
THE SOUTH TO BRING LIGHT SNOW TO MANY LOCATIONS AROUND SOUTHCENTRAL.
HOWEVER...IN SOME PLACES ALONG THE NORTH GULF COAST IT REMAINS
WARM ENOUGH FOR RAIN. AS THE LOW TRACKS WEST INTO THE COOK INLET
AREA TODAY FLOW WILL BECOME MORE SOUTHERLY RESULTING IN A BETTER
CHANCE FOR SNOW SHOWERS FROM THE ANCHORAGE BOWL AREA INTO THE MAT-
SU VALLEY. THIS HIGHER CHANCE OF LIGHT SNOW WILL LAST THROUGH
TONIGHT BEFORE THE LOW WEAKENS AND MOVES SOUTH.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE REMNANTS OF A DISSIPATING LOW LOCATED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
THE ALASKA RANGE THROUGH MONDAY. THE WINDS WILL REMAIN NORTHERLY
RESULTING IN OFFSHORE FLOW RESULTING IN DRIER CONDITIONS FOR THE
REST OF SOUTHWEST ALASKA THROUGH TUESDAY. THE NORTHERLY WINDS
WILL BRING IN COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES FOR THE EARLY PART OF THIS UPCOMING WEEK.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE EAST SIBERIAN HIGH WILL REMAIN IN PLACE RESULTING IN
NORTHERLY WINDS THROUGH THE BERING STRAIT SOUTHWARD INTO THE
NORTHERN BERING SEA THROUGH SUNDAY BEFORE SHIFTING TO THE
SOUTHEAST BY MONDAY. THIS WILL CONTINUE TO BRING SHOWERY
PRECIPITATION TO THE NORTHERN BERING SEA WITH COOLER TEMPERATURES
THROUGH SUNDAY. BY SUNDAY NIGHT A WEATHER FRONT WILL PUSH THROUGH
THE WESTERN ALEUTIANS INTO THE WESTERN TO CENTRAL BERING SEA BY
MONDAY...FOLLOWED BY A NORTH PACIFIC STORM FORCE LOW TRACKING
THROUGH SHEMYA BY MONDAY NIGHT BEFORE MOVING INTO THE WESTERN
BERING SEA BY TUESDAY. A SECONDARY WEATHER FRONT FROM THE
AFOREMENTIONED LOW WILL BE POSITIONED JUST WEST OF UNALASKA BY
TUESDAY MORNING. THIS WILL BRING WARMER TEMPERATURES WITH STORM
FORCE WINDS THROUGH THE WESTERN ALEUTIANS INTO THE SOUTHERN BERING
SEA. THE CENTRAL TO EASTERN ALEUTIANS WILL RECEIVE GALE FORCE
WINDS SPILLING OVER INTO THE CENTRAL BERING SEA BY TUESDAY. AS THE
NORTH PACIFIC LOW MOVES INTO THE BERING SEA BY TUESDAY...THIS WILL
PRODUCE A LARGE SWATH OF MOISTURE AND PRECIPITATION THROUGH THE
ALEUTIANS AND THE BERING SEA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 177 178
 HEAVY FREEZING SPRAY 180 181 185
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MMC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...KH



000
FXAK68 PAFC 211329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
429 AM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...

AN AREA OF LOW PRESSURE OVER THE NORTHERN GULF CONTINUES TO PUSH
TO THE WEST/NORTHWEST OF MIDDLETON ISLAND EARLY THIS MORNING.
THIS LOW PRESSURE SYSTEM HELD TOGETHER A BIT LONGER THAN EXPECTED
OVER THE PAST SEVERAL FORECAST RUNS...ALLOWING FOR A STRONGER
BARRIER JET OVER THE NORTHERN GULF AND A SLIGHTLY SLOWER WESTWARD
TRACK. WARM AIR ADVECTION ON THE BACKSIDE OF THE LOW RAPIDLY
WARMED THE NORTHERN GULF COAST (CORDOVA AREA) FROM THE MID 30S TO
THE MID 40S AND TRANSITIONED PRECIPITATION FROM SNOW TO RAIN.
SNOWFALL CONTINUES TO OVERSPREAD MUCH OF THE GULF COAST AND IS
PUSHING FURTHER INLAND OVER THE COPPER RIVER BASIN...ANCHORAGE AND
PARTS OF THE MAT-SU VALLEY. THE LONGWAVE TROUGH EXTENDING FROM THE
KAMCHATKA PENINSULA TO THE PACIFIC NORTHWEST COAST OF THE UNITED
STATES CONTINUES TO AMPLIFY AS A POTENT SHORTWAVE AND AN UPPER
LEVEL JET RANGING FROM 150 TO 160 KT HELPS DIG THE TROUGH FURTHER
SOUTH IN THE NORTH PACIFIC. WEAK SURFACE AND UPPER LEVEL BASED
RIDGING IS DEVELOPING OVER THE WESTERN BERING SEA EARLY THIS
MORNING WHICH HAS HELPED TO SHIFT THE REMNANTS OF A WEAK LOW JUST
SOUTH OF THE ALEUTIAN CHAIN INTO THE WESTERN GULF OF ALASKA. AN
EVEN MORE POTENT JET (POSSIBLY APPROACHING 200 KT) HAS BEGUN TO
SET UP OVER EAST ASIA AND HAS HELPED TO INTENSIFY A LOW OVER THE
KAMCHATKA PENINSULA THAT HAS BEGUN TO PUSH A FRONT TOWARD THE
WESTERN BERING SEA.

&&

.MODEL DISCUSSION...

THE 00Z AND 06Z NUMERICAL GUIDANCE WAS STRUGGLING TO INITIALIZE
THE LOW IN THE NORTHERN GULF PRESENTLY LOCATED NORTHWEST OF
MIDDLETON ISLAND. BASED ON SURFACE OBSERVATIONS AND A SCATTEROMETER
PASS AT 0510Z...IT APPEARS THE 00Z/06Z NAM HAS INITIALIZED THE
BEST...WITH THE ECMWF BEING TOO FAST AND THE GEM BEING WAY TOO
SLOW. THE GFS IS A HUGE OUTLIER WITH THE INITIALIZATION AS IT HAD
MORE OF A COMPLEX LOW FEATURE THAN AN ACTUAL CLOSED LOW.
HOWEVER...MODELS ARE IN GOOD AGREEMENT WITH SNOW CONTINUING ACROSS
MUCH OF SOUTHCENTRAL ALASKA THROUGH THE BEGINNING OF THE UPCOMING
WEEK...WITH SNOWFALL BECOMING MORE SHOWERY IN NATURE WITH SOME
ELEVATED INSTABILITY AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
PUSHING ACROSS THE AREA. THE NAM WAS UTILIZED FOR THE MOST PART
OVER THE EAST DOMAIN DUE TO BETTER INITIALIZATION.

OUT WEST...MODELS REMAIN IN VERY GOOD AGREEMENT WITH A WEAK
SURFACE AND UPPER LEVEL RIDGE MOVING FROM THE WESTERN BERING SEA
TO EASTERN BERING SEA DURING THE COURSE OF THE WEEK. MODEL
AGREEMENT BEGINS TO FALTER LATE MONDAY INTO TUESDAY AS A LOW
DEVELOPS TO THE WEST OF SHEMYA AND PUSHES INTO THE BERING SEA.
WHILE THE MODELS ARE IN SOMEWHAT AGREEMENT WITH STRENGTH AND
POSITION...THE STANDARD DEVIATION OF OVER 5 MB IS A BIT DISCONCERTING.
NEVERTHELESS...IT APPEARS STORM FORCE WINDS WILL BE LIKELY WITH A
RAPIDLY DEVELOPING LOW INTERACTING WITH A POTENT (180 KT TO 200
KT) JET STREAK. A MIX OF THE ECMWF AND NAM WAS UTILIZED OVER THE
WESTERN DOMAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE LOW IN THE NORTHERN GULF IS BRINGING IN ENOUGH MOISTURE FROM
THE SOUTH TO BRING LIGHT SNOW TO MANY LOCATIONS AROUND SOUTHCENTRAL.
HOWEVER...IN SOME PLACES ALONG THE NORTH GULF COAST IT REMAINS
WARM ENOUGH FOR RAIN. AS THE LOW TRACKS WEST INTO THE COOK INLET
AREA TODAY FLOW WILL BECOME MORE SOUTHERLY RESULTING IN A BETTER
CHANCE FOR SNOW SHOWERS FROM THE ANCHORAGE BOWL AREA INTO THE MAT-
SU VALLEY. THIS HIGHER CHANCE OF LIGHT SNOW WILL LAST THROUGH
TONIGHT BEFORE THE LOW WEAKENS AND MOVES SOUTH.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE REMNANTS OF A DISSIPATING LOW LOCATED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
THE ALASKA RANGE THROUGH MONDAY. THE WINDS WILL REMAIN NORTHERLY
RESULTING IN OFFSHORE FLOW RESULTING IN DRIER CONDITIONS FOR THE
REST OF SOUTHWEST ALASKA THROUGH TUESDAY. THE NORTHERLY WINDS
WILL BRING IN COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES FOR THE EARLY PART OF THIS UPCOMING WEEK.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE EAST SIBERIAN HIGH WILL REMAIN IN PLACE RESULTING IN
NORTHERLY WINDS THROUGH THE BERING STRAIT SOUTHWARD INTO THE
NORTHERN BERING SEA THROUGH SUNDAY BEFORE SHIFTING TO THE
SOUTHEAST BY MONDAY. THIS WILL CONTINUE TO BRING SHOWERY
PRECIPITATION TO THE NORTHERN BERING SEA WITH COOLER TEMPERATURES
THROUGH SUNDAY. BY SUNDAY NIGHT A WEATHER FRONT WILL PUSH THROUGH
THE WESTERN ALEUTIANS INTO THE WESTERN TO CENTRAL BERING SEA BY
MONDAY...FOLLOWED BY A NORTH PACIFIC STORM FORCE LOW TRACKING
THROUGH SHEMYA BY MONDAY NIGHT BEFORE MOVING INTO THE WESTERN
BERING SEA BY TUESDAY. A SECONDARY WEATHER FRONT FROM THE
AFOREMENTIONED LOW WILL BE POSITIONED JUST WEST OF UNALASKA BY
TUESDAY MORNING. THIS WILL BRING WARMER TEMPERATURES WITH STORM
FORCE WINDS THROUGH THE WESTERN ALEUTIANS INTO THE SOUTHERN BERING
SEA. THE CENTRAL TO EASTERN ALEUTIANS WILL RECEIVE GALE FORCE
WINDS SPILLING OVER INTO THE CENTRAL BERING SEA BY TUESDAY. AS THE
NORTH PACIFIC LOW MOVES INTO THE BERING SEA BY TUESDAY...THIS WILL
PRODUCE A LARGE SWATH OF MOISTURE AND PRECIPITATION THROUGH THE
ALEUTIANS AND THE BERING SEA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 177 178
 HEAVY FREEZING SPRAY 180 181 185
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MMC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...KH




000
FXAK68 PAFC 211329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
429 AM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...

AN AREA OF LOW PRESSURE OVER THE NORTHERN GULF CONTINUES TO PUSH
TO THE WEST/NORTHWEST OF MIDDLETON ISLAND EARLY THIS MORNING.
THIS LOW PRESSURE SYSTEM HELD TOGETHER A BIT LONGER THAN EXPECTED
OVER THE PAST SEVERAL FORECAST RUNS...ALLOWING FOR A STRONGER
BARRIER JET OVER THE NORTHERN GULF AND A SLIGHTLY SLOWER WESTWARD
TRACK. WARM AIR ADVECTION ON THE BACKSIDE OF THE LOW RAPIDLY
WARMED THE NORTHERN GULF COAST (CORDOVA AREA) FROM THE MID 30S TO
THE MID 40S AND TRANSITIONED PRECIPITATION FROM SNOW TO RAIN.
SNOWFALL CONTINUES TO OVERSPREAD MUCH OF THE GULF COAST AND IS
PUSHING FURTHER INLAND OVER THE COPPER RIVER BASIN...ANCHORAGE AND
PARTS OF THE MAT-SU VALLEY. THE LONGWAVE TROUGH EXTENDING FROM THE
KAMCHATKA PENINSULA TO THE PACIFIC NORTHWEST COAST OF THE UNITED
STATES CONTINUES TO AMPLIFY AS A POTENT SHORTWAVE AND AN UPPER
LEVEL JET RANGING FROM 150 TO 160 KT HELPS DIG THE TROUGH FURTHER
SOUTH IN THE NORTH PACIFIC. WEAK SURFACE AND UPPER LEVEL BASED
RIDGING IS DEVELOPING OVER THE WESTERN BERING SEA EARLY THIS
MORNING WHICH HAS HELPED TO SHIFT THE REMNANTS OF A WEAK LOW JUST
SOUTH OF THE ALEUTIAN CHAIN INTO THE WESTERN GULF OF ALASKA. AN
EVEN MORE POTENT JET (POSSIBLY APPROACHING 200 KT) HAS BEGUN TO
SET UP OVER EAST ASIA AND HAS HELPED TO INTENSIFY A LOW OVER THE
KAMCHATKA PENINSULA THAT HAS BEGUN TO PUSH A FRONT TOWARD THE
WESTERN BERING SEA.

&&

.MODEL DISCUSSION...

THE 00Z AND 06Z NUMERICAL GUIDANCE WAS STRUGGLING TO INITIALIZE
THE LOW IN THE NORTHERN GULF PRESENTLY LOCATED NORTHWEST OF
MIDDLETON ISLAND. BASED ON SURFACE OBSERVATIONS AND A SCATTEROMETER
PASS AT 0510Z...IT APPEARS THE 00Z/06Z NAM HAS INITIALIZED THE
BEST...WITH THE ECMWF BEING TOO FAST AND THE GEM BEING WAY TOO
SLOW. THE GFS IS A HUGE OUTLIER WITH THE INITIALIZATION AS IT HAD
MORE OF A COMPLEX LOW FEATURE THAN AN ACTUAL CLOSED LOW.
HOWEVER...MODELS ARE IN GOOD AGREEMENT WITH SNOW CONTINUING ACROSS
MUCH OF SOUTHCENTRAL ALASKA THROUGH THE BEGINNING OF THE UPCOMING
WEEK...WITH SNOWFALL BECOMING MORE SHOWERY IN NATURE WITH SOME
ELEVATED INSTABILITY AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
PUSHING ACROSS THE AREA. THE NAM WAS UTILIZED FOR THE MOST PART
OVER THE EAST DOMAIN DUE TO BETTER INITIALIZATION.

OUT WEST...MODELS REMAIN IN VERY GOOD AGREEMENT WITH A WEAK
SURFACE AND UPPER LEVEL RIDGE MOVING FROM THE WESTERN BERING SEA
TO EASTERN BERING SEA DURING THE COURSE OF THE WEEK. MODEL
AGREEMENT BEGINS TO FALTER LATE MONDAY INTO TUESDAY AS A LOW
DEVELOPS TO THE WEST OF SHEMYA AND PUSHES INTO THE BERING SEA.
WHILE THE MODELS ARE IN SOMEWHAT AGREEMENT WITH STRENGTH AND
POSITION...THE STANDARD DEVIATION OF OVER 5 MB IS A BIT DISCONCERTING.
NEVERTHELESS...IT APPEARS STORM FORCE WINDS WILL BE LIKELY WITH A
RAPIDLY DEVELOPING LOW INTERACTING WITH A POTENT (180 KT TO 200
KT) JET STREAK. A MIX OF THE ECMWF AND NAM WAS UTILIZED OVER THE
WESTERN DOMAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE LOW IN THE NORTHERN GULF IS BRINGING IN ENOUGH MOISTURE FROM
THE SOUTH TO BRING LIGHT SNOW TO MANY LOCATIONS AROUND SOUTHCENTRAL.
HOWEVER...IN SOME PLACES ALONG THE NORTH GULF COAST IT REMAINS
WARM ENOUGH FOR RAIN. AS THE LOW TRACKS WEST INTO THE COOK INLET
AREA TODAY FLOW WILL BECOME MORE SOUTHERLY RESULTING IN A BETTER
CHANCE FOR SNOW SHOWERS FROM THE ANCHORAGE BOWL AREA INTO THE MAT-
SU VALLEY. THIS HIGHER CHANCE OF LIGHT SNOW WILL LAST THROUGH
TONIGHT BEFORE THE LOW WEAKENS AND MOVES SOUTH.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE REMNANTS OF A DISSIPATING LOW LOCATED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
THE ALASKA RANGE THROUGH MONDAY. THE WINDS WILL REMAIN NORTHERLY
RESULTING IN OFFSHORE FLOW RESULTING IN DRIER CONDITIONS FOR THE
REST OF SOUTHWEST ALASKA THROUGH TUESDAY. THE NORTHERLY WINDS
WILL BRING IN COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES FOR THE EARLY PART OF THIS UPCOMING WEEK.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE EAST SIBERIAN HIGH WILL REMAIN IN PLACE RESULTING IN
NORTHERLY WINDS THROUGH THE BERING STRAIT SOUTHWARD INTO THE
NORTHERN BERING SEA THROUGH SUNDAY BEFORE SHIFTING TO THE
SOUTHEAST BY MONDAY. THIS WILL CONTINUE TO BRING SHOWERY
PRECIPITATION TO THE NORTHERN BERING SEA WITH COOLER TEMPERATURES
THROUGH SUNDAY. BY SUNDAY NIGHT A WEATHER FRONT WILL PUSH THROUGH
THE WESTERN ALEUTIANS INTO THE WESTERN TO CENTRAL BERING SEA BY
MONDAY...FOLLOWED BY A NORTH PACIFIC STORM FORCE LOW TRACKING
THROUGH SHEMYA BY MONDAY NIGHT BEFORE MOVING INTO THE WESTERN
BERING SEA BY TUESDAY. A SECONDARY WEATHER FRONT FROM THE
AFOREMENTIONED LOW WILL BE POSITIONED JUST WEST OF UNALASKA BY
TUESDAY MORNING. THIS WILL BRING WARMER TEMPERATURES WITH STORM
FORCE WINDS THROUGH THE WESTERN ALEUTIANS INTO THE SOUTHERN BERING
SEA. THE CENTRAL TO EASTERN ALEUTIANS WILL RECEIVE GALE FORCE
WINDS SPILLING OVER INTO THE CENTRAL BERING SEA BY TUESDAY. AS THE
NORTH PACIFIC LOW MOVES INTO THE BERING SEA BY TUESDAY...THIS WILL
PRODUCE A LARGE SWATH OF MOISTURE AND PRECIPITATION THROUGH THE
ALEUTIANS AND THE BERING SEA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 177 178
 HEAVY FREEZING SPRAY 180 181 185
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MMC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...KH




000
FXAK68 PAFC 211329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
429 AM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...

AN AREA OF LOW PRESSURE OVER THE NORTHERN GULF CONTINUES TO PUSH
TO THE WEST/NORTHWEST OF MIDDLETON ISLAND EARLY THIS MORNING.
THIS LOW PRESSURE SYSTEM HELD TOGETHER A BIT LONGER THAN EXPECTED
OVER THE PAST SEVERAL FORECAST RUNS...ALLOWING FOR A STRONGER
BARRIER JET OVER THE NORTHERN GULF AND A SLIGHTLY SLOWER WESTWARD
TRACK. WARM AIR ADVECTION ON THE BACKSIDE OF THE LOW RAPIDLY
WARMED THE NORTHERN GULF COAST (CORDOVA AREA) FROM THE MID 30S TO
THE MID 40S AND TRANSITIONED PRECIPITATION FROM SNOW TO RAIN.
SNOWFALL CONTINUES TO OVERSPREAD MUCH OF THE GULF COAST AND IS
PUSHING FURTHER INLAND OVER THE COPPER RIVER BASIN...ANCHORAGE AND
PARTS OF THE MAT-SU VALLEY. THE LONGWAVE TROUGH EXTENDING FROM THE
KAMCHATKA PENINSULA TO THE PACIFIC NORTHWEST COAST OF THE UNITED
STATES CONTINUES TO AMPLIFY AS A POTENT SHORTWAVE AND AN UPPER
LEVEL JET RANGING FROM 150 TO 160 KT HELPS DIG THE TROUGH FURTHER
SOUTH IN THE NORTH PACIFIC. WEAK SURFACE AND UPPER LEVEL BASED
RIDGING IS DEVELOPING OVER THE WESTERN BERING SEA EARLY THIS
MORNING WHICH HAS HELPED TO SHIFT THE REMNANTS OF A WEAK LOW JUST
SOUTH OF THE ALEUTIAN CHAIN INTO THE WESTERN GULF OF ALASKA. AN
EVEN MORE POTENT JET (POSSIBLY APPROACHING 200 KT) HAS BEGUN TO
SET UP OVER EAST ASIA AND HAS HELPED TO INTENSIFY A LOW OVER THE
KAMCHATKA PENINSULA THAT HAS BEGUN TO PUSH A FRONT TOWARD THE
WESTERN BERING SEA.

&&

.MODEL DISCUSSION...

THE 00Z AND 06Z NUMERICAL GUIDANCE WAS STRUGGLING TO INITIALIZE
THE LOW IN THE NORTHERN GULF PRESENTLY LOCATED NORTHWEST OF
MIDDLETON ISLAND. BASED ON SURFACE OBSERVATIONS AND A SCATTEROMETER
PASS AT 0510Z...IT APPEARS THE 00Z/06Z NAM HAS INITIALIZED THE
BEST...WITH THE ECMWF BEING TOO FAST AND THE GEM BEING WAY TOO
SLOW. THE GFS IS A HUGE OUTLIER WITH THE INITIALIZATION AS IT HAD
MORE OF A COMPLEX LOW FEATURE THAN AN ACTUAL CLOSED LOW.
HOWEVER...MODELS ARE IN GOOD AGREEMENT WITH SNOW CONTINUING ACROSS
MUCH OF SOUTHCENTRAL ALASKA THROUGH THE BEGINNING OF THE UPCOMING
WEEK...WITH SNOWFALL BECOMING MORE SHOWERY IN NATURE WITH SOME
ELEVATED INSTABILITY AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
PUSHING ACROSS THE AREA. THE NAM WAS UTILIZED FOR THE MOST PART
OVER THE EAST DOMAIN DUE TO BETTER INITIALIZATION.

OUT WEST...MODELS REMAIN IN VERY GOOD AGREEMENT WITH A WEAK
SURFACE AND UPPER LEVEL RIDGE MOVING FROM THE WESTERN BERING SEA
TO EASTERN BERING SEA DURING THE COURSE OF THE WEEK. MODEL
AGREEMENT BEGINS TO FALTER LATE MONDAY INTO TUESDAY AS A LOW
DEVELOPS TO THE WEST OF SHEMYA AND PUSHES INTO THE BERING SEA.
WHILE THE MODELS ARE IN SOMEWHAT AGREEMENT WITH STRENGTH AND
POSITION...THE STANDARD DEVIATION OF OVER 5 MB IS A BIT DISCONCERTING.
NEVERTHELESS...IT APPEARS STORM FORCE WINDS WILL BE LIKELY WITH A
RAPIDLY DEVELOPING LOW INTERACTING WITH A POTENT (180 KT TO 200
KT) JET STREAK. A MIX OF THE ECMWF AND NAM WAS UTILIZED OVER THE
WESTERN DOMAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE LOW IN THE NORTHERN GULF IS BRINGING IN ENOUGH MOISTURE FROM
THE SOUTH TO BRING LIGHT SNOW TO MANY LOCATIONS AROUND SOUTHCENTRAL.
HOWEVER...IN SOME PLACES ALONG THE NORTH GULF COAST IT REMAINS
WARM ENOUGH FOR RAIN. AS THE LOW TRACKS WEST INTO THE COOK INLET
AREA TODAY FLOW WILL BECOME MORE SOUTHERLY RESULTING IN A BETTER
CHANCE FOR SNOW SHOWERS FROM THE ANCHORAGE BOWL AREA INTO THE MAT-
SU VALLEY. THIS HIGHER CHANCE OF LIGHT SNOW WILL LAST THROUGH
TONIGHT BEFORE THE LOW WEAKENS AND MOVES SOUTH.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE REMNANTS OF A DISSIPATING LOW LOCATED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
THE ALASKA RANGE THROUGH MONDAY. THE WINDS WILL REMAIN NORTHERLY
RESULTING IN OFFSHORE FLOW RESULTING IN DRIER CONDITIONS FOR THE
REST OF SOUTHWEST ALASKA THROUGH TUESDAY. THE NORTHERLY WINDS
WILL BRING IN COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES FOR THE EARLY PART OF THIS UPCOMING WEEK.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE EAST SIBERIAN HIGH WILL REMAIN IN PLACE RESULTING IN
NORTHERLY WINDS THROUGH THE BERING STRAIT SOUTHWARD INTO THE
NORTHERN BERING SEA THROUGH SUNDAY BEFORE SHIFTING TO THE
SOUTHEAST BY MONDAY. THIS WILL CONTINUE TO BRING SHOWERY
PRECIPITATION TO THE NORTHERN BERING SEA WITH COOLER TEMPERATURES
THROUGH SUNDAY. BY SUNDAY NIGHT A WEATHER FRONT WILL PUSH THROUGH
THE WESTERN ALEUTIANS INTO THE WESTERN TO CENTRAL BERING SEA BY
MONDAY...FOLLOWED BY A NORTH PACIFIC STORM FORCE LOW TRACKING
THROUGH SHEMYA BY MONDAY NIGHT BEFORE MOVING INTO THE WESTERN
BERING SEA BY TUESDAY. A SECONDARY WEATHER FRONT FROM THE
AFOREMENTIONED LOW WILL BE POSITIONED JUST WEST OF UNALASKA BY
TUESDAY MORNING. THIS WILL BRING WARMER TEMPERATURES WITH STORM
FORCE WINDS THROUGH THE WESTERN ALEUTIANS INTO THE SOUTHERN BERING
SEA. THE CENTRAL TO EASTERN ALEUTIANS WILL RECEIVE GALE FORCE
WINDS SPILLING OVER INTO THE CENTRAL BERING SEA BY TUESDAY. AS THE
NORTH PACIFIC LOW MOVES INTO THE BERING SEA BY TUESDAY...THIS WILL
PRODUCE A LARGE SWATH OF MOISTURE AND PRECIPITATION THROUGH THE
ALEUTIANS AND THE BERING SEA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 177 178
 HEAVY FREEZING SPRAY 180 181 185
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MMC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...KH




000
FXAK68 PAFC 211329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
429 AM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...

AN AREA OF LOW PRESSURE OVER THE NORTHERN GULF CONTINUES TO PUSH
TO THE WEST/NORTHWEST OF MIDDLETON ISLAND EARLY THIS MORNING.
THIS LOW PRESSURE SYSTEM HELD TOGETHER A BIT LONGER THAN EXPECTED
OVER THE PAST SEVERAL FORECAST RUNS...ALLOWING FOR A STRONGER
BARRIER JET OVER THE NORTHERN GULF AND A SLIGHTLY SLOWER WESTWARD
TRACK. WARM AIR ADVECTION ON THE BACKSIDE OF THE LOW RAPIDLY
WARMED THE NORTHERN GULF COAST (CORDOVA AREA) FROM THE MID 30S TO
THE MID 40S AND TRANSITIONED PRECIPITATION FROM SNOW TO RAIN.
SNOWFALL CONTINUES TO OVERSPREAD MUCH OF THE GULF COAST AND IS
PUSHING FURTHER INLAND OVER THE COPPER RIVER BASIN...ANCHORAGE AND
PARTS OF THE MAT-SU VALLEY. THE LONGWAVE TROUGH EXTENDING FROM THE
KAMCHATKA PENINSULA TO THE PACIFIC NORTHWEST COAST OF THE UNITED
STATES CONTINUES TO AMPLIFY AS A POTENT SHORTWAVE AND AN UPPER
LEVEL JET RANGING FROM 150 TO 160 KT HELPS DIG THE TROUGH FURTHER
SOUTH IN THE NORTH PACIFIC. WEAK SURFACE AND UPPER LEVEL BASED
RIDGING IS DEVELOPING OVER THE WESTERN BERING SEA EARLY THIS
MORNING WHICH HAS HELPED TO SHIFT THE REMNANTS OF A WEAK LOW JUST
SOUTH OF THE ALEUTIAN CHAIN INTO THE WESTERN GULF OF ALASKA. AN
EVEN MORE POTENT JET (POSSIBLY APPROACHING 200 KT) HAS BEGUN TO
SET UP OVER EAST ASIA AND HAS HELPED TO INTENSIFY A LOW OVER THE
KAMCHATKA PENINSULA THAT HAS BEGUN TO PUSH A FRONT TOWARD THE
WESTERN BERING SEA.

&&

.MODEL DISCUSSION...

THE 00Z AND 06Z NUMERICAL GUIDANCE WAS STRUGGLING TO INITIALIZE
THE LOW IN THE NORTHERN GULF PRESENTLY LOCATED NORTHWEST OF
MIDDLETON ISLAND. BASED ON SURFACE OBSERVATIONS AND A SCATTEROMETER
PASS AT 0510Z...IT APPEARS THE 00Z/06Z NAM HAS INITIALIZED THE
BEST...WITH THE ECMWF BEING TOO FAST AND THE GEM BEING WAY TOO
SLOW. THE GFS IS A HUGE OUTLIER WITH THE INITIALIZATION AS IT HAD
MORE OF A COMPLEX LOW FEATURE THAN AN ACTUAL CLOSED LOW.
HOWEVER...MODELS ARE IN GOOD AGREEMENT WITH SNOW CONTINUING ACROSS
MUCH OF SOUTHCENTRAL ALASKA THROUGH THE BEGINNING OF THE UPCOMING
WEEK...WITH SNOWFALL BECOMING MORE SHOWERY IN NATURE WITH SOME
ELEVATED INSTABILITY AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
PUSHING ACROSS THE AREA. THE NAM WAS UTILIZED FOR THE MOST PART
OVER THE EAST DOMAIN DUE TO BETTER INITIALIZATION.

OUT WEST...MODELS REMAIN IN VERY GOOD AGREEMENT WITH A WEAK
SURFACE AND UPPER LEVEL RIDGE MOVING FROM THE WESTERN BERING SEA
TO EASTERN BERING SEA DURING THE COURSE OF THE WEEK. MODEL
AGREEMENT BEGINS TO FALTER LATE MONDAY INTO TUESDAY AS A LOW
DEVELOPS TO THE WEST OF SHEMYA AND PUSHES INTO THE BERING SEA.
WHILE THE MODELS ARE IN SOMEWHAT AGREEMENT WITH STRENGTH AND
POSITION...THE STANDARD DEVIATION OF OVER 5 MB IS A BIT DISCONCERTING.
NEVERTHELESS...IT APPEARS STORM FORCE WINDS WILL BE LIKELY WITH A
RAPIDLY DEVELOPING LOW INTERACTING WITH A POTENT (180 KT TO 200
KT) JET STREAK. A MIX OF THE ECMWF AND NAM WAS UTILIZED OVER THE
WESTERN DOMAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE LOW IN THE NORTHERN GULF IS BRINGING IN ENOUGH MOISTURE FROM
THE SOUTH TO BRING LIGHT SNOW TO MANY LOCATIONS AROUND SOUTHCENTRAL.
HOWEVER...IN SOME PLACES ALONG THE NORTH GULF COAST IT REMAINS
WARM ENOUGH FOR RAIN. AS THE LOW TRACKS WEST INTO THE COOK INLET
AREA TODAY FLOW WILL BECOME MORE SOUTHERLY RESULTING IN A BETTER
CHANCE FOR SNOW SHOWERS FROM THE ANCHORAGE BOWL AREA INTO THE MAT-
SU VALLEY. THIS HIGHER CHANCE OF LIGHT SNOW WILL LAST THROUGH
TONIGHT BEFORE THE LOW WEAKENS AND MOVES SOUTH.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE REMNANTS OF A DISSIPATING LOW LOCATED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
THE ALASKA RANGE THROUGH MONDAY. THE WINDS WILL REMAIN NORTHERLY
RESULTING IN OFFSHORE FLOW RESULTING IN DRIER CONDITIONS FOR THE
REST OF SOUTHWEST ALASKA THROUGH TUESDAY. THE NORTHERLY WINDS
WILL BRING IN COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES FOR THE EARLY PART OF THIS UPCOMING WEEK.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE EAST SIBERIAN HIGH WILL REMAIN IN PLACE RESULTING IN
NORTHERLY WINDS THROUGH THE BERING STRAIT SOUTHWARD INTO THE
NORTHERN BERING SEA THROUGH SUNDAY BEFORE SHIFTING TO THE
SOUTHEAST BY MONDAY. THIS WILL CONTINUE TO BRING SHOWERY
PRECIPITATION TO THE NORTHERN BERING SEA WITH COOLER TEMPERATURES
THROUGH SUNDAY. BY SUNDAY NIGHT A WEATHER FRONT WILL PUSH THROUGH
THE WESTERN ALEUTIANS INTO THE WESTERN TO CENTRAL BERING SEA BY
MONDAY...FOLLOWED BY A NORTH PACIFIC STORM FORCE LOW TRACKING
THROUGH SHEMYA BY MONDAY NIGHT BEFORE MOVING INTO THE WESTERN
BERING SEA BY TUESDAY. A SECONDARY WEATHER FRONT FROM THE
AFOREMENTIONED LOW WILL BE POSITIONED JUST WEST OF UNALASKA BY
TUESDAY MORNING. THIS WILL BRING WARMER TEMPERATURES WITH STORM
FORCE WINDS THROUGH THE WESTERN ALEUTIANS INTO THE SOUTHERN BERING
SEA. THE CENTRAL TO EASTERN ALEUTIANS WILL RECEIVE GALE FORCE
WINDS SPILLING OVER INTO THE CENTRAL BERING SEA BY TUESDAY. AS THE
NORTH PACIFIC LOW MOVES INTO THE BERING SEA BY TUESDAY...THIS WILL
PRODUCE A LARGE SWATH OF MOISTURE AND PRECIPITATION THROUGH THE
ALEUTIANS AND THE BERING SEA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 177 178
 HEAVY FREEZING SPRAY 180 181 185
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MMC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...KH




000
FXAK68 PAFC 211329
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
429 AM AKST SUN DEC 21 2014

.ANALYSIS AND UPPER LEVELS...

AN AREA OF LOW PRESSURE OVER THE NORTHERN GULF CONTINUES TO PUSH
TO THE WEST/NORTHWEST OF MIDDLETON ISLAND EARLY THIS MORNING.
THIS LOW PRESSURE SYSTEM HELD TOGETHER A BIT LONGER THAN EXPECTED
OVER THE PAST SEVERAL FORECAST RUNS...ALLOWING FOR A STRONGER
BARRIER JET OVER THE NORTHERN GULF AND A SLIGHTLY SLOWER WESTWARD
TRACK. WARM AIR ADVECTION ON THE BACKSIDE OF THE LOW RAPIDLY
WARMED THE NORTHERN GULF COAST (CORDOVA AREA) FROM THE MID 30S TO
THE MID 40S AND TRANSITIONED PRECIPITATION FROM SNOW TO RAIN.
SNOWFALL CONTINUES TO OVERSPREAD MUCH OF THE GULF COAST AND IS
PUSHING FURTHER INLAND OVER THE COPPER RIVER BASIN...ANCHORAGE AND
PARTS OF THE MAT-SU VALLEY. THE LONGWAVE TROUGH EXTENDING FROM THE
KAMCHATKA PENINSULA TO THE PACIFIC NORTHWEST COAST OF THE UNITED
STATES CONTINUES TO AMPLIFY AS A POTENT SHORTWAVE AND AN UPPER
LEVEL JET RANGING FROM 150 TO 160 KT HELPS DIG THE TROUGH FURTHER
SOUTH IN THE NORTH PACIFIC. WEAK SURFACE AND UPPER LEVEL BASED
RIDGING IS DEVELOPING OVER THE WESTERN BERING SEA EARLY THIS
MORNING WHICH HAS HELPED TO SHIFT THE REMNANTS OF A WEAK LOW JUST
SOUTH OF THE ALEUTIAN CHAIN INTO THE WESTERN GULF OF ALASKA. AN
EVEN MORE POTENT JET (POSSIBLY APPROACHING 200 KT) HAS BEGUN TO
SET UP OVER EAST ASIA AND HAS HELPED TO INTENSIFY A LOW OVER THE
KAMCHATKA PENINSULA THAT HAS BEGUN TO PUSH A FRONT TOWARD THE
WESTERN BERING SEA.

&&

.MODEL DISCUSSION...

THE 00Z AND 06Z NUMERICAL GUIDANCE WAS STRUGGLING TO INITIALIZE
THE LOW IN THE NORTHERN GULF PRESENTLY LOCATED NORTHWEST OF
MIDDLETON ISLAND. BASED ON SURFACE OBSERVATIONS AND A SCATTEROMETER
PASS AT 0510Z...IT APPEARS THE 00Z/06Z NAM HAS INITIALIZED THE
BEST...WITH THE ECMWF BEING TOO FAST AND THE GEM BEING WAY TOO
SLOW. THE GFS IS A HUGE OUTLIER WITH THE INITIALIZATION AS IT HAD
MORE OF A COMPLEX LOW FEATURE THAN AN ACTUAL CLOSED LOW.
HOWEVER...MODELS ARE IN GOOD AGREEMENT WITH SNOW CONTINUING ACROSS
MUCH OF SOUTHCENTRAL ALASKA THROUGH THE BEGINNING OF THE UPCOMING
WEEK...WITH SNOWFALL BECOMING MORE SHOWERY IN NATURE WITH SOME
ELEVATED INSTABILITY AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
PUSHING ACROSS THE AREA. THE NAM WAS UTILIZED FOR THE MOST PART
OVER THE EAST DOMAIN DUE TO BETTER INITIALIZATION.

OUT WEST...MODELS REMAIN IN VERY GOOD AGREEMENT WITH A WEAK
SURFACE AND UPPER LEVEL RIDGE MOVING FROM THE WESTERN BERING SEA
TO EASTERN BERING SEA DURING THE COURSE OF THE WEEK. MODEL
AGREEMENT BEGINS TO FALTER LATE MONDAY INTO TUESDAY AS A LOW
DEVELOPS TO THE WEST OF SHEMYA AND PUSHES INTO THE BERING SEA.
WHILE THE MODELS ARE IN SOMEWHAT AGREEMENT WITH STRENGTH AND
POSITION...THE STANDARD DEVIATION OF OVER 5 MB IS A BIT DISCONCERTING.
NEVERTHELESS...IT APPEARS STORM FORCE WINDS WILL BE LIKELY WITH A
RAPIDLY DEVELOPING LOW INTERACTING WITH A POTENT (180 KT TO 200
KT) JET STREAK. A MIX OF THE ECMWF AND NAM WAS UTILIZED OVER THE
WESTERN DOMAIN.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...

THE LOW IN THE NORTHERN GULF IS BRINGING IN ENOUGH MOISTURE FROM
THE SOUTH TO BRING LIGHT SNOW TO MANY LOCATIONS AROUND SOUTHCENTRAL.
HOWEVER...IN SOME PLACES ALONG THE NORTH GULF COAST IT REMAINS
WARM ENOUGH FOR RAIN. AS THE LOW TRACKS WEST INTO THE COOK INLET
AREA TODAY FLOW WILL BECOME MORE SOUTHERLY RESULTING IN A BETTER
CHANCE FOR SNOW SHOWERS FROM THE ANCHORAGE BOWL AREA INTO THE MAT-
SU VALLEY. THIS HIGHER CHANCE OF LIGHT SNOW WILL LAST THROUGH
TONIGHT BEFORE THE LOW WEAKENS AND MOVES SOUTH.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...

THE REMNANTS OF A DISSIPATING LOW LOCATED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
THE ALASKA RANGE THROUGH MONDAY. THE WINDS WILL REMAIN NORTHERLY
RESULTING IN OFFSHORE FLOW RESULTING IN DRIER CONDITIONS FOR THE
REST OF SOUTHWEST ALASKA THROUGH TUESDAY. THE NORTHERLY WINDS
WILL BRING IN COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES FOR THE EARLY PART OF THIS UPCOMING WEEK.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...

THE EAST SIBERIAN HIGH WILL REMAIN IN PLACE RESULTING IN
NORTHERLY WINDS THROUGH THE BERING STRAIT SOUTHWARD INTO THE
NORTHERN BERING SEA THROUGH SUNDAY BEFORE SHIFTING TO THE
SOUTHEAST BY MONDAY. THIS WILL CONTINUE TO BRING SHOWERY
PRECIPITATION TO THE NORTHERN BERING SEA WITH COOLER TEMPERATURES
THROUGH SUNDAY. BY SUNDAY NIGHT A WEATHER FRONT WILL PUSH THROUGH
THE WESTERN ALEUTIANS INTO THE WESTERN TO CENTRAL BERING SEA BY
MONDAY...FOLLOWED BY A NORTH PACIFIC STORM FORCE LOW TRACKING
THROUGH SHEMYA BY MONDAY NIGHT BEFORE MOVING INTO THE WESTERN
BERING SEA BY TUESDAY. A SECONDARY WEATHER FRONT FROM THE
AFOREMENTIONED LOW WILL BE POSITIONED JUST WEST OF UNALASKA BY
TUESDAY MORNING. THIS WILL BRING WARMER TEMPERATURES WITH STORM
FORCE WINDS THROUGH THE WESTERN ALEUTIANS INTO THE SOUTHERN BERING
SEA. THE CENTRAL TO EASTERN ALEUTIANS WILL RECEIVE GALE FORCE
WINDS SPILLING OVER INTO THE CENTRAL BERING SEA BY TUESDAY. AS THE
NORTH PACIFIC LOW MOVES INTO THE BERING SEA BY TUESDAY...THIS WILL
PRODUCE A LARGE SWATH OF MOISTURE AND PRECIPITATION THROUGH THE
ALEUTIANS AND THE BERING SEA.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE
MARINE...GALE WARNING 177 178
 HEAVY FREEZING SPRAY 180 181 185
FIRE WEATHER...NONE

&&

$$

SYNOPSIS AND MODEL DISCUSSION...MMC
SOUTHCENTRAL ALASKA...DK
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PLD
LONG TERM...KH




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK69 PAFG 211227
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
327 AM AKST SUN DEC 21 2014

.DISCUSSION...
CURRENT RUNS OF THE GFS/NAM/ECMWF/CANADA NH MODELS ARE IN
GENERALLY GOOD AGREEMENT OUT THROUGH 12Z WED.

UPPER AIR...
ALL OF THE OPERATIONAL MODELS ARE GRADUALLY DEEPENING AN UPPER
TROUGH SOUTHEASTWARD OUT OF SIBERIA AND THE WESTERN ARCTIC OCEAN
THROUGH MON NIGHT...BRINGING A COLDER AIR MASS TO NORTHWEST ALASKA
AND THE NORTHERN PARTS OF THE WEST COAST. THIS MORNING...THE NAM
AND ECMWF ARE FOLLOWING THE LEAD OF THE GFS IN MOVING THE TROUGH
EASTWARD ACROSS THE NORTHERN HALF OF NORTHERN ALASKA THROUGH WED
EVENING...PULLING THE COLDER AIR MASS EASTWARD ACROSS THE
NORTHERN PARTS OF NORTHERN ALASKA.

A PROGRESSIVE UPPER LEVEL RIDGE IS EXPECTED TO BEGIN BUILDING
OVER THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS MON. BY
TUE AFTERNOON THE RIDGE WILL INCREASE CONSIDERABLY IN AMPLITUDE...
EXTENDING FROM EASTERN INTERIOR SIBERIA TO NUNIVAK ISLAND
AND THE ALASKA PENINSULA. BY WED AFTERNOON...THE RIDGE AXIS
WILL EXTENDING FROM THE NORTH COAST OF EASTERN SIBERIA TO
THE BERING STRAIT AND KODIAK ISLAND. A WEAK SHORT WAVE TROUGH
WILL MOVE THROUGH THE SOUTHERN PART OF THE RIDGE TUE NIGHT AND
WED AND LIKELY DAMPEN OUT ON WED. THIS FEATURE IS EXPECTED TO
HAVE LITTLE IF ANY IMPACT IN OUR FORECAST AREA. THE RIDGE
IS EXPECTED TO CONTINUE TO MOVE ACROSS NORTHERN ALASKA WED
AND THU AS A BROAD TROUGH SWINGS NORTHWARD ACROSS THE SOUTHERN
BERING SEA AND THE WEST COAST.

LATE THIS WEEK AND INTO THE WEEKEND...GEFS/NAEFS AND ECMWF
ENSEMBLE MEANS BUILDING A RIDGE OVER THE GULF OF ALASKA AND THE
ALASKA MAINLAND...BY SAT NIGHT THE MEAN RIDGE AXIS EXTENDS FROM
THE WESTERN ARCTIC OCEAN TO THE CENTRAL ARCTIC COAST THEN
SOUTHEASTWARD INTO THE NORTHERN PANHANDLE. SOUTH TO SOUTHWEST
ALOFT FLOW OVER THE NORTHERN ALASKA MAINLAND ON THE BACK SIDE OF
THE RIDGE WILL BRING IN WARMER AIR ALOFT AND AT THE SURFACE. THIS
TREND IS INDICATED IN GFS EXTENDED MOS TEMPERATURES AT MOST
FORECAST SITES TOWARDS THE END OF THE WEEK.

SURFACE...
THE BIGGEST SHORT TERM ISSUE IS WINDS OVER THE CENTRAL AND EASTERN
ARCTIC COAST AND INTERIOR ARCTIC SLOPE. THE 06Z MANUAL SURFACE
ANALYSIS INDICATED A NARROW TROUGH ALONG THE CENTRAL ARCTIC COAST
THEN TO SOUTH OF BARTER ISLAND...WITH A WEAK RIDGE OVER THE
INLAND ARCTIC COAST. THIS PATTERN IS RESULTING IN EASTERLY GALE
FORCE WINDS AT BARTER ISLAND AND MUCH LIGHTER WINDS FARTHER TO THE
WEST. THESE SURFACE FEATURES ARE GENERALLY NOT WELL HANDLED BY THE
MODELS...AND TEND TO BE MORE PERSISTENT THAN MODEL FORECASTS. AT
THIS TIME...LOOKING FOR THIS PATTERN TO HOLD TOGETHER TODAY THEN
BECOMING GRADUALLY SMOOTHED OUT WHICH SHOULD RESULT IN DECREASING
WINDS ALONG THE EASTERN ARCTIC COAST AND IN MARINE ZONE PKZ245.
WINDS ARE EXPECTED TO SHIFT TO LIGHT WESTERLY IN THIS AREA BY MON
WITH A WEAK SURFACE TROUGH PROGGED TO MOVE EASTWARD. IN ANY
EVENT...CONFIDENCE IN THE WIND FORECASTS IN THIS AREA IS BELOW
AVERAGE.

A TIGHT PINCH IN THE ISOBAR FIELD FROM THE NORTHWEST ALASKA CAPES
TO THE BERING STRAIT AND ST LAWRENCE ISLAND IS PRODUCING BRISK
NORTH TO NORTHEAST WINDS IN THESE AREAS...WITH GALE FORCE WINDS AT
TIN CITY AND GALE GUSTS AT POINT HOPE AND WALES. THIS TIGHT
GRADIENT IS EXPECTED TO GRADUALLY RELAX DURING THE NEXT 24
HOURS...RESULTING IN DECREASING WINDS.

LATE EVENING NASA/SPORT NIGHT MICROPHYSICS RGB IMAGE SHOWS
EXTENSIVE LOW STRATUS OVER THE ARCTIC COAST AND MUCH OF THE INLAND
ARCTIC COAST...WITH ONLY A FEW PATCHES ELSEWHERE IN THE INTERIOR.
PRESENCE OF THE STRATUS IN THESE AREAS IS WELL SUPPORTED BY
AVAILABLE SURFACE OBSERVATIONS.

SCATTERED SNOW SHOWERS OVER THE CENTRAL AND WESTERN ARCTIC
COAST AND OVER THE CHUKCHI AND NORTHERN BERING SEAS ARE
EXPECT TO SPREAD SLOWLY EASTWARD ACROSS THE NORTHERN PARTS
OF NORTHERN ALASKA THROUGH TUE AS THE COLD UPPER TROUGH
MARCHES SLOWLY EASTWARD. SCATTERED SNOW SHOWERS ARE EXPECTED
TO BREAK OUT OVER THE SOUTHERN AND EASTERN INTERIOR MON
NIGHT AND TUE.

BRISK EAST WINDS DEVELOPING OVER ST LAWRENCE ISLAND LATE TUE
AFTERNOON OR TUE EVENING...INCREASING TO GALE LATER TUE NIGHT AS A
WEATHER FRONT APPROACHES FROM THE SOUTH. EASTERLY GALES DEVELOPING
TUE IN THE EXTREME WESTERN PARTS OF MARINE ZONE PKZ210.


COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

GALE WARNING FOR PKZ245.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240.
&&

$$

RF DEC 14




000
FXAK68 PAFC 210122 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

CORRECTION TO ADD MARINE WARNING

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 127 177 178
         HEAVY FREEZING SPRAY 180 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH



000
FXAK68 PAFC 210122 CCA
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

CORRECTION TO ADD MARINE WARNING

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALES 127 177 178
         HEAVY FREEZING SPRAY 180 181 185.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH




000
FXAK68 PAFC 210122
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH




000
FXAK68 PAFC 210122
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH



000
FXAK68 PAFC 210122
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH



000
FXAK68 PAFC 210122
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH



000
FXAK68 PAFC 210122
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH



000
FXAK68 PAFC 210122
AFDAFC

SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ANCHORAGE AK
422 PM AKST SAT DEC 20 2014

.ANALYSIS AND UPPER LEVELS...
AS THE 49TH STATE ANTICIPATES THE PSYCHOLOGICALLY IMPORTANT
TURNING POINT OF GAINING DAYLIGHT TOMORROW...THE WEATHER MAP
ACROSS THE STATE IS STARTING TO LOOK A LITTLE MORE INTERESTING.
A BROAD AREA OF LOW PRESSURE REMAINS IN THE GULF...WITH NUMEROUS
SHORTWAVE TROUGHS PINWHEELING AROUND THE COMMON CENTER...AND THE
STRONGER WAVES ALSO HAVE A REFLECTION OF LOWER PRESSURES AT THE
SURFACE. ONE SUCH SHORTWAVE IS MOVING ACROSS THE NORTHERN GULF
TODAY...WITH AN ATTENDANT SURFACE LOW (ESTIMATED AROUND 969 MB)
DUE SOUTH OF CAPE SUCKLING. SHOWERS ACROSS THE NORTHERN GULF ARE
GIVING WAY TO A MORE STRATIFORM-LOOKING PRECIPITATION SHIELD AS
THE LOW MOVES INTO RADAR RANGE. THIS LOW...COMBINED WITH COLD AIR
IN PLACE OVER INTERIOR ALASKA...CONTINUES TO PRODUCE MODERATE DRY
NORTHERLY OFFSHORE WINDS FROM PRINCE WILLIAM SOUND TO THE KENAI
PENINSULA. AS RAIN/SNOW MOVE IN FROM THE GULF...THIS DRY AIR WILL
NEED TO BE MOISTENED UP IN ORDER FOR PRECIP TO REACH THE GROUND.

TO THE WEST...DRY OFFSHORE FLOW CONTINUES ACROSS THE SOUTHWEST
MAINLAND...WITH A PARTLY CLOUDY AND COLD DAY UNFOLDING FOR A GOOD
PORTION OF THE AREA. A WEAKENING AND VERTICALLY STACKED LOW
PRESSURE SYSTEM SOUTH OF THE DUTCH HARBOR AREA IS SLOWLY MOVING
OUT INTO THE PACIFIC...WITH THE MAIN IMPACT OF THIS FEATURE
CURRENTLY BEING SOME GUSTY NORTHERLY WINDS OVER THE WESTERN HALF
OF THE ALEUTIANS. MEANWHILE...ARCTIC AIR IS SPILLING DOWN FROM
THE BERING STRAIT ACROSS THE NORTHERN AND WESTERN BERING
SEA...KICKING OFF SOME SNOW SHOWER ACTIVITY AS IT EXPANDS
SOUTHWARD.

&&

.MODEL DISCUSSION...
THE OVERWHELMING FOCUS THROUGHOUT THE SHORT TERM (FIRST 2 DAYS)
FORECAST PERIOD IS THE EVOLUTION CURRENTLY UNFOLDING IN THE GULF
OF ALASKA AND SOUTHCENTRAL MAINLAND. AS MENTIONED IN PREVIOUS
DISCUSSIONS...THE MODEL CONSENSUS OVER THE LAST DAY OR TWO HAS
SHIFTED TOWARD A MORE NORTHWESTERLY TRACK OF THE DISTURBANCE
CURRENTLY EAST OF MIDDLETON ISLAND. CONFIDENCE CONTINUES TO
INCREASE THAT THIS FEATURE WILL WEAKEN AND TRACK INLAND TONIGHT SOMEWHERE
OVER THE NORTHERN KENAI PENINSULA. AS THIS HAPPENS...CROSS-BARRIER
FLOW WILL WEAKEN AND PRECIPITATION IS LIKELY TO SPREAD ACROSS
MUCH OF THE COOK INLET REGION. THE GFS AND GEM-REGIONAL BOTH
DEPART FROM THE CONSENSUS TRACK OVER THE NORTHERN KENAI (GEM-
REGIONAL TO THE NORTH AND GFS TO THE SOUTH) AND WERE NOT
CONSIDERED IN FORECAST PREPARATION TODAY. THAT LEAVES BASICALLY
THE ECMWF AND THE NAM...THOUGH EVEN THEY HAVE A TIMING ISSUE
REMAINING. THE ECMWF IS ABOUT 6 HOURS FASTER WITH LANDFALL THAN
THE NAM...ALTHOUGH THE 18Z NAM HAS CLOSED THAT GAP SLIGHTLY. A
MIDDAY SATELLITE SCATTEROMETER PASS HAS FORTUNATELY SAMPLED THE
CENTER OF CIRCULATION...AND LENDS SUPPORT LARGELY TO THE FASTER
ECMWF SOLUTION. OF NOTE ALSO IS THE FACT THAT SATELLITE IMAGERY
CLEARLY SUGGESTS TWO DISCRETE CENTERS OF CIRCULATION IN THE
NORTH/NORTHWEST GULF...RATHER THAN A SINGLE ELONGATED PRESSURE
CENTER. THE ECMWF IS THE ONLY MODEL TO DEPICT A TWO-LOW SOLUTION.
AS YOU MIGHT GUESS...THE ECMWF IS PREFERRED ACROSS THE ENTIRE
FORECAST DOMAIN TODAY...LARGELY DUE TO SUPERIOR PERFORMANCE ACROSS
THE GULF.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (DAYS 1 AND 2)...
A NICE WARM CONVEYOR BELT SHOWING UP ON RADAR SATELLITE TODAY
LOOKS TO BRING LIGHT SNOW TO MUCH OF THE REGION. THE
RESPONSIBLE LOW PRESSURE SYSTEM WILL MOVE INTO WESTERN PRINCE
WILLIAM SOUND TONIGHT THEN INLAND AS IT RAPIDLY WEAKENS. SNOW WILL
BEGIN TO MOVE INTO CORDOVA AND VALDEZ EARLY THIS EVENING THEN
WESTWARD OVER WHITTER AND SEWARD. ON THE WEST SIDE OF THE CHUGACH
SNOW WILL BEGIN AROUND MIDNIGHT AND CONTINUE INTO SUNDAY. THIS
LOOKS LIKE A HIGH PROBABILITY/LOW ACCUMULATION EVENT. THE HIGHEST
AMOUNTS LOOK TO FALL SOMEWHERE BETWEEN ANCHORAGE TO KENAI. ONCE
THE SYSTEM PASSES TOMORROW MORNING THE SOUTHCENTRAL WILL BE UNDER
THE INFLUENCE OF AN UNSTABLE REGIME ALOFT FOR THE NEXT COUPLE
DAYS. THE UNSTABLE FLOW COMBINED WITH WEAK DISTURBANCES WITHIN IT
MAKE FOR A LOW CONFIDENCE FORECAST. THE PROBABILITY FOR SNOW
SHOWERS IS QUIET HIGH WITHIN THIS REGIME BUT WHERE EXACTLY THEY
SET UP IS LESS CERTAIN. EXPECT SNOW AND RAIN SHOWERS ALONG THE
NORTH GULF COAST TOMORROW AND MONDAY WITH SCATTERED TO NUMEROUS
SNOW SHOWERS INLAND. TEMPERATURES WILL REMAIN AROUND NORMAL WITH
GENERALLY LIGHT WINDS.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (DAYS 1 AND 2)...
THE REMNANTS OF A WEAKENING LOW POSITIONED OVER KODIAK WILL
CONTINUE TO BRING SCATTERED SHOWERS ALONG THE ALEUTIAN RANGE AND
PARTS OF THE ALASKA PENINSULA THROUGH MONDAY. THE REST OF THE
SOUTHWEST MAINLAND WILL REMAIN UNDER DRIER OFFSHORE FLOW THROUGH
MONDAY. BY MONDAY MORNING AN UPPER LEVEL RIDGE WILL PUSH INTO THE
EASTERN BERING WHILE STEADILY AMPLIFYING. THIS SYNOPTIC FEATURE
COMBINED WITH THE COLD AIR FILTERING INTO THE REGION FROM THE
NORTH WILL BRING COOLER TEMPERATURES RESULTING IN BELOW NORMAL
TEMPERATURES THROUGH MONDAY.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (DAYS 1 AND 2)...
THE WEAKENING LOW JUST SOUTH OF THE CENTRAL ALEUTIANS CONTINUES TO
TRACK TO THE SOUTHEAST THIS EVENING...SLOWLY WEAKENING WINDS OVER
THE WESTERN AND CENTRAL ALEUTIANS/BERING. COLDER AIR BEHIND THIS
SYSTEM CONTINUES TO FILTER DOWN OVER PARTS OF THE WESTERN AND
CENTRAL ALEUTIANS/BERING THROUGH TOMORROW MORNING...KEEPING
SHOWERY CONDITIONS AND GUSTY WINDS IN THE FORECAST FOR THAT AREA.
A FRONTAL SYSTEM WILL BEGIN TO PUSH INTO THE WESTERN ALEUTIANS
FROM THE SOUTHWEST TOMORROW AFTERNOON...BRINGING ANOTHER ROUND OF
GALE FORCE SOUTHERLY WINDS AND A MIX OF RAIN AND SNOW OVER THE
WESTERN ALEUTIANS HEADING INTO MONDAY. WITH THIS SYSTEM BRINGING
IN SOME WARMER TEMPERATURES FROM THE NORTH PACIFIC...THE
PREDOMINANT PRECIPITATION TYPE WILL START OFF AS SNOW AND STEADILY
CHANGE TO RAIN BY MONDAY AFTERNOON.

&&

.LONG TERM FORECAST (DAYS 3 THROUGH 7)...
LOW PRESSURE REMAINS THE DOMINANT WEATHER PATTERN OVER THE BERING
THROUGH EARLY NEXT WEEKEND. MODELS HAVE NOT COME INTO BETTER
AGREEMENT ON THE UPPER LOW PLACEMENT IN THE WESTERN BERING ON
TUESDAY WHICH LEADS TO UNCERTAINTY THROUGH THE EXTENDED FORECAST.
THE GENERAL FOCUS WILL BE ALONG THE FRONT THAT MOVES FROM THE
CENTRAL BERING TO THE SOUTHWEST COAST TUESDAY INTO WEDNESDAY.
GUSTY GALE WINDS AND MIXED PRECIPITATION ACCOMPANY THE FRONT
ACROSS THE ALEUTIANS AND BERING WITH STORM FORCE WINDS EXPECTED
ACROSS THE WESTERN ALEUTIANS AS THE CENTER OF THE LOW MOVES NORTH
OF THE ALEUTIAN CHAIN. THE FRONT SLOWS IN PROGRESSION ON THURSDAY
AS IS PUSHES INTO THE MAINLAND AND ELONGATES ITS BOUNDARY EASTWARD
INTO THE GULF. A TRIPLE POINT LOW IS LIKELY TO DEVELOP IN THE
WESTERN GULF MID WEEK WITH AN EASTWARD PROPAGATION WHICH KEEPS MOST
OF THE PRECIPITATION ALONG THE GULF WATER AND SURROUNDING COAST.

&&


.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...NONE.
FIRE WEATHER...NONE.

&&

$$

SYNOPSIS AND MODEL DISCUSSION...AD
SOUTHCENTRAL ALASKA...ML
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...TP
LONG TERM...KH



000
FXAK67 PAJK 210109
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
409 PM AKST SAT DEC 20 2014

.SHORT TERM...YESTERDAYS LOW FROM THE SOUTHEAST GULF OF ALASKA HAS
WEAKENED AND MOVE NORTH-NORTHWEST PULLING BACK TOWARDS PRINCE
WILLIAM SOUND THROUGH SATURDAY WITH A SECONDARY SPINNER IN THE
CLOUD MOVING TO OFF CROSS SOUND. THE MAJORITY OF THE SHOWERS WITH
LOW HAVE EITHER MOVED WEST TOWARDS THE KENAI PENINSULA OR ARE
BEING LIFTED NORTH INTO PANHANDLE OR BRITISH COLUMBIA.

REALLY EASY TO SPOT THE JET STREAM BY THE FAST MOVING STREAM OF
CLOUDS FROM THE PACIFIC AIMED AT THE PACIFIC NORTHWEST OF THE
LOWER 48. ALONG THE NORTH SIDE OF THE JET STREAM SMALL VORTICITY
LOBES AND SHORT WAVES ARE SPREADING ENERGY AND SMALL LOWS TOWARDS
THE PANHANDLE. YET ANOTHER WILL BE USHERED INTO THE SOUTHEAST GULF
TO MOVE ACROSS THE SOUTHERN PANHANDLE ON SUNDAY MORNING. THIS
FEATURE IS NOT EXPECTED TO DEEPEN SIGNIFICANTLY BEFORE MAKING LAND
FALL SO JUST EXPECT SOME STRATIFORM RAIN TO SPREAD IN. WINDS
SHOULD STAY GENERALLY UNDER 25 KT ONCE THE WINDS DO SETTLE DOWN
THIS EVENING.

STILL HAVE AN EARLY EVENING GALE IN CROSS SOUND AND POSSIBLY
NORTHERN LYNN THIS EVENING BUT THEY SHOULD BE DIMINISHING TO SMALL
CRAFT LEVELS OR LESS BY THE MIDNIGHT TIME FRAME.

PRECIPITATION TYPE STILL THE TYPICAL FORECAST HEADACHE ACROSS THE
REGION. MOST AREAS WILL SEE RAIN WHILE THE FAR NORTH WILL LIKELY
BE SNOW EXCEPT NEAR THE MAIN CHANNELS. THE NORTH WINDS HOLDING THE
HAINES AND SKAGWAY AREAS IN THE COOL ENOUGH AIR TO LEAVE THAT IT AS
LIGHT SNOW. OVERALL THINK THE BEST DESCRIPTION FOR THE NORTH
PANHANDLE IS A HIGH POP AND LOW QPF SITUATION. AREAS ARE QUITE
LIKELY TO GET SOME RAIN OR SNOW BUT AMOUNTS WILL BE LIGHT.

CONFIDENCE IS AVERAGE WITH SHOWER PATTERN AND DIFFICULTIES OF
ALONG/SLIGHTLY OFFSHORE FLOW FOR THE NORTHERN AREAS.

.LONG TERM...POTENTIAL FOR A SIGNIFICANT LOW PRESSURE SYSTEM TO
IMPACT THE PANHANDLE EARLY NEXT WEEK THEN THE PATTERN BEGINS TO
CHANGE TOWARD THE END OF THE WEEK.

ONSHORE FLOW AND SHOWERS WILL BE ONGOING AT THE BEGINNING OF THE
EXTENDED PERIOD ON SUNDAY NIGHT. SHOWERS WILL DIMINISH DURING THE
DAY ON MONDAY AS OFFSHORE FLOW INCREASES IN ADVANCE OF A
STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST INTO THE
SOUTHEAST GULF. MODELS CONTINUE TO STRUGGLE WITH THIS FEATURE BUT
THE GFS HAS HAD GOOD RUN TO RUN CONTINUITY AND THE 12Z/18Z NAM
ALSO IS IN GOOD AGREEMENT WITH THE GFS. COMPLICATING MATTERS IS
THE 12Z ECMWF AND GEM WHO SPLIT THE ENERGY AND DEVELOP TWO LOW
CENTERS INSTEAD OF ONE STRONGER SYSTEM. DUE TO BETTER CONSISTENCY,
HAVE OPTED TO GO WITH THE GFS/NAM SOLUTION FOR THIS FORECAST
PACKAGE WHICH HAS RESULTED IN THE INTRODUCTION OF GALE FORCE WINDS
ACROSS THE SOUTHEAST GULF AND SOUTHERN INNER CHANNELS MONDAY NIGHT
INTO TUESDAY. BOTH THE NAM/GFS HAVE THIS STORM SYSTEM REACHING THE
UPPER 970`S BEFORE WEAKENING TUESDAY AS IT DRIFTS INLAND NEAR
CAPE DECISION. THE STRONGER SOLUTION WILL ALSO STRENGTHEN THE
NORTHERLY PRESSURE GRADIENT OVER THE NORTHERN HALF OF THE
PANHANDLE WITH SMALL CRAFT WINDS DEVELOPING DURING THIS TIME
FRAME. PRECIPITATION MAINLY IN THE FORM OF RAIN WILL SPREAD NORTH
MONDAY NIGHT AND TUESDAY BUT STRUGGLE TO MAKE IT INTO THE NORTHERN
PANHANDLE WITH STRONG OUTFLOW WINDS IN PLACE. WHILE PORTIONS OF
THE NORTHERN PANHANDLE WILL BE COLD ENOUGH FOR SNOW, EXPECT
PRECIP TO HAVE A HARD TIME MAKING IT THERE AND ANY PRECIP THAT
DOES FALL WILL BE ON THE LIGHTER SIDE. HEAVIEST PRECIP WILL BE IN
THE FORM OF RAIN ACROSS THE SOUTHERN HALF OF THE PANHANDLE.

UPPER TROUGH WEAKENS ACROSS THE AREA BY MID WEEK WITH A FEW
SMALLER IMPULSES IMPACTING THE PANHANDLE CHRISTMAS DAY AND FRIDAY.
IT STILL APPEARS A WEAKENING FRONTAL FEATURE WILL BRING PRECIP TO
THE PANHANDLE LATER CHRISTMAS DAY AND WITH A COOLER AIRMASS IN
PLACE THE LIKELIHOOD OF SNOW IS HIGHER WITH THIS SYSTEM THAN THE
PAST FEW WEEKS. THIS WILL CONTINUE TO BE MONITORED.

PATTERN CHANGE WILL RESULT IN RIDGING BEING THE DOMINANT FEATURE
OVER THE EASTERN GULF AND PANHANDLE BY NEXT WEEKEND. AS DISCUSSED
BY THE PREVIOUS SHIFT, MODELS CONTINUE TO STRUGGLE AS USUAL WITH
THE PATTERN CHANGE AND HOW IT WILL EVOLVE SO DETAILS WILL NEED TO
BE WORKED OUT IN FUTURE SHIFTS.

USED A BLEND OF THE 18Z NAM AND 12Z GFS THROUGH 84
HOURS THEN TRANSITIONED TO THE LATEST WPC GUIDANCE FOR THE
REMAINDER OF THE LONG RANGE. CONFIDENCE IS STILL LACKING ON THE
LOW PRESSURE SYSTEM MOVING INTO THE EASTERN GULF EARLY NEXT WEEK.
HOWEVER, CONFIDENCE IS INCREASING ON A PATTERN CHANGE BY LATE NEXT
WEEK BUT MODELS CONTINUE TO STRUGGLE WITH THE DETAILS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ018.
MARINE...GALE WARNING FOR PKZ022-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012-021-035-036-041-042.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK67 PAJK 210109
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
409 PM AKST SAT DEC 20 2014

.SHORT TERM...YESTERDAYS LOW FROM THE SOUTHEAST GULF OF ALASKA HAS
WEAKENED AND MOVE NORTH-NORTHWEST PULLING BACK TOWARDS PRINCE
WILLIAM SOUND THROUGH SATURDAY WITH A SECONDARY SPINNER IN THE
CLOUD MOVING TO OFF CROSS SOUND. THE MAJORITY OF THE SHOWERS WITH
LOW HAVE EITHER MOVED WEST TOWARDS THE KENAI PENINSULA OR ARE
BEING LIFTED NORTH INTO PANHANDLE OR BRITISH COLUMBIA.

REALLY EASY TO SPOT THE JET STREAM BY THE FAST MOVING STREAM OF
CLOUDS FROM THE PACIFIC AIMED AT THE PACIFIC NORTHWEST OF THE
LOWER 48. ALONG THE NORTH SIDE OF THE JET STREAM SMALL VORTICITY
LOBES AND SHORT WAVES ARE SPREADING ENERGY AND SMALL LOWS TOWARDS
THE PANHANDLE. YET ANOTHER WILL BE USHERED INTO THE SOUTHEAST GULF
TO MOVE ACROSS THE SOUTHERN PANHANDLE ON SUNDAY MORNING. THIS
FEATURE IS NOT EXPECTED TO DEEPEN SIGNIFICANTLY BEFORE MAKING LAND
FALL SO JUST EXPECT SOME STRATIFORM RAIN TO SPREAD IN. WINDS
SHOULD STAY GENERALLY UNDER 25 KT ONCE THE WINDS DO SETTLE DOWN
THIS EVENING.

STILL HAVE AN EARLY EVENING GALE IN CROSS SOUND AND POSSIBLY
NORTHERN LYNN THIS EVENING BUT THEY SHOULD BE DIMINISHING TO SMALL
CRAFT LEVELS OR LESS BY THE MIDNIGHT TIME FRAME.

PRECIPITATION TYPE STILL THE TYPICAL FORECAST HEADACHE ACROSS THE
REGION. MOST AREAS WILL SEE RAIN WHILE THE FAR NORTH WILL LIKELY
BE SNOW EXCEPT NEAR THE MAIN CHANNELS. THE NORTH WINDS HOLDING THE
HAINES AND SKAGWAY AREAS IN THE COOL ENOUGH AIR TO LEAVE THAT IT AS
LIGHT SNOW. OVERALL THINK THE BEST DESCRIPTION FOR THE NORTH
PANHANDLE IS A HIGH POP AND LOW QPF SITUATION. AREAS ARE QUITE
LIKELY TO GET SOME RAIN OR SNOW BUT AMOUNTS WILL BE LIGHT.

CONFIDENCE IS AVERAGE WITH SHOWER PATTERN AND DIFFICULTIES OF
ALONG/SLIGHTLY OFFSHORE FLOW FOR THE NORTHERN AREAS.

.LONG TERM...POTENTIAL FOR A SIGNIFICANT LOW PRESSURE SYSTEM TO
IMPACT THE PANHANDLE EARLY NEXT WEEK THEN THE PATTERN BEGINS TO
CHANGE TOWARD THE END OF THE WEEK.

ONSHORE FLOW AND SHOWERS WILL BE ONGOING AT THE BEGINNING OF THE
EXTENDED PERIOD ON SUNDAY NIGHT. SHOWERS WILL DIMINISH DURING THE
DAY ON MONDAY AS OFFSHORE FLOW INCREASES IN ADVANCE OF A
STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST INTO THE
SOUTHEAST GULF. MODELS CONTINUE TO STRUGGLE WITH THIS FEATURE BUT
THE GFS HAS HAD GOOD RUN TO RUN CONTINUITY AND THE 12Z/18Z NAM
ALSO IS IN GOOD AGREEMENT WITH THE GFS. COMPLICATING MATTERS IS
THE 12Z ECMWF AND GEM WHO SPLIT THE ENERGY AND DEVELOP TWO LOW
CENTERS INSTEAD OF ONE STRONGER SYSTEM. DUE TO BETTER CONSISTENCY,
HAVE OPTED TO GO WITH THE GFS/NAM SOLUTION FOR THIS FORECAST
PACKAGE WHICH HAS RESULTED IN THE INTRODUCTION OF GALE FORCE WINDS
ACROSS THE SOUTHEAST GULF AND SOUTHERN INNER CHANNELS MONDAY NIGHT
INTO TUESDAY. BOTH THE NAM/GFS HAVE THIS STORM SYSTEM REACHING THE
UPPER 970`S BEFORE WEAKENING TUESDAY AS IT DRIFTS INLAND NEAR
CAPE DECISION. THE STRONGER SOLUTION WILL ALSO STRENGTHEN THE
NORTHERLY PRESSURE GRADIENT OVER THE NORTHERN HALF OF THE
PANHANDLE WITH SMALL CRAFT WINDS DEVELOPING DURING THIS TIME
FRAME. PRECIPITATION MAINLY IN THE FORM OF RAIN WILL SPREAD NORTH
MONDAY NIGHT AND TUESDAY BUT STRUGGLE TO MAKE IT INTO THE NORTHERN
PANHANDLE WITH STRONG OUTFLOW WINDS IN PLACE. WHILE PORTIONS OF
THE NORTHERN PANHANDLE WILL BE COLD ENOUGH FOR SNOW, EXPECT
PRECIP TO HAVE A HARD TIME MAKING IT THERE AND ANY PRECIP THAT
DOES FALL WILL BE ON THE LIGHTER SIDE. HEAVIEST PRECIP WILL BE IN
THE FORM OF RAIN ACROSS THE SOUTHERN HALF OF THE PANHANDLE.

UPPER TROUGH WEAKENS ACROSS THE AREA BY MID WEEK WITH A FEW
SMALLER IMPULSES IMPACTING THE PANHANDLE CHRISTMAS DAY AND FRIDAY.
IT STILL APPEARS A WEAKENING FRONTAL FEATURE WILL BRING PRECIP TO
THE PANHANDLE LATER CHRISTMAS DAY AND WITH A COOLER AIRMASS IN
PLACE THE LIKELIHOOD OF SNOW IS HIGHER WITH THIS SYSTEM THAN THE
PAST FEW WEEKS. THIS WILL CONTINUE TO BE MONITORED.

PATTERN CHANGE WILL RESULT IN RIDGING BEING THE DOMINANT FEATURE
OVER THE EASTERN GULF AND PANHANDLE BY NEXT WEEKEND. AS DISCUSSED
BY THE PREVIOUS SHIFT, MODELS CONTINUE TO STRUGGLE AS USUAL WITH
THE PATTERN CHANGE AND HOW IT WILL EVOLVE SO DETAILS WILL NEED TO
BE WORKED OUT IN FUTURE SHIFTS.

USED A BLEND OF THE 18Z NAM AND 12Z GFS THROUGH 84
HOURS THEN TRANSITIONED TO THE LATEST WPC GUIDANCE FOR THE
REMAINDER OF THE LONG RANGE. CONFIDENCE IS STILL LACKING ON THE
LOW PRESSURE SYSTEM MOVING INTO THE EASTERN GULF EARLY NEXT WEEK.
HOWEVER, CONFIDENCE IS INCREASING ON A PATTERN CHANGE BY LATE NEXT
WEEK BUT MODELS CONTINUE TO STRUGGLE WITH THE DETAILS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ018.
MARINE...GALE WARNING FOR PKZ022-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012-021-035-036-041-042.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU







000
FXAK67 PAJK 210109
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
409 PM AKST SAT DEC 20 2014

.SHORT TERM...YESTERDAYS LOW FROM THE SOUTHEAST GULF OF ALASKA HAS
WEAKENED AND MOVE NORTH-NORTHWEST PULLING BACK TOWARDS PRINCE
WILLIAM SOUND THROUGH SATURDAY WITH A SECONDARY SPINNER IN THE
CLOUD MOVING TO OFF CROSS SOUND. THE MAJORITY OF THE SHOWERS WITH
LOW HAVE EITHER MOVED WEST TOWARDS THE KENAI PENINSULA OR ARE
BEING LIFTED NORTH INTO PANHANDLE OR BRITISH COLUMBIA.

REALLY EASY TO SPOT THE JET STREAM BY THE FAST MOVING STREAM OF
CLOUDS FROM THE PACIFIC AIMED AT THE PACIFIC NORTHWEST OF THE
LOWER 48. ALONG THE NORTH SIDE OF THE JET STREAM SMALL VORTICITY
LOBES AND SHORT WAVES ARE SPREADING ENERGY AND SMALL LOWS TOWARDS
THE PANHANDLE. YET ANOTHER WILL BE USHERED INTO THE SOUTHEAST GULF
TO MOVE ACROSS THE SOUTHERN PANHANDLE ON SUNDAY MORNING. THIS
FEATURE IS NOT EXPECTED TO DEEPEN SIGNIFICANTLY BEFORE MAKING LAND
FALL SO JUST EXPECT SOME STRATIFORM RAIN TO SPREAD IN. WINDS
SHOULD STAY GENERALLY UNDER 25 KT ONCE THE WINDS DO SETTLE DOWN
THIS EVENING.

STILL HAVE AN EARLY EVENING GALE IN CROSS SOUND AND POSSIBLY
NORTHERN LYNN THIS EVENING BUT THEY SHOULD BE DIMINISHING TO SMALL
CRAFT LEVELS OR LESS BY THE MIDNIGHT TIME FRAME.

PRECIPITATION TYPE STILL THE TYPICAL FORECAST HEADACHE ACROSS THE
REGION. MOST AREAS WILL SEE RAIN WHILE THE FAR NORTH WILL LIKELY
BE SNOW EXCEPT NEAR THE MAIN CHANNELS. THE NORTH WINDS HOLDING THE
HAINES AND SKAGWAY AREAS IN THE COOL ENOUGH AIR TO LEAVE THAT IT AS
LIGHT SNOW. OVERALL THINK THE BEST DESCRIPTION FOR THE NORTH
PANHANDLE IS A HIGH POP AND LOW QPF SITUATION. AREAS ARE QUITE
LIKELY TO GET SOME RAIN OR SNOW BUT AMOUNTS WILL BE LIGHT.

CONFIDENCE IS AVERAGE WITH SHOWER PATTERN AND DIFFICULTIES OF
ALONG/SLIGHTLY OFFSHORE FLOW FOR THE NORTHERN AREAS.

.LONG TERM...POTENTIAL FOR A SIGNIFICANT LOW PRESSURE SYSTEM TO
IMPACT THE PANHANDLE EARLY NEXT WEEK THEN THE PATTERN BEGINS TO
CHANGE TOWARD THE END OF THE WEEK.

ONSHORE FLOW AND SHOWERS WILL BE ONGOING AT THE BEGINNING OF THE
EXTENDED PERIOD ON SUNDAY NIGHT. SHOWERS WILL DIMINISH DURING THE
DAY ON MONDAY AS OFFSHORE FLOW INCREASES IN ADVANCE OF A
STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST INTO THE
SOUTHEAST GULF. MODELS CONTINUE TO STRUGGLE WITH THIS FEATURE BUT
THE GFS HAS HAD GOOD RUN TO RUN CONTINUITY AND THE 12Z/18Z NAM
ALSO IS IN GOOD AGREEMENT WITH THE GFS. COMPLICATING MATTERS IS
THE 12Z ECMWF AND GEM WHO SPLIT THE ENERGY AND DEVELOP TWO LOW
CENTERS INSTEAD OF ONE STRONGER SYSTEM. DUE TO BETTER CONSISTENCY,
HAVE OPTED TO GO WITH THE GFS/NAM SOLUTION FOR THIS FORECAST
PACKAGE WHICH HAS RESULTED IN THE INTRODUCTION OF GALE FORCE WINDS
ACROSS THE SOUTHEAST GULF AND SOUTHERN INNER CHANNELS MONDAY NIGHT
INTO TUESDAY. BOTH THE NAM/GFS HAVE THIS STORM SYSTEM REACHING THE
UPPER 970`S BEFORE WEAKENING TUESDAY AS IT DRIFTS INLAND NEAR
CAPE DECISION. THE STRONGER SOLUTION WILL ALSO STRENGTHEN THE
NORTHERLY PRESSURE GRADIENT OVER THE NORTHERN HALF OF THE
PANHANDLE WITH SMALL CRAFT WINDS DEVELOPING DURING THIS TIME
FRAME. PRECIPITATION MAINLY IN THE FORM OF RAIN WILL SPREAD NORTH
MONDAY NIGHT AND TUESDAY BUT STRUGGLE TO MAKE IT INTO THE NORTHERN
PANHANDLE WITH STRONG OUTFLOW WINDS IN PLACE. WHILE PORTIONS OF
THE NORTHERN PANHANDLE WILL BE COLD ENOUGH FOR SNOW, EXPECT
PRECIP TO HAVE A HARD TIME MAKING IT THERE AND ANY PRECIP THAT
DOES FALL WILL BE ON THE LIGHTER SIDE. HEAVIEST PRECIP WILL BE IN
THE FORM OF RAIN ACROSS THE SOUTHERN HALF OF THE PANHANDLE.

UPPER TROUGH WEAKENS ACROSS THE AREA BY MID WEEK WITH A FEW
SMALLER IMPULSES IMPACTING THE PANHANDLE CHRISTMAS DAY AND FRIDAY.
IT STILL APPEARS A WEAKENING FRONTAL FEATURE WILL BRING PRECIP TO
THE PANHANDLE LATER CHRISTMAS DAY AND WITH A COOLER AIRMASS IN
PLACE THE LIKELIHOOD OF SNOW IS HIGHER WITH THIS SYSTEM THAN THE
PAST FEW WEEKS. THIS WILL CONTINUE TO BE MONITORED.

PATTERN CHANGE WILL RESULT IN RIDGING BEING THE DOMINANT FEATURE
OVER THE EASTERN GULF AND PANHANDLE BY NEXT WEEKEND. AS DISCUSSED
BY THE PREVIOUS SHIFT, MODELS CONTINUE TO STRUGGLE AS USUAL WITH
THE PATTERN CHANGE AND HOW IT WILL EVOLVE SO DETAILS WILL NEED TO
BE WORKED OUT IN FUTURE SHIFTS.

USED A BLEND OF THE 18Z NAM AND 12Z GFS THROUGH 84
HOURS THEN TRANSITIONED TO THE LATEST WPC GUIDANCE FOR THE
REMAINDER OF THE LONG RANGE. CONFIDENCE IS STILL LACKING ON THE
LOW PRESSURE SYSTEM MOVING INTO THE EASTERN GULF EARLY NEXT WEEK.
HOWEVER, CONFIDENCE IS INCREASING ON A PATTERN CHANGE BY LATE NEXT
WEEK BUT MODELS CONTINUE TO STRUGGLE WITH THE DETAILS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ018.
MARINE...GALE WARNING FOR PKZ022-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012-021-035-036-041-042.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU






000
FXAK67 PAJK 210109
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
409 PM AKST SAT DEC 20 2014

.SHORT TERM...YESTERDAYS LOW FROM THE SOUTHEAST GULF OF ALASKA HAS
WEAKENED AND MOVE NORTH-NORTHWEST PULLING BACK TOWARDS PRINCE
WILLIAM SOUND THROUGH SATURDAY WITH A SECONDARY SPINNER IN THE
CLOUD MOVING TO OFF CROSS SOUND. THE MAJORITY OF THE SHOWERS WITH
LOW HAVE EITHER MOVED WEST TOWARDS THE KENAI PENINSULA OR ARE
BEING LIFTED NORTH INTO PANHANDLE OR BRITISH COLUMBIA.

REALLY EASY TO SPOT THE JET STREAM BY THE FAST MOVING STREAM OF
CLOUDS FROM THE PACIFIC AIMED AT THE PACIFIC NORTHWEST OF THE
LOWER 48. ALONG THE NORTH SIDE OF THE JET STREAM SMALL VORTICITY
LOBES AND SHORT WAVES ARE SPREADING ENERGY AND SMALL LOWS TOWARDS
THE PANHANDLE. YET ANOTHER WILL BE USHERED INTO THE SOUTHEAST GULF
TO MOVE ACROSS THE SOUTHERN PANHANDLE ON SUNDAY MORNING. THIS
FEATURE IS NOT EXPECTED TO DEEPEN SIGNIFICANTLY BEFORE MAKING LAND
FALL SO JUST EXPECT SOME STRATIFORM RAIN TO SPREAD IN. WINDS
SHOULD STAY GENERALLY UNDER 25 KT ONCE THE WINDS DO SETTLE DOWN
THIS EVENING.

STILL HAVE AN EARLY EVENING GALE IN CROSS SOUND AND POSSIBLY
NORTHERN LYNN THIS EVENING BUT THEY SHOULD BE DIMINISHING TO SMALL
CRAFT LEVELS OR LESS BY THE MIDNIGHT TIME FRAME.

PRECIPITATION TYPE STILL THE TYPICAL FORECAST HEADACHE ACROSS THE
REGION. MOST AREAS WILL SEE RAIN WHILE THE FAR NORTH WILL LIKELY
BE SNOW EXCEPT NEAR THE MAIN CHANNELS. THE NORTH WINDS HOLDING THE
HAINES AND SKAGWAY AREAS IN THE COOL ENOUGH AIR TO LEAVE THAT IT AS
LIGHT SNOW. OVERALL THINK THE BEST DESCRIPTION FOR THE NORTH
PANHANDLE IS A HIGH POP AND LOW QPF SITUATION. AREAS ARE QUITE
LIKELY TO GET SOME RAIN OR SNOW BUT AMOUNTS WILL BE LIGHT.

CONFIDENCE IS AVERAGE WITH SHOWER PATTERN AND DIFFICULTIES OF
ALONG/SLIGHTLY OFFSHORE FLOW FOR THE NORTHERN AREAS.

.LONG TERM...POTENTIAL FOR A SIGNIFICANT LOW PRESSURE SYSTEM TO
IMPACT THE PANHANDLE EARLY NEXT WEEK THEN THE PATTERN BEGINS TO
CHANGE TOWARD THE END OF THE WEEK.

ONSHORE FLOW AND SHOWERS WILL BE ONGOING AT THE BEGINNING OF THE
EXTENDED PERIOD ON SUNDAY NIGHT. SHOWERS WILL DIMINISH DURING THE
DAY ON MONDAY AS OFFSHORE FLOW INCREASES IN ADVANCE OF A
STRENGTHENING LOW PRESSURE SYSTEM MOVING NORTHEAST INTO THE
SOUTHEAST GULF. MODELS CONTINUE TO STRUGGLE WITH THIS FEATURE BUT
THE GFS HAS HAD GOOD RUN TO RUN CONTINUITY AND THE 12Z/18Z NAM
ALSO IS IN GOOD AGREEMENT WITH THE GFS. COMPLICATING MATTERS IS
THE 12Z ECMWF AND GEM WHO SPLIT THE ENERGY AND DEVELOP TWO LOW
CENTERS INSTEAD OF ONE STRONGER SYSTEM. DUE TO BETTER CONSISTENCY,
HAVE OPTED TO GO WITH THE GFS/NAM SOLUTION FOR THIS FORECAST
PACKAGE WHICH HAS RESULTED IN THE INTRODUCTION OF GALE FORCE WINDS
ACROSS THE SOUTHEAST GULF AND SOUTHERN INNER CHANNELS MONDAY NIGHT
INTO TUESDAY. BOTH THE NAM/GFS HAVE THIS STORM SYSTEM REACHING THE
UPPER 970`S BEFORE WEAKENING TUESDAY AS IT DRIFTS INLAND NEAR
CAPE DECISION. THE STRONGER SOLUTION WILL ALSO STRENGTHEN THE
NORTHERLY PRESSURE GRADIENT OVER THE NORTHERN HALF OF THE
PANHANDLE WITH SMALL CRAFT WINDS DEVELOPING DURING THIS TIME
FRAME. PRECIPITATION MAINLY IN THE FORM OF RAIN WILL SPREAD NORTH
MONDAY NIGHT AND TUESDAY BUT STRUGGLE TO MAKE IT INTO THE NORTHERN
PANHANDLE WITH STRONG OUTFLOW WINDS IN PLACE. WHILE PORTIONS OF
THE NORTHERN PANHANDLE WILL BE COLD ENOUGH FOR SNOW, EXPECT
PRECIP TO HAVE A HARD TIME MAKING IT THERE AND ANY PRECIP THAT
DOES FALL WILL BE ON THE LIGHTER SIDE. HEAVIEST PRECIP WILL BE IN
THE FORM OF RAIN ACROSS THE SOUTHERN HALF OF THE PANHANDLE.

UPPER TROUGH WEAKENS ACROSS THE AREA BY MID WEEK WITH A FEW
SMALLER IMPULSES IMPACTING THE PANHANDLE CHRISTMAS DAY AND FRIDAY.
IT STILL APPEARS A WEAKENING FRONTAL FEATURE WILL BRING PRECIP TO
THE PANHANDLE LATER CHRISTMAS DAY AND WITH A COOLER AIRMASS IN
PLACE THE LIKELIHOOD OF SNOW IS HIGHER WITH THIS SYSTEM THAN THE
PAST FEW WEEKS. THIS WILL CONTINUE TO BE MONITORED.

PATTERN CHANGE WILL RESULT IN RIDGING BEING THE DOMINANT FEATURE
OVER THE EASTERN GULF AND PANHANDLE BY NEXT WEEKEND. AS DISCUSSED
BY THE PREVIOUS SHIFT, MODELS CONTINUE TO STRUGGLE AS USUAL WITH
THE PATTERN CHANGE AND HOW IT WILL EVOLVE SO DETAILS WILL NEED TO
BE WORKED OUT IN FUTURE SHIFTS.

USED A BLEND OF THE 18Z NAM AND 12Z GFS THROUGH 84
HOURS THEN TRANSITIONED TO THE LATEST WPC GUIDANCE FOR THE
REMAINDER OF THE LONG RANGE. CONFIDENCE IS STILL LACKING ON THE
LOW PRESSURE SYSTEM MOVING INTO THE EASTERN GULF EARLY NEXT WEEK.
HOWEVER, CONFIDENCE IS INCREASING ON A PATTERN CHANGE BY LATE NEXT
WEEK BUT MODELS CONTINUE TO STRUGGLE WITH THE DETAILS.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 6 PM AKST THIS EVENING FOR AKZ018.
MARINE...GALE WARNING FOR PKZ022-043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ012-021-035-036-041-042.

&&

$$

BEZENEK/TPS

VISIT US AT HTTP://WWW.WEATHER.GOV/JUNEAU






000
FXAK69 PAFG 202059
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1159 AM AKST SAT DEC 20 2014

.DISCUSSION...
DETERMINISTIC GUIDANCE ARE GENERALLY IN GOOD AGREEMENT WITH THE
LARGE SCALE PATTERN OUT TO 60-72 HRS. CONCERNS TODAY INCLUDE
MODERATE WINDS ACROSS THE BERING SEA/BERING STRAIT AND
COASTS...WITH GUSTS UP TO 40 MPH BEING OBSERVED AT TIMES AT POINT
HOPE...GAMBELL...AND CAPE ROMANZOFF. THE STRONGEST OF WHICH IS
BEING RECORED NEAR POINT HOPE.

ALSO FOG/STRATUS IS OBSERVED OVER THE NORTH SLOPE AND PORTIONS OF
THE INTERIOR AND WEST COAST THIS MORNING. FOG/STRATUS IS DEPICTED
FAIRLY WELL BY THE NASA SPORT NIGHTTIME MICROPHYSICS IMAGERY THIS
MORNING. IMAGERY SHOWS FOG/STRATUS CONFINED GENERALLY TO THE NORTH
SLOPE...NORTHERN HALF OF THE WEST COAST ZONES...AND OVER SMALL
SECTIONS OF THE AK INTERIOR. OBS INDICATE MAINLY STRATUS IN THE
INTERIOR...WITH FOG MORE PREVALENT OVER THE NORTH SLOPE.

.ALOFT...

BROAD 500 HPA LONGWAVE TROUGH IS POSITIONED OVER THE WESTERN TWO-
THIRDS OF AK WITH A RIDGE OVER NORTHERN AK. RIDGE IS POSITIONED
ACROSS THE NORTHWEST TERRITORIES AND YUKON. TROUGH WILL STAY
RELATIVE STATIONARY IN LOCATION WHILE WEAKENING THE NEXT 48 HRS AS
THE PATTERN ALOFT BECOMES MORE PROGRESSIVE. A RIDGE CURRENTLY JUST
SOUTH OF KAMCHATKA PENINSULA WILL BUILD AND MOVE EAST TOWARD THE
MIDDLE OF THE ALEUTIAN ISLANDS BY EARLY MON. RIDGE THEN MOVES EAST
INTO THE EASTERN ALEUTIAN ISLANDS BY EARLY TUE...THIS IS WHERE
DIFFERENCES START TO BECOME MORE APPARENT IN THE LARGE SCALE
PATTERN.

GFS BECOMES MORE BULLISH WITH THE 500 HPA TROUGH WHILE IT LIFTS
THE TROUGH NORTH ABOUT 60 HRS OUT LATE MON/EARLY TUE.
WHEREIN...THE TROUGH BASE BECOMES TILTED MORE NEGATIVE AT THIS
POINT AS WELL. 500 HPA HEIGHT FALLS OF AROUND 15-25 DAM ARE SEEN
IN THE GFS AND NAM COMPARED TO LESSER HEIGHT FALLS IN THE ECMWF.
THIS TRANSLATES TO A MORE COMPACT SFC LOW ON THE NAM AND GFS LATE
MON...COMPARED TO THE ECMWF...THAT WILL BE MOVING NORTHEAST INTO
SE AK EARLY TUE. GUIDANCE ARE SIMILAR IN MOVING THE TROUGH EAST
ACROSS MUCH OF NORTHERN AK BY THU...WITH THE GFS KEEPING THE
TROUGH STRONGER IN AMPLITUDE AND FARTHER SOUTH COMPARED TO THE
ECMWF.

MEANWHILE...COLDER AIR WILL BEGIN TO PENETRATE THE WEST COAST MON
AS THE TROUGH BEGINS TO LIFT NORTH. GFS IS A BIT COLDER AND MORE
BULLISH WITH HOW FAR THE COLD AIR PENETRATES INTO NORTHERN AK
HOWEVER...DIFFERENCES BETWEEN THE ECMWF ARE NOT THAT
GREAT...GENERALLY 3 TO 5 C.

.SURFACE...

A BROAD SFC LOW EXISTS SOUTH OF MAINLAND ALASKA AND THE ALEUTIAN
ISLANDS WITH MULTIPLE CENTERS ANALYZED...THE STRONGEST ABOUT 927
MB. THIS AREA OF LOW PRESSURE WILL WEAKEN AND BECOME MORE COMPACT
THE NEXT 48 HRS OVER THE GULF OF ALASKA. A NEW SFC LOW DEVELOPS IN
THE NORTHERN PACIFIC AS THE MID-LEVEL TROUGH ALOFT LIFTS NORTH AND
BECOMES MORE NEGATIVELY TILTED AT ITS BASE...BEGINNING ABOUT 54
HRS OUT. AS THE SFC LOW MOVES NORTHEAST INTO SE ALASKA TUE...LOW
PRESSURE WILL BEGIN BUILDING INTO THE INTERIOR.

HIGH PRESSURE CURRENTLY ACROSS THE ARCTIC OCEAN WILL MOVE INTO
THE CANADIAN ARCHIPELAGO BY MON. MEANWHILE...HIGH PRESSURE ACROSS
EASTERN SIBERIA WILL SPREAD INTO BERING AND CHUKCHI SEA AS WELL.

GUIDANCE ARE IN FAIR AGREEMENT WITH LOW PRESSURE DEVELOPING IN
THE WESTERN BERING SEA LATE MON/EARLY TUE. OUTSIDE OF A TROUGH OF
LOW PRESSURE EXTENDING FROM THE SFC LOW MOVING NORTH INTO NORTHERN
ALASKA...ITS CENTER IS NOT EXPECTED TO MOVE EAST MUCH BY WED.

WINDS ARE EXPECTED TO STAY ELEVATED OVER THE BERING SEA-BERING
STRAIT-EXTREME SOUTHERN END OF CHUKCHI SEA THE NEXT 36 HOURS AS
THE GRADIENT STAYS STRONG THERE. LOCAL WINDS...TANANA VALLEY
JET AND WINDS OVER THE NE YUKON FLATS...SHOULD BEGIN TO RELAX THE
NEXT 24 HRS AS LOW PRESSURE IN THE GULF OF ALASKA WEAKENS.

IN REGARD TO PRECIPITATION...DRY CONDITIONS EXPECT OVER THE NEXT
24 HRS OVER INTERIOR AK...WITH FLURRIES OR SNOW SHOWERS EXPECT
OVER THE NORTH SLOPE AND THE WEST COAST. A FEW SHORT-WAVE TROUGHS
WITH MODERATE VORT MAXES WILL TRAVERSE THE NORTH SLOPE...WEST
COAST...AND WESTERN INTERIOR MON AND PROVIDE INCREASE CHANCES FOR
SNOW. INCREASE CHANCES FOR SNOW ARE EXPECTED ON TUE OVER THE REST
OF THE INTERIOR AS THE AFOREMENTIONED 500 HPA TROUGH ALOFT BEGINS
TO LIFT AND MOVE EAST ACROSS NORTHERN AK.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240-PKZ245.
&&

$$

ET DEC 14



000
FXAK69 PAFG 202059
AFDAFG

NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
1159 AM AKST SAT DEC 20 2014

.DISCUSSION...
DETERMINISTIC GUIDANCE ARE GENERALLY IN GOOD AGREEMENT WITH THE
LARGE SCALE PATTERN OUT TO 60-72 HRS. CONCERNS TODAY INCLUDE
MODERATE WINDS ACROSS THE BERING SEA/BERING STRAIT AND
COASTS...WITH GUSTS UP TO 40 MPH BEING OBSERVED AT TIMES AT POINT
HOPE...GAMBELL...AND CAPE ROMANZOFF. THE STRONGEST OF WHICH IS
BEING RECORED NEAR POINT HOPE.

ALSO FOG/STRATUS IS OBSERVED OVER THE NORTH SLOPE AND PORTIONS OF
THE INTERIOR AND WEST COAST THIS MORNING. FOG/STRATUS IS DEPICTED
FAIRLY WELL BY THE NASA SPORT NIGHTTIME MICROPHYSICS IMAGERY THIS
MORNING. IMAGERY SHOWS FOG/STRATUS CONFINED GENERALLY TO THE NORTH
SLOPE...NORTHERN HALF OF THE WEST COAST ZONES...AND OVER SMALL
SECTIONS OF THE AK INTERIOR. OBS INDICATE MAINLY STRATUS IN THE
INTERIOR...WITH FOG MORE PREVALENT OVER THE NORTH SLOPE.

.ALOFT...

BROAD 500 HPA LONGWAVE TROUGH IS POSITIONED OVER THE WESTERN TWO-
THIRDS OF AK WITH A RIDGE OVER NORTHERN AK. RIDGE IS POSITIONED
ACROSS THE NORTHWEST TERRITORIES AND YUKON. TROUGH WILL STAY
RELATIVE STATIONARY IN LOCATION WHILE WEAKENING THE NEXT 48 HRS AS
THE PATTERN ALOFT BECOMES MORE PROGRESSIVE. A RIDGE CURRENTLY JUST
SOUTH OF KAMCHATKA PENINSULA WILL BUILD AND MOVE EAST TOWARD THE
MIDDLE OF THE ALEUTIAN ISLANDS BY EARLY MON. RIDGE THEN MOVES EAST
INTO THE EASTERN ALEUTIAN ISLANDS BY EARLY TUE...THIS IS WHERE
DIFFERENCES START TO BECOME MORE APPARENT IN THE LARGE SCALE
PATTERN.

GFS BECOMES MORE BULLISH WITH THE 500 HPA TROUGH WHILE IT LIFTS
THE TROUGH NORTH ABOUT 60 HRS OUT LATE MON/EARLY TUE.
WHEREIN...THE TROUGH BASE BECOMES TILTED MORE NEGATIVE AT THIS
POINT AS WELL. 500 HPA HEIGHT FALLS OF AROUND 15-25 DAM ARE SEEN
IN THE GFS AND NAM COMPARED TO LESSER HEIGHT FALLS IN THE ECMWF.
THIS TRANSLATES TO A MORE COMPACT SFC LOW ON THE NAM AND GFS LATE
MON...COMPARED TO THE ECMWF...THAT WILL BE MOVING NORTHEAST INTO
SE AK EARLY TUE. GUIDANCE ARE SIMILAR IN MOVING THE TROUGH EAST
ACROSS MUCH OF NORTHERN AK BY THU...WITH THE GFS KEEPING THE
TROUGH STRONGER IN AMPLITUDE AND FARTHER SOUTH COMPARED TO THE
ECMWF.

MEANWHILE...COLDER AIR WILL BEGIN TO PENETRATE THE WEST COAST MON
AS THE TROUGH BEGINS TO LIFT NORTH. GFS IS A BIT COLDER AND MORE
BULLISH WITH HOW FAR THE COLD AIR PENETRATES INTO NORTHERN AK
HOWEVER...DIFFERENCES BETWEEN THE ECMWF ARE NOT THAT
GREAT...GENERALLY 3 TO 5 C.

.SURFACE...

A BROAD SFC LOW EXISTS SOUTH OF MAINLAND ALASKA AND THE ALEUTIAN
ISLANDS WITH MULTIPLE CENTERS ANALYZED...THE STRONGEST ABOUT 927
MB. THIS AREA OF LOW PRESSURE WILL WEAKEN AND BECOME MORE COMPACT
THE NEXT 48 HRS OVER THE GULF OF ALASKA. A NEW SFC LOW DEVELOPS IN
THE NORTHERN PACIFIC AS THE MID-LEVEL TROUGH ALOFT LIFTS NORTH AND
BECOMES MORE NEGATIVELY TILTED AT ITS BASE...BEGINNING ABOUT 54
HRS OUT. AS THE SFC LOW MOVES NORTHEAST INTO SE ALASKA TUE...LOW
PRESSURE WILL BEGIN BUILDING INTO THE INTERIOR.

HIGH PRESSURE CURRENTLY ACROSS THE ARCTIC OCEAN WILL MOVE INTO
THE CANADIAN ARCHIPELAGO BY MON. MEANWHILE...HIGH PRESSURE ACROSS
EASTERN SIBERIA WILL SPREAD INTO BERING AND CHUKCHI SEA AS WELL.

GUIDANCE ARE IN FAIR AGREEMENT WITH LOW PRESSURE DEVELOPING IN
THE WESTERN BERING SEA LATE MON/EARLY TUE. OUTSIDE OF A TROUGH OF
LOW PRESSURE EXTENDING FROM THE SFC LOW MOVING NORTH INTO NORTHERN
ALASKA...ITS CENTER IS NOT EXPECTED TO MOVE EAST MUCH BY WED.

WINDS ARE EXPECTED TO STAY ELEVATED OVER THE BERING SEA-BERING
STRAIT-EXTREME SOUTHERN END OF CHUKCHI SEA THE NEXT 36 HOURS AS
THE GRADIENT STAYS STRONG THERE. LOCAL WINDS...TANANA VALLEY
JET AND WINDS OVER THE NE YUKON FLATS...SHOULD BEGIN TO RELAX THE
NEXT 24 HRS AS LOW PRESSURE IN THE GULF OF ALASKA WEAKENS.

IN REGARD TO PRECIPITATION...DRY CONDITIONS EXPECT OVER THE NEXT
24 HRS OVER INTERIOR AK...WITH FLURRIES OR SNOW SHOWERS EXPECT
OVER THE NORTH SLOPE AND THE WEST COAST. A FEW SHORT-WAVE TROUGHS
WITH MODERATE VORT MAXES WILL TRAVERSE THE NORTH SLOPE...WEST
COAST...AND WESTERN INTERIOR MON AND PROVIDE INCREASE CHANCES FOR
SNOW. INCREASE CHANCES FOR SNOW ARE EXPECTED ON TUE OVER THE REST
OF THE INTERIOR AS THE AFOREMENTIONED 500 HPA TROUGH ALOFT BEGINS
TO LIFT AND MOVE EAST ACROSS NORTHERN AK.

COASTAL HAZARD POTENTIAL DAYS 3 AND 4...NONE

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
HEAVY FREEZING SPRAY WARNING FOR PKZ210.

SMALL CRAFT ADVISORY FOR PKZ210.

BRISK WIND ADVISORY FOR PKZ220-PKZ225-PKZ240-PKZ245.
&&

$$

ET DEC 14




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