FXAK67 PAJK 211453

AFDAJK



SOUTHEAST ALASKA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE JUNEAU AK

553 AM AKST WED NOV 21 2012



.SHORT TERM...SOMEWHAT COMPLICATED PATTERN IN THE GULF AND

NORTHEAST PACIFIC THIS MORNING. THERE ARE AROUND 4 SEPARATE

CIRCULATION CENTERS VISIBLE ON IR AND VIIRS NIGHTTIME VISIBLE

IMAGES. THE STRONGEST IS WEST OF DIXON ENTRANCE CURRENTLY AND IS

SLOWLY WEAKENING AS IT REMAINS NEARLY STATIONARY. A SECOND LOW

IS JUST SE OF KODIAK ISLAND, A THIRD IS AROUND 50N 140W, AND THE

FOURTH IS A VERY WEAK ONE OVER HAIDA GWAII. THEY ARE RESPONSIBLE

FOR THE SHOWERS THAT ARE OVER THE SOUTHERN INNER CHANNELS AT THE

MOMENT. KETCHIKAN AND ANNETTE HAVE BEEN REPORTING RAIN MOST OF THE

MORNING AND THE RADAR SHOWS SOME SHOWERS AROUND SOUTHERN BARANOF

ISLAND AS WELL. PRECIP AMOUNTS HAVE BEEN LIGHT FOR THE MOST PART.

THESE FEATURES WILL CONTINUE TO WEAKEN OVER THE NEXT 12 TO 18

HOURS AS A DEVELOPING LOW IN THE NORTH CENTRAL GULF BEGINS TO

SPREAD ITS INFLUENCE INTO THE GULF.



ALSO AFFECTING THE AREA IS A STRONG HIGH PRESSURE SYSTEM IN THE

YUKON THAT ALONG WITH THE LOWS IN THE GULF ARE CAUSING STRONG COLD

OUTFLOW WINDS OVER MOST OF THE NORTHERN PANHANDLE. HAINES, SKAGWAY

AND JUNEAU ARE STILL UNDER STRONG WIND HEADLINES DUE TO THIS FOR

THE MORNING AND MOST NORTHERN INNER CHANNELS HAVE EITHER GALE

WARNINGS OR SMALL CRAFT ADVISORIES. THE WINDS IN JUNEAU ARE MAINLY

DUE TO A MODERATE TAKU WIND EVENT THAT PEAKED LAST NIGHT WITH

GUSTS TO 45 TO 50 KT AT SOUTH DOUGLAS AND THE FEDERAL BUILDING. THESE

WINDS SHOULD DIMINISH THROUGH THE DAY AS THE LOWS IN THE GULF

WEAKEN AWAY AND CROSS BARRIER FLOW DIMINISHES.



THINGS START TO GET INTERESTING LATE TONIGHT AS WE START TO GET

MORE INFLUENCE FROM THE DEVELOPING STRONG STORM IN THE NORTHERN

PACIFIC. BY 12Z THURS THE LOW WILL HAVE DROPPED TO 970 MB AND BE

AROUND 50N 145W. THE ASSOCIATED FRONT WILL BE MOVING NORTH THROUGH

THE NIGHT BUT WILL STILL BE SOUTH OF THE AREA BY LATE TONIGHT. THE

WINDS HOWEVER WILL NOT. I AM EXPECTING E TO SE WIND UP TO STORM

FORCE FOR THE SOUTHERN OUTER MARINE ZONE BY LATE TONIGHT AND GALES

FOR THE REST OF THE SOUTHERN INNER CHANNELS AND OUTER MARINE

ZONES. ON LAND, GUSTS COULD BE REACHING INTO THE 50 TO 60 MPH

RANGE BY LATE TONIGHT.



AS FOR PRECIP NOT MUCH IS EXPECTED YET. THE MAIN RAIN BANDS WILL

STILL BE SOUTH OF THE AREA BY LATE TONIGHT BUT SOME SHOWERS COULD

STILL REMAIN OVER THE PANHANDLE FROM THE NOW DISSIPATED LOWS THAT

WERE OVER THE AREA TODAY AS WELL AS FROM ANY WEAKER PRE-FRONTAL

BANDS. MOST OF THE PRECIP WILL BE OVER THE SOUTH AS THE NORTHERLY

OUTFLOW AND DRY COLD AIR OVER THE NORTH WILL INHIBIT THE PRECIP

FROM MAKING IT INTO THE NORTHERN HALF OF THE PANHANDLE. AS FOR

TYPE BARANOF ISLAND, PRINCE OF WALES, AND AREAS SOUTH OF WRANGELL

WILL BE WARM ENOUGH FOR RAIN WITH MAYBE SOME SNOW MIXED IN AT

TIMES. NORTH OF THESE AREAS WILL SEE SNOW BUT ANY ACCUMULATIONS

WILL BE LIGHT IF PRECIP FALLS AT ALL.



SHORT RANGE MODELS WERE IN DECENT AGREEMENT FOR THE PERIOD. NAM

SEEMED TO HAVE THE BEST AGREEMENT WITH THE VARIOUS FEATURES THAT

WERE PRESENT OUT IN THE GULF THIS MORNING SO MAIN GUIDANCE WAS IN

THAT DIRECTION. GFS WAS A CLOSE SECOND, WHILE THE EC LAGGED BEHIND

DUE TO IT REPRESENTING THE FEATURES AS A LITTLE TOO WEAK. FORECAST

CONFIDENCE IS ABOUT AVERAGE. 









&&



.LONG TERM...A POWERFUL LOW IS EXPECTED DEVELOP AND MOVE TO THE

SOUTHERN GULF ON THURSDAY. THE WEATHER FRONT AND VERY STRONG WINDS

WILL MOVE ACROSS THE SOUTHEAST GULF WATERS EARLY THURSDAY MORNING

AND THE SOUTHERN HALF OF THE PANHANDLE DURING THE DAY. LOOKING FOR

60+ KT WINDS FOR PORTIONS OF THE GULF... AND POTENTIALLY GUSTS OF

6O TO 80 MPH OR MORE TO IMPACT THE PRINCE OF WALES ISLAND NORTH TO

SOUTHERN BARANOF ISLAND. 



THE LOW POSITION AND STRENGTH OF THE LOW IS LEADING TO STRONG

CROSS BARRIER FLOW IN THE JUNEAU AREA THAT IS FAVORABLE TO TAKU

LIKE WINDS FOR THURSDAY IN THE DOWNTOWN JUNEAU AREA AND DOUGLAS.



AS THE FRONT MOVES NORTH ON THURSDAY THE PRECIPITATION WILL HAVE

TO OVERCOME DOWNSLOPE CONDITIONS IN THE CENTRAL AND NORTHERN

PANHANDLE. ANOTHER ISSUE IS HOW MUCH WARMING WILL BE GOING ON AND

IMPACTING THE PRECIPITATION TYPE.  



THE SOUTHERN PORTION OF THE PANHANDLE WILL NEED TO WATCH FOR

FRIDAY AS WELL AS THE LOW APPROACHES PRINCE OF WALES ISLAND

ANOTHER BATCH OF GUSTY WINDS WILL LIKELY AFFECT THEM THE AS WELL.

AFTER THAT THE LOW WEAKENS MORE AND SLIDES EAST LEAVING RESIDUAL

SHOWERS THROUGH THE WEEKEND AND ANOTHER SYSTEM TRYING TO SPREAD

EARLY NEXT WEEK. CONFIDENCE IS FAIRLY GOOD TO ABOUT SATURDAY AND

THEN FALLS OFF TO AVERAGE OR SLIGHTLY LESS FOR EARLY NEXT WEEK. 





.AJK WATCHES/WARNINGS/ADVISORIES...

PUBLIC...HIGH WIND WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON FOR 

     AKZ023-026>028.

         STRONG WIND UNTIL 9 AM AKST THIS MORNING FOR AKZ025.

         HIGH WIND WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING 

     FOR AKZ025.

         STRONG WIND LATE TONIGHT FOR AKZ029.

         STRONG WIND UNTIL NOON AKST TODAY FOR AKZ018-019.

MARINE...STORM WARNING FOR PKZ012-041. 

         GALE WARNING FOR PKZ011-013-021-022-031-033-035-036-042-043. 

         SMALL CRAFT ADVISORY FOR PKZ032-034-051-052. 



&&



$$



EAL/BEZENEK










FXAK67 PAJK 031351

AFDAJK



SOUTHEAST ALASKA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE JUNEAU AK

551 AM AKDT TUE SEP 3 2013



.SHORT TERM...TWO STORIES FOR THIS SHIFT, THE SURFACE RIDGE

FIRMLY PLACED OVER THE SOUTHERN, CENTRAL, AND INTERIOR PANHANDLE

ALLOWING THE STABLE SURFACE LAYER TO SATURATE INTO RADIATIONAL

FOG. THIS OCCURRED SOMEWHAT LATER THAN SUNDAY NIGHT. THE

METEOROLOGY ASSOCIATED WITH FOG SEEMED SOUND OVER THE SOUTH WITH

NE'ER A CLOUD IN THE SKIES, LIGHT WINDS, AND THE DYNAMICS ALOFT

ASSOCIATED WITH A FRONT MILES AWAY. A DENSE FOG ADVISORY WAS

ISSUED FOR THE MORNING PACKAGE FOR THE SOUTHERN AREAS AS

MODIS-VIIRS MICROPHYSICS IMAGE AND AIRPORT OBSERVATIONS WERE

CLEARLY INDICATING AREAS OF DENSE FOG. THE NORTHERN AND CENTRAL

AREAS WERE A TOUGHER CALL. THE ORIGINAL FEELING THAT

STRATOCUMULUS IN THE AREA AND HIGHER CLOUDS MAY LIMIT SURFACE

RADIATION. YET WITH STILL SOME MOISTURE IN THE AIR CONTRIBUTED

FROM A LOW TIDE SITUATION AS WELL AS RESIDUAL LEFT ON THE GROUND

FROM THIS WEEKEND'S RAIN TOTALS, AND AN APPARENT MORE BROKEN

LAYER OF STRATOCU ABOVE, AREAS NEAR JUNEAU, WRANGELL, PETERSBURG,

AND POSSIBLY KAKE ARE SHOWING SIGNS OF DENSE FOG. AN EXPANDED

AREA OF DENSE FOG WAS JUST ISSUED TO COVER THESE AREAS THROUGH

10 AM. STILL INCLUDED PATCHY FOG FOR LATE TONIGHT FOR THE

SOUTHERN ZONES, AS THE FRONT WILL TAKE ITS TIME MOVING EAST AND

SOUTH.  



 THE SECOND STORY IS THE APPROACHING FRONT MOVING INTO THE

EASTERN GULF. YAKUTAT IS ALREADY RAINING AND THEIR WINDS HAVE

SLOWLY BEGUN TO COME UP FROM THE EAST. WINDS AT BUOY 82 ARE

APPROACHING GALE FORCE AND THESE WINDS WILL STRETCH INTO THE

OFFSHORE WATERS AHEAD OF THE FRONT BEFORE WEAKENING TO SMALL

CRAFT THIS AFTERNOON. YAKUTAT BAY WILL ALSO GO TO SMALL CRAFT

THIS AFTERNOON INTO THIS EVENING. MODEL SOUNDINGS INDICATE SOME

HEALTHY WIND SHEAR AT 2000 FEET WITH THIS FRONT LASTING ALMOST

12 HOURS BEGINNING THIS AFTERNOON. WE ARE EXPECTING A WALL OF

RAIN TO REACH YAKUTAT WITH A COUPLE OF INCHES OF RAIN NOT OUT OF

THE QUESTION TODAY WITH AN ADDITION INCH OR INCH AND A HALF

TONIGHT. RAIN WILL BEGIN DEVELOPING TONIGHT FOR THE NORTHERN

PANHANDLE. TIMING SKETCHY, BUT FEEL MOST LIKELY IT WILL BE AFTER

MIDNIGHT FOR JUNEAU AND NORTHERN BARANOF ISLAND...BEGINNING

EARLIER FROM SKAGWAY DOWN TO CROSS SOUND. REGARDING INSIDE WATER

WINDS, DID GO SMALL CRAFT LATE TONIGHT FOR CROSS SOUND AND FEEL

NORTHERN LYNN WILL REACH SMALL CRAFT BY THIS AFTERNOON AND ONLY

INCREASE THROUGH THE NIGHT AS THE FRONT SWINGS IN FROM THE WEST

AND LEESIDE TROUGHING DEVELOPS IN THE YUKON.  



 MODELS OF CHOICE WAS ECMWF/GFS WITH SREF USED FOR POP FIELDS.

CONFIDENCE IN FORECAST HIGHER THAN AVERAGE.  



.LONG TERM...MAIN FOCUS FOR LONGER RANGE WAS THE LATE WEEK SYSTEM

MOVING N INTO THE GULF. MODELS AGREE IN GENERAL THAT A LOW WILL

TRACK N TOWARD KODIAK ISLAND WITH AN OCCLUDED FRONT OVER THE

CENTRAL GULF. FLOW ALOFT LOOKS SLY AND UPPER RIDGE APPEARS TO BE

FURTHER W THAN IT WILL BE WITH THE MIDWEEK FRONT...SO THE BULK OF

THE PRECIP SHOULD BE ALONG THE NRN GULF COAST. MAIN FORECAST

CHANGE WAS TO INCREASE WINDS FOR FRI-FRI NIGHT PERIODS OVER THE

GULF. USED BLEND OF 00Z GFS AND ECMWF FOR WED-FRI NIGHT...THEN

BASICALLY KEPT IN OR ADJUSTED TO WPC FOR SAT ONWARD...DEPENDING ON

WHAT WAS THERE PREVIOUSLY.



 FIRST FRONT SHOULD REACH THE CENTRAL OUTER COAST LATE WED...THEN

STALL THERE WHILE WEAKENING. IT LOOKS LIKE IT WILL DISSIPATE BY

LATE THU AFTERNOON. ONE TRICKY ASPECT WITH THIS FRONT IS HOW FAST

PRECIP AHEAD OF IT DIMINISHES AS THE FRONT WEAKENS. THE MODEL

BLEND WAS A MIDDLE GROUND COMPROMISE ON THIS...DIMINISHING THE

PRECIP DURING THE DAY THU. PRECIP WILL BE DIMINISHING OVER THE NE

GULF COAST WED MORNING...BUT ONSHORE FLOW WILL KEEP SOME PRECIP

GOING INTO WED NIGHT. THE FAR SERN AREA STILL LOOKS LIKE IT WILL

REMAIN DRY...MAINLY FROM PAKT/PANT EWD WED INTO THU. LYNN CANAL

WILL SEE THE MOST WIND OUT OF THIS SYSTEM...WITH GALES EXPECTED

OVER NRN LYNN CANAL WED AFTERNOON. PAGY MAY NEED STRONG WIND

HEADLINES FOR WED INTO WED EVENING AS WELL...BUT WILL HOLD OFF

FOR NOW AS THAT IS A 3RD-4TH PERIOD EVENT. 



 LOOKS LIKE GALES FOR A GOOD PART OF THE GULF FOR FRI AS NEXT

SYSTEM ROLLS IN. ENDED UP LOWERING SEAS FROM INITIAL GUIDANCE

FROM AKWAVE AND OUTSIDE WATERS TOOL AS WFO PAFC DID NOT WANT TO

JUMP THE SEAS UP AS MUCH AS I HAD INITIALLY...UP TO 20-22 FT IN

THE CENTRAL GULF...BUT IF MODELS CONTINUE HANDLING SYSTEM LIKE

THEY ARE...LATER SHIFTS WILL HAVE TO RAISE SEAS DUE TO THE FAIRLY

LONG SLY FETCH. 



 AFTER SAT MODELS DIVERGE SOMEWHAT SO GOING THE WPC ROUTE WAS THE

BEST WAY TO GO FOR NOW. 



.AJK WATCHES/WARNINGS/ADVISORIES...

PUBLIC...DENSE FOG ADVISORY UNTIL 10 AM AKDT THIS MORNING FOR AKZ025>029.

MARINE...GALE WARNING FOR PKZ052. 

         SMALL CRAFT ADVISORY FOR PKZ012-013-022-042-043-051-053. 



&&



$$



JWA/RWT










FXAK67 PAJK 151412

AFDAJK



SOUTHEAST ALASKA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE JUNEAU AK

612 AM AKDT TUE OCT 15 2013



.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS THE CENTRAL AND

SOUTHERN PANHANDLE UNDER PARTLY CLOUDY TO MOSTLY CLEAR WITH

PATCHY FOG WITH THE DEPARTING FRONT OVER CANADA. THERE IS A DENSE

FOG ADVISORY OUT FOR WESTERN POW AND OVER THE CENTRAL INNER

CHANNELS OUT UNTIL 9 AM. THERE IS SOME FOG OVER THE AREA AS SEEN

BY MODIS- VIIRS NIGHT MICROPHYSICS IMAGERY BUT IT IS NOT REDUCING

VISIBILITIES TO LESS THAN 1/4 OF A MILE AT THIS TIME. THE FOG MAY

BE THICKER IN PLACES THAT WILL MOVE OVER THE LAND AREAS ALSO AS

THE SUN RISES THE FOG MAY THICKEN UP. SO DID NOT CHANGE THAT

PORTION OF THE FORECAST AS WILL WAIT TO SEE SOME VISUAL

CONFIRMATION THEN DECIDE IF TO CANCEL THE ADVISORY. 



 THE NORTHERN HALF OF SE AK ARE SEEING MID-LEVEL CLOUDS WITH SOME

SCATTERED SHOWERS MOVE OVER THE AREA FROM THE WEST. THESE SHOWERS

ARE ASSOCIATED FROM A WEAK UPPER TROF THAT WILL MOVE INTO CANADA

EARLY THIS EVENING. THE NORTHERN GULF WILL SEE THE SHOWERS

INCREASE THROUGH TODAY FROM THE WEST BUT THEN DECREASE THIS

EVENING AND TONIGHT AS THE PRECIP RETREATS TO THE WEST.  



 A UPPER RIDGE WILL BUILD FROM THE SOUTH OVER THE GULF AND

PANHANDLE LATE THIS AFTERNOON INTO TONIGHT. THE UPPER AND MID-

LEVEL FLOW WILL INCREASE FROM THE NORTHWEST AND THE CLOUDS WILL

THIN FROM SOUTH TO NORTH THROUGH TONIGHT. AREAS OF FOG WILL

DEVELOP OVER MOST AREA OVER THE INNER CHANNELS THROUGH TONIGHT

WITH GOOD RADIATIVE COOLING.  



 THE WINDS ACROSS THE AREA ARE GENERALLY LESS THAN 10 MPH THIS

MORNING AND WILL REMAIN THAT WAY THROUGH THE SHORT TERM PERIOD

WITH A WEAK PRESSURE GRADIENT. THERE IS SOME INCREASED WINDS NEAR

SKAGWAY BUT BY TONIGHT THEY TOO WILL DIMINISH. THERE WILL BE SOME

INCREASED NORTHWEST WINDS OVER THE FAR SOUTHERN MARINE AREAS FROM

THE BUILDING RIDGE WHICH WILL PERSIST INTO TONIGHT. LYNN CANAL

CONTINUES TO BLOW MIN SMALL CRAFT FROM THE SOUTH THIS MORNING

WITH 15 KT OVER SOUTHERN LYNN. THESE WINDS WILL VERY SLOW

DECREASE THIS EVENING TO 15 KT OVER NORTHERN LYNN AND TO 10 KT

OVER SOUTHERN LYNN. 



 OVERALL THERE IS GOOD MODEL AGREEMENT AND RUN TO RUN CONSISTENCY

THAT THERE IS ABOVE AVERAGE FORECASTER CONFIDENCE. USED A BLEND

OF THE EC AND NAM FOR THE SHORT TERM FORECAST. 



.LONG TERM...FORECAST ON TRACK WITH UPPER LEVEL RIDGE OVER

SOUTHEAST ALASKA MIDWEEK, THEN NUDGING TO THE EAST AS A SOUTHERN

BERING SEA LOW PUSHES EAST INTO THE WEEKEND. AS THE RIDGE IS EXITS

INTO WESTERN CANADA, MOIST SOUTHWEST FLOW BRINGING RAIN TO THE

NORTHEAST GULF ON FRIDAY AND LIKELY INTO THE PANHANDLE FOR THE

REST OF THE WEEKEND AND INTO EARLY NEXT WEEK.



 THE BIGGEST ISSUES FOR TONIGHT'S SHIFT WAS FOG PLACEMENT AND SKY

COVER. SURE, WIND DIRECTIONS THROUGH COMPLEX TERRAIN UNDERNEATH A

SURFACE RIDGE WILL ALWAYS BE A CHALLENGE. ASIDE FROM LYNN CANAL

AND CLARENCE STRAIT, MOST PLACES WILL ENJOY LIGHT WINDS 10 KT OR

LESS. A GREAT DAY TO SAIL. A THERMAL TROUGH BACKING INTO THE

SOUTHERN AND CENTRAL PANHANDLE WEDNESDAY WILL KEEP MOST SPOTS

NORTH AND WEST HERE, WHILE THE NORTHERN PANHANDLE IS MAINLY

SOUTHERLY WITH WINDS BLOWING AWAY FROM THE RIDGE CENTER OVER THE

EASTERN GULF. 



 WITH SATURATED GROUND FROM LAST NIGHT'S FRONT EXITING THE

SOUTHERN PANHANDLE INTO BC, EXPECTED LIGHT WINDS UNDERNEATH THE

SURFACE RIDGE, AS WELL AS A STABILIZING ATMOSPHERE WITH WARM AIR

ADVECTION IN THE MID LEVELS AND THUS CLEARING SKIES, WEDNESDAY

MORNING, AND YES, EVEN THURSDAY MORNING ARE GOOD SET-UPS FOR FOG

OVER THE INNER CHANNELS. KEPT MUCH OF THE IDEAS OF LAST SHIFT,

ALTHOUGH REMOVED YAKUTAT AS GUIDANCE NOT HINTING AT IT HERE. IN

COORDINATION WITH SHORT-TERM, DID INTRODUCE SOME FOG FORMATION IN

THE OFFSHORE WATERS UNDERNEATH THE RIDGE. IT REMAINS TO BE SEEN

IF/WHEN THIS FORMS WHETHER THIS FOG EVENTUALLY REACHES ELFIN

COVE, SITKA, AND CRAIG. AT THIS POINT, DO BRING THE MARINE

STRATUS ONSHROE LATE WEDNESDAY NIGHT INTO THURSDAY, BUT CHOSE NOT

TO CARRY FOG AS THIS FOG LAYER HAS YET TO DEVELOP. 



 THE AFOREMENTIONED ATMOSPHERIC STABILITY WILL CLEAR THE SKIES

ACROSS MUCH OF THE PANHANDLE WEDNESDAY AND THURSDAY, ESPECIALLY

IN THE SOUTH. DID USE GEM AS A CLOUD COVER GUIDE, BUT CONFIDENCE

IN ANY OF THE MODELS IS NOT GREAT. KEPT NORTHERN PANHANDLE AT

PARTLY CLOUDY GIVEN THE RISK OF CLOUDS INVADING OVER THE TOP OF

THE RIDGE. WITH REDUCED CLOUD COVER, DID LOWER TEMPERATURES TO

FREEZING IN THE MENDENHALL VALLEY THURSDAY MORNING AND TO UPPER

30S DOWNTOWN JUNEAU/DOUGLAS. OTHER SPOTS WILL FLIRT/REACH THE

FREEZING POINT: YAKUTAT, GUSTAVUS, HAINES CUSTOMS, HOONAH IN

PARTICULAR. AS THE DATE GETS CLOSER AND WEDNESDAY MORNING LOWS

COME IN, THE HOPE IS TO GET A BETTER HANDLE ON THIS.  



 ALL SIGNS POINT TO ANOTHER WET WEEKEND. RAIN IN YAKUTAT IS

DEFINITE FOR FRIDAY, AND CONFIDENCE MOUNTING FOR RAIN INTO THE

PANHANDLE FOR SATURDAY, BUT KEPT LIKELY WORDING FOR NOW. LIKE THE

LAST FRONT, THIS WILL LIKELY HAVE A TROPICAL CONNECTION, SO QPF

WILL NEED TO BE WATCHED. GIVEN THE DRY MID WEEK, RIVERS SHOULD

HAVE PLENTY OF TIME TO LOWER BEFORE THIS NEXT ROUND.  



 KEPT GFS/ECMWF/WPC INFLUENCED FORECAST. CONFIDENCE IN OVERALL

PATTERN GOOD. LESS SO ON THE DETAILS.   



.AJK WATCHES/WARNINGS/ADVISORIES...

PUBLIC...DENSE FOG ADVISORY UNTIL 9 AM AKDT THIS MORNING FOR AKZ026-027.

MARINE...SMALL CRAFT ADVISORY FOR PKZ012. 

         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ052. 



&&



$$



ABJ/JWA








FXAK67 PAJK 171407

AFDAJK



SOUTHEAST ALASKA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE JUNEAU AK

607 AM AKDT THU OCT 17 2013



.SHORT TERM...UPPER LEVEL RIDGE IS WEAKENING EARLY THIS MORNING

AS A SHORTWAVE SKIRTS ITS EASTERN PERIPHERY, RIDING UP OVER THE

TOP AND ONCE IT DOES WILL FLATTEN IT AND CAUSE SKIES TO BE A

LITTLE DIRTIER AS WE SAY IN ATMOSPHERIC SCIENCE. DESPITE THIS, WE

STILL ARE FORECASTING PARTLY CLOUDY SKIES THIS AFTERNOON OVER THE

NORTH...EMPHASIZING MORE CLOUDS THAN SUN, BUT THINK FOLKS WILL

SEE THEIR SHADOWS AT SOME TIME TODAY...ALTHOUGH THE SHADOWS MAY

BE LESS EASILY SEEN LATE THIS AFTERNOON AS HIGH CLOUDS THICKEN.

THE PANHANDLE WILL SEE INCREASING CLOUDS TONIGHT FOR SURE AS

SOUTHWEST FLOW DIRECTS MORE SOLID MID-LEVEL MOISTURE OVER THE

AREA. YAKUTAT WILL LIKELY SEE VERY LITTLE CLEARING TODAY AND EVEN

AS THE MID- LEVEL STRATUS BREAKS UP THIS MORNING, CLOUDS WILL

THICKEN ALOFT AND BECOME LADEN WITH RAIN LATE TONIGHT AS RAIN

DEVELOPS FROM THE WEST. THE FAR NORTHERN PANHANDLE FROM PELICAN

EAST TO GUSTAVUS AND NORTH TO HAINES WILL SEE A CHANCE OF RAIN

LATE. A FRONT MOVING INTO THE NORTHEAST GULF TONIGHT WILL BE

RESPONSIBLE FOR THE PRECIPITATION AND STRENGTHEN NORTHEAST WINDS

OVER YAKUTAT BAY AS WELL AS CROSS SOUND LATE. THE NORTHERN GULF

WATERS WILL SEE GALE FORCE WINDS LATE TONIGHT WITH THE FRONT. IN

ADDITION, LEE-SIDE TROUGHING IN THE YUKON WILL KEEP WINDS UP TO

20 KT TONIGHT FOR NORTHERN LYNN CANAL AND SKAGWAY. NAM IS

DISAGREEING WITH THE ECMWF ON THIS ONE. EVEN THOUGH THE NAM

SEEMED TO BE HANDLING THE LIGHT NORTHERLIES THIS MORNING OVER THE

CANAL...HAVE BEEN FAVORING THE ECMWF WHILE LOOKING AT THIS TIME

PERIOD THE LAST FEW DAYS, AND AM STICKING TO MY FORECAST OF A

SLOW RISE IN WINDS FOR THURSDAY AFTERNOON INTO THURSDAY NIGHT.

SOUTH OF LYNN CANAL, WINDS WILL MAINLY BE LIGHT NORTHWEST TODAY

WITH SOME LIGHT SOUTHERLIES BUILDING TOMORROW OVER THE CENTRAL

PANHANDLE AS THE SURFACE RIDGE EXITS TO THE SOUTHEAST. 



FOG IS ANOTHER ISSUE. THE CLEAR SKIES AND LIGHT WINDS OVER THE

CENTRAL PANHANDLE HAS ALLOWED DENSE FOG TO DEVELOP AROUND WRANGELL

AND PETERSBURG, AND THUS A DENSE FOG ADVISORY HAS BEEN ISSUED

UNTIL 10 AM. GIVEN LOWER SUN ANGLES...FOG WILL LIKELY TAKE ITS

TIME TO DISSIPATE ALTOGETHER, BUT THE HOPE IS BY NOON. FOG WILL

LIKELY REFORM AGAIN TONIGHT FOR AREAS SOUTH OF JUNEAU, BUT WITH

SKIES BECOMING MOSTLY CLOUDY LATE, THE FOG WILL LIKELY BE LESS OF

AN ISSUE, AND DOUBT ANY WILL BE DENSE. THE SPORT MODIS-VIIRS NIGHT

MICROPHYSICS IMAGE HAS PROVIDED EXCELLENT IMAGES DEPICTING THE

LOCATION OF FOG...IN LOCAL DRAINAGE AREAS LIKE THE CHILKAT VALLEY

TO THE BACKSIDE OF DOUGLAS AND SOUTH TO EASTERN FREDERICK SOUND.



NO MAJOR CHANGES TO TEMPERATURE, OTHER THAN COOLING THE SOUTHERN

INNER CHANNELS FOR TONIGHT TO NEAR 40...FEEL THAT THEY WILL HAVE

ANOTHER MAINLY CLEAR TO PARTLY CLOUDY NIGHT. ELSEWHERE,

TEMPERATURES LOOKED ON TRACK FOR THE NEXT 24 HOURS.



OVERALL LIKED THE NAM FOR THE FIRST 12 HOURS BUT USING MORE ECMWF

FOR TONIGHT. CONFIDENCE IN FORECAST AVERAGE.





.LONG TERM...TWO FRONTAL BOUNDARIES WILL MOVE EAST ACROSS THE

GULF TO THE PANHANDLE THROUGH THIS WEEKEND. THE FIRST WILL MOVE

ONSHORE THE PANHANDLE FRI MORNING, AND THE SECOND ON SATURDAY. 

THE LARGEST CHANGES TO THE LONG RANGE FORECAST PACKAGE ARE DUE 

TO RAISING THE POPS AND QPF FOR THE FIRST FRONT.



AT 12Z FRI A 500H TROUGH ALOFT WILL EXTEND FROM OVER KODIAK

AND TO THE ESE MOST OF THE WAY ACROSS THE GULF.  THIS TROUGH 

WILL BE ASSOCIATED WITH AN OCCLUDING FRONTAL SYSTEM THAT 

SHOULD MOVE EAST ACROSS THE GULF AND REACH THE PANHANDLE FRI

MORNING. THE SOURCE REGION FOR THIS SYSTEM IS A SPLIT IN ZONAL

FLOW OVER THE CHAIN, WITH A NORTHERN BRANCH THAT FLOWS NNE THROUGH

THE TROUGH ALOFT.



THE FIRST OCCLUDED FRONT WILL BE ABOUT 200 NM OFFSHORE OF A 

YAKUTAT-SITKA LINE AT 12Z FRI.  THE LANDFALL OF THIS SYSTEM 

DURING DAYTIME FRIDAY HAS BEEN GIVEN RAISED POP AND QPF VALUES.

YAKUTAT IS FORECAST TO HAVE RAIN HEAVY AT TIMES FRI.  POPS WERE 

RAISED 20 TO 30 PERCENT FOR MOST OF THE PANHANDLE EXCEPT 

ZONES 28 AND 29.



THE CONFIDENCE IS LIMITED BY A LARGE-SCALE LOW IN THE NW PACIFIC

THAT HAS A STRONG TROPICAL ORIGIN. A LOOP OF THE GOES IR ON A 

PACIFIC MERCATOR PROJECTION HAS BEEN USEFUL FOR SEEING THE RAPID 

TRANSITION FROM A TYPHOON THAT WAS ABOUT 600 NM S OF JAPAN ON TUE, 

TO A NEW LOW THAT WAS ROUGHLY 600 NM SW OF SHEMYA ABOUT 06Z THU. 

THE MODEL CONSENSUS IS GOOD FOR THE LOW TO DEEPEN TO ABOUT 962 MB

IN THE VICINITY OF SHEMYA AT 00Z FRI. THIS LARGE AND DEEP SYSTEM

WILL DEVELOP THE SECOND OCCLUSION, AND THIS FRONTAL BOUNDARY WILL

PASS THE YAKUTAT TO SITKA LINE ABOUT 21Z SAT.



.AJK WATCHES/WARNINGS/ADVISORIES...

PUBLIC...DENSE FOG ADVISORY UNTIL 10 AM AKDT THIS MORNING FOR AKZ026.

MARINE...GALE WARNING FOR PKZ052. 

         SMALL CRAFT ADVISORY FOR PKZ043-051. 



&&



$$



JWA/JBT










FXAK67 PAJK 221314

AFDAJK



SOUTHEAST ALASKA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE JUNEAU AK

514 AM AKDT TUE APR 22 2014



.SHORT TERM...RATHER QUIET ACROSS THE AREA THIS MORNING WITH

SOME AREAS OF HIGH CLOUDS AND PATCHY FOG. THE HIGH CLOUDS OVER

THE NORTHERN PANHANDLE ARE FROM A WEAKENING UPPER TROUGH THAT IS

DROPPING SW OUT OF THE YUKON WHILE THE HIGH CLOUDS OVER THE SOUTH

ARE FROM THE LEADING EDGE OF ANOTHER WEAK UPPER TROUGH THAT WILL

BE LIFTING NW OVER THE PANHANDLE THROUGH TONIGHT. IN ADDITION

NIGHTTIME MICROPHYSICS IMAGES FROM MODIS AND VIIRS REVEAL SOME

PATCHY FOG AND LOW CLOUDS AROUND PRINCE OF WALES ISLAND AND

YAKUTAT. THE FOG AROUND PRINCE OF WALES HAS PROVED TO BE DENSE IN

SOME PLACES AS HYDABURG AND KLAWOCK BOTH HAVE HAD VISIBILITIES OF

A QUARTER MILE AT TIMES THIS MORNING. AS SUCH A DENSE FOG

ADVISORY WAS ISSUED FOR HYDABURG AND KLAWOCK AREAS UNTIL 8 AM

WHEN THE FOG IS EXPECTED TO BURN OFF AS THE SUN RISES. 



THE WEATHER TODAY IS EXPECTED TO BE RATHER NICE FOR MOST OF THE

PANHANDLE. MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH

HIGH INTO THE UPPER 40 TO MID 50S FOR MOST PLACES. WINDS ARE ALSO

EXPECTED TO BE LIGHT THOUGH SOME HIGHER WINDS FROM SEA BREEZES

COULD CROP UP THIS AFTERNOON. THE EXCEPTION IS THE SOUTHERN

PANHANDLE WHERE CLOUDS WILL BE INCREASING TODAY AS THE UPPER

TROUGH OVER BRITISH COLUMBIA STARTS TO MOVE IN.



INTO TONIGHT, CLOUDS WILL INCREASE FOR MOST AREAS AS THE UPPER

TROUGH MOVES NW. SHOWERS WILL ALSO START TO BECOME A THREAT FROM

SOUTH TO NORTH TONIGHT. THE SOUTHERN PANHANDLE WILL HAVE THE BEST

CHANCE OF RAIN LATE THIS AFTERNOON AND EVENING WHILE THE NORTH

WILL SEE THE BEST CHANCE THIS EVENING INTO THE LATE NIGHT. IT WILL

NOT QUITE GET TO YAKUTAT BY LATE TONIGHT. RAINFALL WILL BE RATHER

LIGHT WITH HIGHER AMOUNTS OBSERVED THE CLOSER TO THE COAST

MOUNTAINS YOU ARE DUE TO DOWNSLOPING FLOW. THE SOUTHERN PANHANDLE

MAY START CLEARING AND DRYING OUT LATER TONIGHT WHICH COULD LEAD

TO FOG FORMATION AGAIN THERE. AS SUCH I HAVE INSERTED SOME PATCHY

FOG INTO THE FORECAST FOR LATE TONIGHT FOR THE SOUTH.



SHORT RANGE MODELS WERE IN GOOD AGREEMENT THOUGH THERE WERE SOME

DETAIL DIFFERENCES FOR THE INCOMING TROUGH. PRIMARILY WENT WITH

THE NAM AND SOME ECMWF FOR OVERALL UPDATES AS BOTH LOOKED TO HAVE

MORE OF THE CURRENT DETAILS. OVERALL CHANGES WERE MINOR.



&&



.LONG TERM...MODEL GUIDANCE CONTINUES TO COME INTO BETTER

AGREEMENT WITH THE TRACK AND AMPLITUDE OF A COMPACT MIDLEVEL

SHORTWAVE TROUGH MOVING N ACROSS THE PANHANDLE WED MORNING

THROUGH THU AFTERNOON. MODEST ASCENT/MOISTENING ASSOCIATED WITH

THIS FEATURE COMBINED WITH A COLD MIDLEVEL AIRMASS /-30 TO -35C

AT H5/ WILL SUPPORT SCATTERED RAIN SHOWERS WED AFTERNOON OVER THE

NRN HALF OF THE CWA...THEN BECOMING ISOLATED ON THU. MEANWHILE...A

DRY MIDLEVEL AIRMASS IS FORECAST TO SPREAD ACROSS THE SRN HALF OF

THE CWA THU MORNING AND AFTERNOON AS THE PREVIOUSLY MENTIONED

DISTURBANCE EXITS N. THE COMBINATION OF DECREASING CLOUDS AND

INCREASING 850 MB TEMPERATURES PROMPTED A BUMP UP IN THU DAYTIME

HIGHS FOR SRN AREAS...WITH VALUES EXPECTED TO REACH THE MID TO

UPPER 50S.



THE NEXT IN A SERIES OF SMALL-SCALE UPPER WAVES IS THEN FORECAST

TO MOVE N INTO THE CWA FRI AND SAT. CONFIDENCE IS NOT HIGH IN THE

EXACT EVOLUTION OF THIS NEXT FEATURE...BUT AN INCREASE IN CLOUDS

AND LOW PRECIPITATION CHANCES APPEARS PLAUSIBLE. NUDGED FRI HIGH

TEMPERATURES DOWN FROM THOSE EXPECTED ON THU DUE TO THE INCREASE

IN CLOUD COVER. IN FACT...LITTLE AIRMASS CHANGE IS FORECAST FRI

THROUGH TUE. THUS...HIGHS IN THE LOW TO MID 50S AND LOWS IN THE

30S ARE MAINTAINED DURING THE REMAINDER OF THE LONG-TERM.

ENSEMBLE AND DETERMINISTIC MODEL GUIDANCE SHOWS A SYNOPTIC-SCALE

TROUGH WILL BECOME POSITIONED OVER THE GULF AND NERN PAC BY THE

START OF THE NEXT WORK WEEK. THOUGH PREDICTABILITY IS FAIRLY HIGH

WITH THIS LARGE TROUGH...CONFIDENCE IS LOW WITH REGARD TO EMBEDDED

IMPULSES PINWHEELING NWD FROM THE TROUGH INTO SE AK. FOR THIS

REASON...WPC GUIDANCE BASED ON THE ENSEMBLE ECMWF WAS PRIMARILY

USED FOR THE LATER HALF OF THE EXTENDED.



.AJK WATCHES/WARNINGS/ADVISORIES...

PUBLIC...DENSE FOG ADVISORY UNTIL 8 AM AKDT THIS MORNING FOR AKZ027.

MARINE...SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041>043-051. 



&&



$$



EAL/GARNER