888
FXAK67 PAJK 161348
AFDAJK
SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
548 AM AKDT WED OCT 16 2013
.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS MOSTLY CLEAR
SKIES OVER THE SOUTHERN HALF OF THE PANHANDLE WITH SOME AREAS OF
FOG OVER POW AND THE CENTRAL INNER CHANNELS. THE NORTHERN HALF
STILL HAVE SOME MID LEVELS CLOUDS WITH SOME PATCHY FOG IN PLACES.
SOME OF THE FOG IS LESS THAN 1 MILES AT TIMES WHICH WILL SLOWLY
DISSIPATE THROUGH THE MORNING HOURS. THE IS ONSHORE MID LEVEL
FLOW OVER THE NORTH CENTRAL AREAS WHICH IS PRODUCING SOME DRIZZLE
WILL VEER TO THE NORTHWEST THROUGH THE LATE MORNING AND ALLOW THE
DRIZZLE TO DIMINISH.
THE WINDS ACROSS MOST OF THE FORECAST AREA ARE ON THE LIGHT SIDE
BUT LYNN CANAL IS STILL BLOWING 20 TO 15 KT FROM THE SOUTH WHILE
THE FAR SOUTHERN AREAS ARE SEEING 15 KT FROM THE NORTHWEST. THESE
WINDS WILL REMAIN PERSISTENT THROUGH TODAY BUT AS THE HIGH
PRESSURE OVER THE EASTERN GULF AND PANHANDLE SLIDES EAST AND
WEAKENS ALL OF THE WINDS WILL DIMINISH EARLY THIS EVENING.
CLOUD COVER WAS VERY TRICK FOR THE NEXT 24HRS. THE SOUTHERN HALF
OF SE AK WILL REMAIN TO SEE MOSTLY SUNNY SKIES WITH DEEP OFF
SHORE FLOW FROM THE NORTHWEST. THE MID LEVEL CLOUDS OVER THE
NORTHERN HALF WILL SLOWLY DECREASE THROUGH THIS AFTERNOON AS THE
FLOW BECOMES MORE NORTHWEST TO BECOME PARTLY CLOUDY. LOW CLOUDS
AND FOG WILL MOVE INTO THE EASTERN GULF THROUGH THIS AFTERNOON AS
THE UPPER HIGH DRIFTS TO THE EAST TO BE OVER THE FORECAST AREA BY
TONIGHT. AS THIS HAPPENS THE LOW CLOUDS FROM THE GULF WILL INVADE
THE INNER CHANNELS. AREAS OF FOG WILL DEVELOP TONIGHT OVER MOST
PLACES WITH LIGHT WINDS AND LARGE BREAKS IN THE CLOUD COVER OR
WITH MOSTLY CLEAR SKIES.
OVERALL THERE WAS MINOR CHANGES TO THE FORECAST AND THERE IS
ABOUT AVERAGE FORECASTER CONFIDENCE THROUGH THE SHORT TERM
PERIOD. USED A BLEND OF THE NAM/EC FOR THE FIRST 24HRS.
.LONG TERM...THE RIDGE THAT HAS MADE ITS HOME OVER THE PANHANDLE
AND THE EASTERN GULF HERE IN MID-WEEK WILL SLOWLY RECEDE TO THE
EAST AND SOUTH THROUGH FRIDAY. THIS WILL TRANSITION THE
PREVAILING WEATHER CONCERNS FROM SKY COVER, FOG, AND NAMING WIND
DIRECTIONS IN SUCH LIGHT FLOW AT THE SURFACE TO ONE OF RAIN AND
BOOSTING WINDS IN RESPONSE TO AN APPROACHING FRONT IN THE GULF ON
FRIDAY, AND A SECOND FRONT ON ITS HEALS FOR SATURDAY.
TO START, VERY LITTLE CHANGES IN SKY COVER. STILL HAVE THE
MARINE STRATUS ON THE WEST COAST WITH SOME MOVEMENT INTO ICY
STRAIT THURSDAY MORNING...WHILE CLOUDS GENERALLY RECEDE BACK TO
THE SHORE IN THE AFTERNOON. AREAS OF FOG WILL DISSIPATE THURSDAY
MORNING OVER MOST PANHANDLE LOCATIONS SOMETIME THURSDAY MORNING,
BUT GIVEN THE LOWERING SUN ANGLES THIS TIME OF YEAR, WOULD NOT BE
SHOCKED IF SOME OF IT STUCK AROUND INTO THE AFTERNOON. OVERALL,
SKIES WILL BE PARTLY CLOUDY IN THE NORTHERN INTERIOR TO SUNNY IN
THE SOUTH. TEMPERATURES ALSO LOOKED REASONABLE.
MADE A FEW SUBSTANTIVE CHANGES TO THE POP FIELD, IN THAT MOVED
JUNEAU INTO THE LIKELY CATEGORY FRIDAY AFTERNOON BUT THE FORECAST
LOOKS ON TRACK FOR SURE. YAKUTAT WILL SEE THE RAIN DEVELOP FROM
THE WEST ON THURSDAY NIGHT. BY SATURDAY THE FRONT SHOULD ENSURE
RAIN REGION-WIDE, AND SINCE IT GENERALLY STALLS OR SLOWS DOWN
INTO THE WEEKEND, RAIN WILL BE LIKELY THROUGH THE REST OF THE
WEEKEND. BEYOND THAT SOUTHWEST FLOW ALOFT OR POSSIBLY SOME
INDICATIONS OF ANOTHER RIDGE BUILDING, AT LEAST LIMIT RAIN TO A
CHANCE FOR THE NEXT WEEK.
THE MAIN CHANGES TO THIS FORECAST WERE RESERVED FOR WINDS. KEPT
WINDS LARGELY LIGHT AND NORTHERLY/WESTERLY FOR THURSDAY AS THE
SURFACE RIDGE AXIS STILL LIES TO THE WEST. STREAMLINES IN THE
LOWER LEVELS SUGGEST A LIGHT GEOSTROPHIC FLOW FROM ICY STRAIT
SOUTH. JUNEAU AND LYNN CANAL WERE THE EXCEPTION AS SOUTH WINDS
ARE MORE IN LINE WITH THE GRADIENT FLOW, AND THEY SHOULD
STRENGTHEN IN THE CANAL AS THE PRESSURE GRADIENT TIGHTENS THROUGH
THURSDAY AND REMAINS SUCH THAT 20 KTS WILL BE THE GENERAL RULE
FROM THURSDAY AFTERNOON INTO FRIDAY WHERE WINDS WILL LIKELY REACH
SMALL CRAFT. WINDS GRADUALLY TRANSITION IN THE CENTRAL PANHANDLE
TO SOUTHERLY/EASTERLY ON THURSDAY NIGHT AND FINALLY SPREAD THE
DIRECTIONAL FLIP TO THE SOUTHERN PANHANDLE ON FRIDAY AS THE RIDGE
EXITS TO THE SOUTHEAST AND THE GRADIENT RESPONDS TO THE
APPROACHING FRONT IN THE GULF.
WINDS WILL RISE TO SMALL CRAFT FOR NORTHERN LYNN FRIDAY INTO
SATURDAY AND IN CROSS SOUND FOR SATURDAY AS THE SECOND FRONT
REACHES THE PANHANDLE. CONFIDENCE LOW BUT GIVEN SOME RECENT
FRONTAL PASSAGES, DID PUT IN DIRECTIONAL CHANGE TO WEST IN CROSS
SOUND FOR SATURDAY AFTERNOON WITH ANOTHER PRONOUNCED SURGE OF
SMALL CRAFT POST-FRONTAL. CHOSE NOT TO COVER IT IN THE ZONE TEXT,
BUT IT WILL BE IN THE POINT-AND-CLICK. IT SHOULD ALSO BE NOTED
THAT ECMWF OPERATIONAL MODEL, WHICH SEEMS TO REPRESENTED THE LYNN
CANAL GRADIENT BEST RECENTLY IS ADVERTISING A GRADIENT OF OVER
3 MB BETWEEN JUNEAU AND SKAGWAY SATURDAY EVENING WHICH WOULD
SUGGEST MINIMUM GALE IS POSSIBLE. BUT WE HAVE TIME TO FINE-TUNE
THIS IN SUCCESSIVE SHIFTS. IN ANY CASE, THE TREND UPWARDS HAS
BEEN SET FOR THE INSIDE CHANNELS THROUGH THIS WEEKEND.
NUDGED PRESSURE FIELD TO EC AND NAM THURSDAY INTO THURSDAY NIGHT
AND THEN TO ECMWF FROM FRIDAY INTO SATURDAY NIGHT TO TACKLE
WINDS. CONFIDENCE IN FORECAST GOOD INTO THE EARLY WEEKEND, BUT
FALLING INTO NEXT WEEK.
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ052.
&&
$$
ABJ/JWA