Area Forecast Discussion
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FXAK67 PAJK 290142 CCA
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
351 PM AKDT FRI AUG 28 2015

.SHORT TERM...RATHER WET, GRAY DAY ACROSS THE PANHANDLE TODAY AS A
990 MB LOW NEAR 56N 140W SLOWLY SLIDES TO THE SE. ITS ASSOCIATED
FRONT HAS STALLED OVER THE SOUTHERN PANHANDLE AND CONTINUES TO
PUMP A GOOD DEAL OF RAIN INTO THAT AREA. KETCHIKAN AND ANNETTE
HAVE BEEN SEEING AROUND A QUARTER INCH OF RAIN EVERY HOUR SINCE
AROUND 6 AM WITH HIGHER RAINFALL RATES SEEN IN THE HIGHER TERRAIN.
PW RETRIEVALS ALONG THIS FRONT ARE ONLY REACHING 1.1 INCHES WHICH
IS AROUND 130 PERCENT OF NORMAL. WINDS HAVE ALSO BEEN GUSTY ALONG
THIS FRONT AS WELL. A STRONG WIND HEADLINE REMAINS UP FOR ZONE 28
AS KETCHIKAN AND ANNETTE HAVE BEEN GUSTING TO NEAR 40 MPH ALL DAY.
A GALE WARNING ALSO REMAINS UP FOR CLARENCE STRAIT THROUGH THIS
EVENING.

ELSEWHERE RAINFALL RATES LIGHTEN UP CONSIDERABLY ONCE YOU GET TO
THE OUTER COAST OR NORTHERN PANHANDLE AND YAKUTAT HAS ENDED UP
WITH A DRY DAY AND MOSTLY TO PARTLY CLOUDY SKIES. AIDING THAT
DRYING TREND IS NORTHERLY OUTFLOW THAT IS CURRENTLY BLOWING
THROUGH THE VARIOUS INTERIOR PASSES OF THE NORTHERN PANHANDLE. A
WEAK BUT COOL SURFACE HIGH HAS INFILTRATED THE SOUTHERN YUKON AND
INCREASED NORTHERLY PRESSURE GRADIENTS ALONG THE ST. ELIAS RANGE.
NORTHERN LYNN CANAL IS CURRENTLY BLOWING GALE FORCE WITH CROSS
SOUND SEEING SMALL CRAFT WINDS AND THE PASSES EAST OF YAKUTAT ARE
ALSO SEEING GUSTY WINDS.

INTO TONIGHT AND TOMORROW THE LOW IN THE GULF AND THE FRONT WILL
EXPERIENCE A GRADUAL WEAKENING TREND. THOUGH WITH THE FRONT
STALLED OVER THE SOUTHERN PANHANDLE THE RAIN AND WIND THERE WILL
NOT QUIT ANYTIME SOON JUST GRADUALLY DIMINISH. FARTHER NORTH, A
FRONTAL RAIN BAND IS HEADING NORTHWEST ALONG THE PANHANDLE THIS
EVENING AND WILL BEING MORE RAIN TO MOST AREAS. HOWEVER IT WILL
BE WEAKENING AS IT GOES AND WILL ONLY PRODUCE LIGHT RAIN BY THE
TIME IT GETS TO THE NORTHERN PANHANDLE. YAKUTAT WILL ALSO GET IN
ON THIS BAND BUT WITH IT FIGHTING THE OUTFLOW NOT MUCH RAIN IS
EXPECTED OUT OF IT ONCE IT GETS THAT FAR WEST AND NORTH. ALSO OF
CONSIDERATION IS THE COLD TROUGH OVER THE GULF LOW. THIS HAS BEEN
SPARKING OFF SOME THUNDERSTORMS TO THE WEST OF THE LOW CENTER IN
THE GULF ALL DAY. THE THREAT OF THUNDERSTORMS CONTINUES INTO
TOMORROW IN THE GULF AND MAY GET ONSHORE AROUND BARANOF ISLAND
TOMORROW AFTERNOON AS THE MAIN PART OF THE UPPER TROUGH STARTS TO
MOVE EAST. AS SUCH HAVE INCLUDED A SLIGHT CHANCE OF THUNDERSTORMS
FOR THESE AREAS.

AS FOR THE OUTFLOW WINDS OVER THE NORTHERN PANHANDLE, THE INTERIOR
ALASKA HIGH WILL BE GRADUALLY WEAKENING OVER THE NEXT 24 HOURS SO
WINDS SHOULD START TO CALM DOWN TONIGHT. PRESSURE GRADIENTS
CONTINUE TO WEAKEN TOMORROW SO WINDS SHOULD REMAIN BELOW SMALL
CRAFT CRITERIA TOMORROW.

SHORT RANGE MODELS WERE IN GOOD AGREEMENT FOR THE NEXT 24 HOURS.
USED HI-RES NAM FOR MODEL GUIDANCE TODAY WHICH HELPED IN FINE
TUNING THE FRONTAL WINDS IN THE SOUTHERN PANHANDLE AND THE OUTFLOW
WINDS IN THE NORTHERN PANHANDLE.

.LONG TERM...THE UPPER LEVEL LONG-WAVE TROUGH ALONG THE WEST COAST
OF NORTH AMERICA TO ABOUT NORTHERN CALIFORNIA IS ALTERING TO A LOWER
AMPLITUDE TROUGH THROUGH THE WEEKEND. A SECOND SHORT WAVE MOVES INTO
THE WESTERN GULF SATURDAY AFTERNOON WITH A 140 KT JET MAXIMA. IT
WILL HELP MOVE THE SYSTEM QUICKLY EAST ACROSS THE GULF AND INTO THE
SOUTHERN PANHANDLE AND BRITISH COLUMBIA COAST. I SUSPECT THE BEST
RAINFALL TOTALS AND WIND FEATURES WILL IMPACT BRITISH COLUMBIA MORE
SO THAN THE SOUTHERN PANHANDLE. RAINFALL ACROSS THE SOUTHERN
PANHANDLE LOOKS TO BE 1 TO 2 INCHES WHICH WILL RAISE STREAMS BACK UP
BUT SHOULD NOT RESULT IN ANY FLOODING ISSUES. HOWEVER, A SLIGHTLY
MORE NORTHERLY TRACK OF THE SYSTEM COULD BRING THE HEAVIER RAINS
NORTH OF THE DIXON ENTRANCE REGION.

A THIRD SHORT WAVE HEADED SOUTHEAST WILL STEER THE UPPER LOW THAT
HAD BEEN OVER THE ALASKAN INTERIOR INTO THE NORTHEAST GULF OF ALASKA
FOR MONDAY. THE UPPER LEVEL RIDGE OVER THE WEST COAST OF ALASKA WILL
THEN START BUILDING EAST ACROSS THE GULF THROUGH MID WEEK. THE
DIMINISHING CHANCE OF PRECIPITATION MONDAY TO WEDNESDAY FROM THE
NORTH TO SOUTH PATTERN CONTINUES TO LOOK ON TRACK.

DID WORK ON SOME MORE MODIFICATION OF THE TEMPERATURES WITH THE
DRIER/LESS CLOUDY WEATHER...BUT OVERALL ONLY MINOR CHANGES TO MOST
MID RANGE ITEMS.

USED A BLEND OF THE ECMWF AND GFS THROUGH THE WEEKEND AND THEN
STARTED TO TRANSITION OVER THE HPC GUIDANCE AND HAVE GOOD TO
AVERAGE CONFIDENCE IN THE FORECAST.


&&

.HYDROLOGY...NONE OF THE RAIN OVER THE SOUTHERN PANHANDLE IS
CREATING SIGNIFICANT HYDRO CONCERNS AT THE MOMENT. STANEY CREEK NEAR
KLAWOCK ROSE 5 FEET THIS MORNING, BUT WITH ALL THE HEAVIER RAIN NOW
TO ITS EAST, THE CREEK IS CRESTING AROUND 2 FEET BELOW BANKFULL. IT
IS EXPECTED TO CONTINUE TO DROP THROUGH TONIGHT. AS FOR THE
WATERWAYS NEAR KETCHIKAN, THEY HAVE ONLY RISEN A FOOT OR SO. THIS IS
MOSTLY BECAUSE THE QUARTER OF AN INCH AN HOUR RAINFALL IS NOT EVEN
CLOSE TO THE 1 YEAR RECURRENCE INTERVAL FOR HOURLY RAINFALL FOR THE
AREA. AS SUCH, WHILE CREEK AND STREAM LEVELS WILL RISE, NO FLOODING
ISSUES ARE NOT EXPECTED AT THIS TIME AND THE GRADUALLY DIMINISHING
RAIN RATES WILL ONLY HELP THE SITUATION.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...STRONG WIND UNTIL 10 PM AKDT THIS EVENING FOR AKZ028.
MARINE...GALE WARNING FOR PKZ012-036.
         SMALL CRAFT ADVISORY FOR PKZ013-022-043-051.
         SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ041-042-052.

&&

$$

EAL/BEZENEK

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