Gale Warning 17, NWS Juneau, AK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
410 PM AKST SAT JAN 23 2016

.SHORT TERM...THE LATEST SATELLITE IMAGERY SHOWS A WEAK WEATHER
FRONT OVER THE CENTRAL GULF. THERE ARE SOME LINGERING SHOWERS OVER
THE NORTHERN HALF OF THE FORECASTER AREA WITH SOME BROKEN SKIES
OVER THE SOUTHERN AREAS. WINDS FOR THE MOST PART ARE ON THE
LIGHTER SIDE BUT THERE IS SOME INCREASE SOUTH WINDS IN LYNN CANAL
TO 25 KT AND SOME GUSTY WINDS NEAR SKAGWAY.

THE SHOWERS OVER THE INNER CHANNELS WILL SLOWLY DISSIPATE SOME
THIS EVENING AS A UPPER RIDGE MOVES OVER THE AREA AHEAD OF A THE
UPPER TROF ASSOCIATED WITH THE WEAK FRONT OVER THE GULF. THE FRONT
OVER THE GULF IS PRODUCING SOME MAX SMALL CRAFT WINDS AT THIS TIME
AND THESE WILL SPREAD EASTWARD THROUGH TONIGHT AND INCREASE SOME
TO MIN GALES AS IT BEGINS TO INTERACT WITH THE LAND ALONG THE
COASTAL AREAS. RAIN WILL SPREAD OVER THE COASTAL AREAS SLOWLY LATE
TONIGHT AND THEN SPREAD OVER THE NORTHERN TWO THIRDS OVER THE
FORECAST AREA EARLY SUNDAY MORNING. THE SOUTHERN AREAS WILL SEE A
DELAY IN THE ONSET OF THE RAIN WITH STRONG ANTI-CYCLONIC FLOW FROM
THE WEAK UPPER RIDGE. ONCE THE RIDGE SLIDES TO THE EAST RAIN WILL
DEVELOP AND INCREASE THROUGH THE AFTERNOON. FREEZING LEVELS WILL
REMAIN ABOVE 1500 FEET SO ALL PLACES NEAR SEA LEVEL WILL SEE RAIN
BUT THE KLONDIKE HIGHWAY MAY SEE A FEW INCHES THROUGH SUNDAY
AFTERNOON.

WIND WISE...ALONG WITH THE MIN GALES OVER THE EASTERN GULF SEAS
WILL INCREASE TO BE NEAR 15 FT. THE SOUTH WINDS OVER THE INNER
CHANNELS EARLY THIS EVENING WILL SLOWLY RELAX AS THE PRESSURE
GRADIENT BECOMES MORE E/W. SO WITH THAT SAID THE SMALL CRAFT WINDS
NEAR LYNN CANAL WILL BECOME LESS THAN 15 KT LATE TONIGHT AND
PERSIST INTO SUNDAY. THE E/W WINDS WILL INCREASE OVERNIGHT AS THE
FRONT APPROACHES NEAR ICY STRAIT AND CROSS SOUND TO BE 20 TO 25 KT.
THE WINDS WILL SLOWLY DECREASE THROUGH THE DAY ON SUNDAY AS THE
PRESSURE GRADIENT RELAXES. THE REST OF THE INNER CHANNELS WILL
SEE SOUTHEAST WINDS FROM 15 TO 20 KT. OVER LAND THE WINDS WILL BE
ON THE GUSTY SIDE ALONG THE COASTAL AREAS FROM THE ESE. THE INNER
CHANNELS WILL SEE SOME INCREASED WIND SPEEDS SUNDAY MORNING BUT
THEY WILL NOT LAST LONG AS THE FRONT FALLS APART THROUGH THE DAY.

OVERALL THERE IS ABOUT AVERAGE FORECASTER CONFIDENCE AND USED THE
12Z GFS22 FOR ANY UPDATES DONE IN THE SHORT TERM PERIOD.

.LONG TERM...A SERIES OF WEATHER FRONTS WILL AFFECT SE AK ALL NEXT
WEEK. A STRONG 200 MPH JETSTREAM OVER THE EASTERN PACIFIC TODAY
WILL HELP CARVE OUT AN UPPER LEVEL TROUGH UNDER A COLD STATIONARY UPPER
LOW VICINITY OF EASTERN ALEUTIANS. AS THE ALEUTIAN LOW DIGS
IN...AN UPPER LEVEL RIDGE BUILDS FARTHER EAST OVER WESTERN NORTH
AMERICA. THE RESULT IS A MILD AND WET SW FLOW ALOFT AIMED AT SE AK
THROUGHOUT THE LONG RANGE PERIOD.

SAT MORNING GFS EC AND CANADIAN MODELS GENERALLY AGREE ON THE
FORECAST PATTERN. FELT THE GFS AND CANADIAN MAY HAVE BEEN SOMEWHAT
BETTER INITIALIZED THIS MORNING PARTICULARLY WITH THE SURFACE
WEATHER FRONTS OVER THE NORTH PACIFIC. DEVELOPING CYCLONE AROUND
40N 170W SAT AFTERNOON IS IN GOOD POSITION TO DEVELOP AND
STRENGTHEN AS IT APPROACHES SE AK MON. AFTER COORDINATING WITH WFO
ANCHORAGE WE EXPECT THIS GALE TO MOVE TO THE NE GULF BY MON NIGHT
WITH STORM FORCE GUSTS OVER THE NORTHERN COASTAL WATERS. WE
FOLLOWED THE CANADIAN MODEL PRESSURE AND WIND GUIDANCE FOR SAKE OF
CONSISTENCY. AS THIS GALE MOVES PAST SE AK MON NIGHT SURFACE HIGH
PRESSURE WILL BUILD IN STRONGLY OVER THE INNER CHANNELS TUES.
MODEL GUIDANCE SUGGESTS STRONG WIND PATTERN BUILDING S TO N TUES.
THIS BEARS WATCHING FOR POSSIBLE HIGH WIND HEADLINES TUES.

YET ANOTHER SURFACE LOW IS SHOWN HEADING TO SE AK THUR. MODEL
STATISTICAL GUIDANCE INDICATE POSSIBLE HEAVY PRECIP RATES WITH
THESE FRONTS TOO. SNOW LEVEL SHOULD BE ABOVE SEA LEVEL ALL WEEK
AND PROBABLY FLUCTUATE BETWEEN 1000 AND 4000 FT MSL ACROSS
PANHANDLE. BEST CHANCE FOR ACCUMULATING SNOW WILL BE THE NORTHERN
INNER CHANNELS AND HIGHWAY PASSES. FORECASTER CONFIDENCE IS
CONSIDERED AVERAGE THROUGH THE LONG RANGE PERIOD.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ042-043-051-052.
     SMALL CRAFT ADVISORY FOR PKZ012-013-022-033-041.
     SMALL CRAFT ADVISORY DUE TO SEAS FOR PKZ053.
&&

ABJ/TA

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