Area Forecast Discussion
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FXAK67 PAJK 012347
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
347 PM AKDT WED APR 1 2015

.SHORT TERM...STUBBORN SHOWER ACTIVITY OVER MOSTLY THE NORTHERN
PORTIONS OF THE PANHANDLE IS RELATED TO RESIDUAL
INSTABILITY/MOISTURE ASSOCIATED WITH LAST NIGHT`S WAVE WHICH WAS
PASSING THROUGH THIS MORNING. RIDGING BEHIND THE WEAK WAVE AND
AHEAD OF THE NEW LOW ALREADY MOVING IN FROM THE WEST SHOULD
SUPPRESS THE REMAINING SHOWER ACTIVITY OVER THE NEXT FEW HOURS. IN
FACT SOME AREAS WILL LIKELY SEE PARTIAL CLEARING PRIOR TO ONSET OF UPPER
CLOUD LATER THIS EVENING. NORTHERN LYNN STILL HAS SOUTH WINDS AT
20 KT BUT DIE OFF SHORTLY ALONG WITH WINDS AT SKAGWAY.

NEW LOW APPEARS LIKELY TO CAUSE MARGINAL OFFSHORE GALES TONIGHT
AND EARLY TOMORROW FOR THE ADJACENT ZONES AND THE BARRIER JET
REGION OVER THE NORTHWEST...BEFORE WIND SPEEDS DECREASE AS LOW STALLS
AND BEGINS TO WEAKEN TOMORROW. THIS IS ADVERTISED IN THE 12Z MODEL
UPDATES. ALSO SCA- LEVEL WINDS EXPECTED OVER THE SOUTH AND CENTRAL
PANHANDLE INNER CHANNELS...PARTICULARLY THE SOUTHERNMOST ZONES AS
WELL AS THOSE WITH FAVORABLE ORIENTATIONS TO THE EAST- WEST
PRESSURE GRADIENT...FOR A PERIOD LATE TONIGHT AND EARLY TOMORROW.
ONLY TWEAKING OF THE WINDS IN THE CHANNELS AND OFFSHORE PER THE
MODEL UPDATES WAS NECESSARY. OTHERWISE UTILIZED INHERITED PRESSURE
GRIDS AND UPDATED THE THERMODYNAMIC FIELDS WITH EC/NAM DATA
TONIGHT AND TOMORROW. ANTICIPATED QPF VALUES ARE GREATEST IN THE
SOUTHERN PANHANDLE WHERE PERHAPS 3/4 OF AN INCH WILL FALL IN
SPOTS TONIGHT/TOMORROW...PER PREVIOUS SHIFT THESE VALUES ARE ABOUT
HALF OF WHAT THE NAM WAS PREDICTING YESTERDAY. THAT TREND WILL NOT
LIKELY CONTINUE THIS EVENING. PRECIP WILL DIMINISH FROM NORTH TO
SOUTH LATE TOMORROW AND MAY BECOME PREDOMINANTLY SHOWERS AS THE
LOW WEAKENS AFTER 21Z. ALSO LATE TONIGHT SOME THREAT OF LOCAL
JUNEAU WIND GUSTS INCREASING TO 25 KT BUT NOT REALLY EVEN A
MARGINAL TAKU SITUATION AS STABLE LAYER IS LOW AND WEAK. ARW MODEL SHOWS
GUSTS TO ABOUT 25 OR 30 KTS AS A PERIOD OF RELATIVELY SHALLOW
CROSS- BARRIER FLOW IS PROGGED LATE TONIGHT. ALSO WINDS COULD GET
UP INTO THE 30-35KT GUST RANGE LATE TONIGHT IN THE SOUTHERNMOST
ZONES BUT WITH THE LOW STALLING AND WEAKENING DO NOT FEEL STRONG
WIND WORDING IS WARRANTED AT THIS POINT. NO PRECIP TYPE ISSUES ARE
PRESENT TONIGHT OR TOMORROW OUTSIDE OF WHITE PASS AND HAINES
CUSTOMS. THERE IS SOME THREAT OF CONVECTION OVER THE SOUTHERN
MARINE ZONES FOR LATE TOMORROW BUT NOT ENOUGH CONFIDENCE AT THIS
POINT TO PUT IT INTO THE FORECAST...THREAT APPEARS GREATER FOR THU
NIGHT AND FRI AT THIS POINT. TWEAKED TOMORROWS MAXT FIELDS UP
ABOUT 1-2F FOR MOST LOCATIONS PER MOS GUIDANCE.

.LONG TERM...THE LOW WILL SLOW MOVE SOUTHEAST TO BE ABOUT 300 NM
WEST OF WASHINGTON STATE BY SATURDAY AFTERNOON. AS THE LOW MOVES
SOUTH EXPECT TO SEE SHOWERS GENERALLY TAPER OFF FROM THE NORTH.
THE UPPER LEVEL FLOW PATTERN IS DIGGING THE UPPER TROUGH ALONG
THE WEST COAST OF NORTH AMERICA TO STEER THE WEATHER SYSTEMS FROM
COLD BAY SOUTHWARD TO MOVE ONSHORE IN THE CALIFORNIA. ALOFT THE
ZONAL FLOW ACROSS THE NORTH PACIFIC FROM ASIA TO THE EASTERN
ALEUTIANS.

THERE IS THROUGH IN THE MUCH WEAKER NORTHERN STREAM THAT WILL BE
MOVE EAST FROM PRINCE WILLIAM SOUND TO THE YAKUTAT AREA OVER THE
WEEKEND. LOTS OF COLDS AIR ALOFT WITH A VORTICITY LOBE DROPPING
THROUGH THE BASE OF THE TROUGH ACROSS NORTHERN GULF. SHOULD SEE
SOME SHOWERS DEVELOPING OF THE NORTHEAST GULF COAST AND INTO THE
NORTHERN PANHANDLE LATE SATURDAY AND SUNDAY AS THE TROUGH
TRANSITIONS ACROSS THE NORTHERN PANHANDLE.

LONGER RANGE MODELS AND THE ENSEMBLE MEANS ARE BRINGING A FAIRLY
STRONG DEVELOPING SYSTEM ACROSS THE BERING SEA EARLY NEXT WEEK THAT
SHOULD BE DEPOSITED INTO THE WESTERN GULF OF ALASKA BY MID WEEK.
THIS SYSTEM WILL LEAD TO A RIDGE BEING REFORMED ALONG THE BRITISH
COLUMBIA COAST AND SOUTHEAST ALASKA PANHANDLE. THIS SHOULD BRING
SOME WARMER TEMPERATURES NORTHWARD TO SOUTHERN SOUTHEAST ALASKA
AROUND MIDWEEK AHEAD OF THE STRONG SYSTEM TO IMPACT THE AREA
AROUND WEDNESDAY.


&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...NONE.
MARINE...GALE WARNING FOR PKZ041>043-051-052.
         SMALL CRAFT ADVISORY FOR PKZ021-022-033>036-053.

&&

$$

WESLEY/BEZENEK

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








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