Area Forecast Discussion
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FXAK67 PAJK 090131
AFDAJK

SOUTHEAST ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JUNEAU AK
431 PM AKST MON FEB 8 2016

.SHORT TERM...SW FLOW ALOFT WITH A BRANCH OF THE UPPER JET AIMED AT
CAPE SPENCER WHILE THERE IS A STRONG WEST COAST RIDGE INLAND.
SATELLITE IMAGERY REVEALS QUITE A STREAM OF MOISTURE ORIGINATING
FROM THE SUBTROPICS WHICH CAUSED SOME PRECIPITATION RECORDS TO BE
BROKEN TODAY FOR THE SOUTHERN PANHANDLE. THE FORECAST CHALLENGE ON
THIS SHIFT HAS BEEN THE TRACK AND STRENGTH OF A GALE FORCE LOW THAT
DEVELOPED TO THE SOUTH AND IS MOVING UP THE COAST. AT ONE POINT
THIS LOW WAS BELOW 1000 MB. WE ALSO HAD ONE CLUSTER OF LIGHTNING IN
THE OFFSHORE WATERS EARLIER BUT THIS HAS SUBSIDED.

08/12 NAM WAS THE CLOSEST ON SURFACE PRESSURE INITIALIZATION. USED
THAT ONE FOR THESE FORECASTS INCLUDING DRYING TUESDAY AFTERNOON AS
THE MOISTURE BAND DISSIPATES. WIND FORECASTS WERE QUITE DIFFICULT
WITH THE LOW CENTER AND THE NAW INSISTS THAT A LOW WILL DEVELOP IN
THE EASTERN YUKON BY 12Z TUE FOR SOME REAL WIND SHIFTS. THE OLD LOW
CENTER WILL DIE OUT NEAR YAKUTAT. THE JET IS CAUSING CHANGES TO
HAPPEN REALLY FAST AND TRIED TO CAPTURE THIS.

.AVIATION...THIS HAS BEEN A TOUGH SET OF TAFS. LOW LEVEL MOISTURE
HAS CAUSED IFR CONDS IN AND OUT PLUS THE POTENTIAL FOR LLWS
TONIGHT. EXPECT VFR CONDS TOMORROW AFTERNOON.

&&

.MARINE...SEAS OUTSIDE ARE BIG AND FORECASTED GALES AROUND THE LOW
BUT CONDS ARE CHANGING FAST AND HARD TO EXPRESS THE WIND SHIFTS
AROUND THE COMPASS. GALES WILL SUBSIDE LATER TONIGHT BUT LOOK FOR
THE NEXT SYSTEM TO BE MOVING UP FROM THE SOUTH LATER ON TUE.

&&

.HYDROLOGY...SO MUCH RAIN IN THE SOUTH PART AROUND 4 INCHES IN
SOME SPOTS IN THE LAST 36 HOURS. GOOD THING THE STREAMS AND
RIVERS WERE LOW ALTHOUGH THE SOILS WERE SATURATED ACCORDING TO
SOME SPOTTERS. NO IMPACTS. TIDES IN ESTUARIES ARE HIGH AT MAX
WATER.

&&

.LONG TERM...THE GULF WILL REMAIN ACTIVE THROUGH THE LONG TERM
PERIOD WITH A SERIES OF LOW PRESSURE SYSTEMS MOVING INTO THE GULF
OF ALASKA WITH WEATHER FRONTS DRIFTING OVER SEAK. A LONG WAVE
TROUGH WILL REMAIN OVER THE GULF WITH ANOTHER UPPER LOW MOVING
INTO THE GULF FROM THE WEST OVER THE WEEKEND. THERE ARE SOME
DIFFERENCES IN THE DETAILS BUT THERE IS GOOD MODEL AND ENSEMBLE
AGREEMENT WITH THIS PATTERN. THE UPPER TROF WILL KEEP MILD TEMPS
OVER THE FORECAST AREA WITH A SW FETCH AND DEEP ONSHORE FLOW.
THERE MAY BE TIMES THAT THE HIGHWAYS MAY SEE SNOW SNOW BUT FOR THE
MOST PART ALL PRECIPITATION WILL REMAIN IN THE LIQUID FORM. WIND
WISE THERE WILL BE SOME PERIODS OF STRONG WINDS AS WEATHER FRONTS
MOVES THROUGH THE AREA.

WHERE CHANGES WERE MADE USED A BLEND OF THE 18Z NAM AND 12Z EC
THROUGH DAY 4 THEN USED THE NEW WPC FORECAST.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...WINTER WEATHER ADVISORY UNTIL 5 AM AKST TUESDAY FOR AKZ018.
MARINE...GALE WARNING FOR PKZ036-041>043-051.
     SMALL CRAFT ADVISORY FOR PKZ011>013-021-022-031>035-052-053.
&&

$$

JC/ABJ

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