High Wind Watch 4, NWS Juneau, AK

624 
WWAK77 PAJK 090702
NPWAJK

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE JUNEAU AK
1102 PM AKDT THU SEP 8 2016

AKZ023-091900-
/O.CON.PAJK.HW.A.0004.160909T2100Z-160910T0200Z/
CAPE DECISION TO SALISBURY SOUND COASTAL AREA-
INCLUDING THE CITIES OF...SITKA...PORT ALEXANDER
1102 PM AKDT THU SEP 8 2016

...HIGH WIND WATCH REMAINS IN EFFECT FRIDAY AFTERNOON...

* LOCATION...OUTER COAST OF BARANOF ISLAND.

* WINDS...SOUTH WINDS 20 TO 30 MPH BECOMING WEST 30 TO 40 MPH 
  WITH GUSTS TO 60 MPH POSSIBLE. 

* TIMING...WIND SHIFT AROUND 4 PM THEN THE STRONGEST WESTERLIES
  BETWEEN 4 TO 6 PM. 

* IMPACTS...HIGH WINDS MAY UPROOT TREES AND PRODUCE FALLING 
  BRANCHES CAUSING POWER OUTAGES AND DAMAGE TO STRUCTURES. 
  MOORED VESSELS AND AIRCRAFT TIED DOWN OUTDOORS WILL BE AT 
  RISK. LOOSE OBJECTS MAY BE BLOWN AROUND. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WATCH MEANS THERE IS THE POTENTIAL FOR A HAZARDOUS
HIGH WIND EVENT. SUSTAINED WINDS OF AT LEAST 40 MPH... OR GUSTS
OF 58 MPH OR STRONGER MAY OCCUR.  CONTINUE TO MONITOR THE LATEST
FORECASTS.

&&

$$

006 
WWAK77 PAJK 091253
NPWAJK

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE JUNEAU AK
453 AM AKDT FRI SEP 9 2016

AKZ023-092100-
/O.UPG.PAJK.HW.A.0004.160909T2100Z-160910T0200Z/
/O.NEW.PAJK.HW.W.0006.160909T2300Z-160910T0300Z/
CAPE DECISION TO SALISBURY SOUND COASTAL AREA-
INCLUDING THE CITIES OF...SITKA...PORT ALEXANDER
453 AM AKDT FRI SEP 9 2016

...HIGH WIND WARNING IN EFFECT FROM 3 PM THIS AFTERNOON TO 7 PM
AKDT THIS EVENING...

THE NATIONAL WEATHER SERVICE IN JUNEAU HAS ISSUED A HIGH WIND
WARNING...WHICH IS IN EFFECT FROM 3 PM THIS AFTERNOON TO 7 PM
AKDT THIS EVENING. THE HIGH WIND WATCH IS NO LONGER IN EFFECT. 

* LOCATION...OUTER COAST OF BARANOF ISLAND.

* WINDS...SOUTH WINDS 20 TO 30 MPH BECOMING WEST 35 TO 45 MPH
  WITH GUSTS TO 60 MPH.

* TIMING...WIND SHIFT AROUND 3 PM THEN THE STRONGEST WESTERLIES 
  BETWEEN 4 TO 6 PM. 

* IMPACTS...HIGH WINDS MAY UPROOT TREES AND PRODUCE FALLING 
  BRANCHES CAUSING POWER OUTAGES AND DAMAGE TO STRUCTURES. 
  MOORED VESSELS AND AIRCRAFT TIED DOWN OUTDOORS WILL BE AT 
  RISK. LOOSE OBJECTS MAY BE BLOWN AROUND. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A HIGH WIND WARNING MEANS A HAZARDOUS HIGH WIND EVENT IS EXPECTED
OR OCCURRING. SUSTAINED WIND SPEEDS OF AT LEAST 40 MPH OR GUSTS
OF 58 MPH OR MORE CAN LEAD TO PROPERTY DAMAGE.

THIS STATEMENT WILL BE UPDATED AT 1 PM AKDT FRIDAY OR SOONER IF
CONDITIONS WARRANT.

&&

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
527 AM AKDT THU SEP 8 2016

.SHORT TERM...First significant storm system of the fall season
to begin impacting the eastern Gulf of Alaska and the panhandle
tonight...

For today, multiple weak shortwaves crossing the panhandle will
generate isolated to scattered showers. Winds over the area will
remain less than 15 kt into this afternoon.

Then, we turn our attention to a rapidly deepening low pressure
system which will move into the eastern gulf by late tonight.
Impressive upper level dynamics associated with this system
including the remnants of Hurricane Lester will make for
deteriorating conditions over the gulf and panhandle tonight. Pre-
frontal southeasterly winds of 40-45 kt will lift north through
the eastern gulf. Post-frontal winds will shift southwesterly and
increase to gale force. Seas will also be quickly building
through the night. A strong low level jet will bring gale force
winds to portions of the inner channels. Strong wind gusts of
40-45 mph will develop late tonight along the outer coastal areas
and into Kuiu and Kupreanof Islands. Several factors are coming
together for this to be quite a rainmaker as well. Subtropical
moisture entrained within the system, significant warm air
advection, and strong low level south-southwest flow enhancing
orographic effects will lead to rain becoming heavy at times late
tonight across a large portion of the area. Precipitable water
values climb to between 1 to 1.5 inches which is 2 to 3 standard
deviations above normal for this time of year. Rainfall rates by
late tonight will likely be around 0.25 inches/hour.

Please see the special weather statement and hydrologic outlook
for more information on this hazardous weather system.

Used the 06z NAM/00z GFS for updates to the previous forecast.

.LONG TERM...The low pressure system described in the short term
continues to track towards the eastern gulf. Still seeing
variations in the exact track of the low with each new model run.
00z runs had the low center further east and tracking north of
cross sound by Friday, then redeveloping over the Yukon Friday
evening. 06z runs now have the low tracking straight into Cross
Sound then tracking along a Cross Sound to Juneau corridor Friday
evening. Each solution produces gales force winds over the gulf
and inner channels, potential storm force winds in westerlies
south of the low center, and strong winds with gusts of 40 mph
and higher over portions of the panhandle. The differences is in
the details on where exactly these winds will occur. Used a broad
brush approach due to the uncertainty, continuing to increase
winds for any location now indicated by the latest MOS guidance.
As airmass transitions from stable to unstable with cold air mass
aloft moving in expect more wide spread regions of higher winds.

Precip will switch to showers as colder airmass aloft moves in.
Chance of thunder storms over the gulf and coastal panhandle
remain but will need to nail down timing. Some model 3 hour qpf
values for Friday over 1 inch with latest model track putting
heaviest amounts over the central panhandle. By Saturday showers
will begin to diminish as the low moves inland and ridging builds
over the gulf. Winds diminish quickly through the day with a
general drying trend for late Saturday Sunday.

The period of lighter winds, clearer skies and dry weather will
be short lives as next wave advances into the northern AK gulf
late Sunday into Monday. Along with the increasing winds, but not
quite as strong as the current system, will see set up for
atmospheric river. Precipitable water values once again at 2 to 3
standard deviations above normal for Monday into Tuesday.

Used a blend of 00z GFS/GEM initially but then began to
utilize more of the 06z GFS/NAM for last minute wind adjustments.
If the newest model runs do not change the central panhandle will
bear the brunt of the storm Friday afternoon and evening.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...STRONG WIND late tonight for AKZ022-026-028.
     STRONG WIND late tonight for AKZ023-027.
MARINE...Gale Warning for PKZ022-033-036-041>043-051-052.
     Small Craft Advisory for PKZ021-031-032-034-035.
&&

TPS/PRB

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