Gale Warning 178, NWS Juneau, AK

756 
FZAK67 PAJK 032317
OFFAJK

Offshore Waters Forecast
National Weather Service Juneau AK
317 PM AKDT Fri Aug 3 2018

Offshore waters forecast for Gulf of Alaska east of 144W

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent the average of the highest
one-third of the combined windwave and swell height.

PKZ398-041730-
317 PM AKDT Fri Aug 3 2018
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A strong low over the northwest gulf will move southeast to be
near position 50 North 140 West, south of the Gulf of Alaska, by 
Saturday afternoon. The low will continue to drift slowly south 
through Sunday. 

$$

PKZ310-041730-
Gulf of Alaska North of 55 Degrees North and East of 144 Degrees
West-
317 PM AKDT Fri Aug 3 2018

.TONIGHT...SE wind 20 kt. Seas 8 ft. SW swell. 
.SAT...Winds light increasing to E 20 kt in the afternoon.
Seas 8 ft. W swell. 
.SAT NIGHT...E wind 20 kt. Seas 8 ft. SW swell. 
.SUN...E wind 15 kt in the morning becoming variable less than
15 kt. Seas 8 ft. SE swell. 
.SUN NIGHT...Wind variable less than 15 kt. Seas 6 ft. SE
swell. 
.MON...SW wind 15 kt. Seas 6 ft. 
.TUE...S wind 15 kt. Seas 6 ft or less. 
.WED...S wind 15 kt. Seas 6 ft or less. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
215 PM AKDT Thu Aug 2 2018

.SHORT TERM...Pattern shift well underway this afternoon. Low
clouds and areas of very light rain and drizzle have developed
across much of the area as of this writing. Winds remain generally
light with the exception of Lynn Canal/Taiya Inlet where some
S'ly winds to 25kt are persisting.

Strong jet max seen on WV imagery early this afternoon will
continue to emerge into the western Gulf this evening. Associated
mid level low will drop into the NW Gulf by early Friday. Strong
diffluence and mid level DPVA will spawn a robust surface low for
this time of year over the northern Gulf by Friday morning. Most
guidance takes the low down into the mid 980mb range before slowly
weakening as it drifts slowly SE through Saturday night. A strong
front will approach the inside waters by Saturday afternoon and
drift into the the Panhandle during the evening before stalling.
Low level wind response to the deepening low will also be quite
impressive for early August. NAM and GFS both indicate a low level
jet of 55 to 65 kt along the eastern Gulf coast by Friday
afternoon. Think gale force conditions a good bet over the eastern
Gulf and likely into S. Chatham, Sumner, and Clarence Strait as
well. East/west channels are the most likely to be affected over
the inside waters given the orientation of the low level jet and
the surface gradient. Winds to 30kt are likely in these areas much
of Friday afternoon into Friday night. The exception will be Lynn
Canal where in spite of the strong low level jet, think stability
and a parallel pressure gradient may actually keep winds light
over the northern part of the channel.

Layer precipitable water analysis this afternoon shows a very long
fetch of strong moisture transport extending from the western
Pacific into the western Gulf. This moisture will get caught up in
the developing circulation in the Gulf and be wrapped up towards
the Panhandle. Deep layer moist S'ly flow will be favorable for
periods of heavy rain at times late Friday into Friday night. 1 to
2 inches of storm total rainfall is likely especially over
southern areas by late Saturday. All in all, it will feel much
more likely autumn than the glorious summer weather we have been
enjoying.

Closed mid and upper level trough will continue to dig into
eastern NPAC by Saturday night with mid level ridging building in
from the west over the top of the closed low. This should allow
the stream of moisture to be cut off and shift back towards the
west and south. Thus the precipitation should diminish quickly
late Saturday from SE to NW and the winds should subside as well
giving those with outdoor plans at least a glimmer of hope for the
end of Saturday.

.LONG TERM.../Saturday through Thursday as of 10 PM Wednesday/...
Much of the panhandle will experience a wet start to the weekend,
while Sunday may turn out to be rather pleasant across the
southern half of SE Alaska. Upper trough over the Gulf will persist
Saturday with a deep layer cyclone spinning over the NPAC.Expected
to break off into a closed low early Sunday and dive south.
Weak upper level ridging builds in over the southern Gulf with a
strong jet over mainland AK. With this, a more zonal flow pattern
is expected to set up early next week with a series of midlevel
shortwaves streaming across the northern Gulf.

Minor adjustments were made to the previous forecast with
preference towards the GFS solution. Continued to increase wind
speeds along the occluded front which looks to hang around the
outer coast with 25-35 kt winds for a day and half, collapsing
late Saturday. Kept with SCA winds into Southern Chatham and
Clarence Strait into Saturday afternoon. Biggest change was made
to PoPs and temperatures Sunday thru Monday across the southern
Panhandle, where likely to see more dry conditions with
temperatures rebounding back to lower 70s and lighter winds.
Nudged to WPC guidance after Monday next week. Forecaster
confidence is average.

&&

.HYDROLOGY...Most rivers and streams remain well below bankfull as
of early this afternoon. Widespread moderate precipitation is
expected with some of the rain becoming heavy at times Friday
evening and overnight. The Chilkat and Taiya Rivers remain high in
response to the recent warm weather. Deep southerly flow will be
favorable for solid rainfall rates even into the northern channels
for a time Friday and Friday night. Thus will likely see the both
rivers approach bankfull conditions on Saturday. Elsewhere, there
are no immediate hydro concerns due to the recent dry weather. In
fact, the rain will be a welcome relief to areas of the southern
Panhandle that remain in abnormally dry or moderate drought
conditions.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind Friday afternoon for AKZ027-028.
     Strong Wind Friday afternoon for AKZ025.
MARINE...Gale Warning for PKZ022-033-035-036-041>043-051-052.
     Small Craft Advisory for PKZ012-013-021-031-032-034.

&&

DEL/DDH

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