Gale Warning 219, NWS Juneau, AK

556 
FZAK67 PAJK 222315
OFFAJK

OFFSHORE WATERS FORECAST
NATIONAL WEATHER SERVICE JUNEAU AK
400 PM AKDT THU SEP 22 2016 

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.

PKZ398-231400-
400 PM AKDT THU SEP 22 2016 
.SYNOPSIS FOR THE EASTERN GULF OF ALASKA...
A FRONT OVER THE PANHANDLE WILL MOVE INTO CANADA THU NIGHT.
BEHIND THE FRONT SW WINDS TO 20 KT WILL BLOW ACROSS THE GULF AND
INTO THE OUTER COAST THROUGH FRI NIGHT. 

$$

PKZ310-231400-
GULF OF ALASKA NORTH OF 55 DEGREES NORTH AND EAST OF 144 DEGREES
WEST-
400 PM AKDT THU SEP 22 2016 

.TONIGHT...W WIND 20 KT. SEAS 13 FT SUBSIDING TO 10 FT LATE. S
SWELL IN THE EVENING. SLIGHT CHANCE OF THUNDERSTORMS. 
.FRI...SW WIND 20 KT. SEAS 10 FT. S SWELL. SLIGHT CHANCE OF
THUNDERSTORMS. 
.FRI NIGHT...S WIND 20 KT. SEAS 9 FT. SW SWELL. SLIGHT CHANCE OF
THUNDERSTORMS. 
.SAT...S WIND 15 KT. SEAS 8 FT. SW SWELL. SLIGHT CHANCE OF
THUNDERSTORMS. 
.SAT NIGHT...WINDS LIGHT INCREASING TO W 15 KT LATE. SEAS 7 FT.
SW SWELL. SLIGHT CHANCE OF THUNDERSTORMS. 
.SUN...S WIND 15 KT. SEAS 6 FT. 
.MON...NW WIND 20 KT. SEAS 7 FT. 
.TUE...W WIND 15 KT. SEAS 8 FT. 

$$

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
325 PM AKDT WED SEP 21 2016

.SHORT TERM...Nice day across the area with mostly to partly
cloudy skies. A persistent area of low clouds and fog plagued the
southern inner channels today with the light winds and moist
boundary layer. Fog stuck around until around noon in many areas
and a little fog still lingers around Wrangell with low clouds
over Clarence Strait this afternoon.

Main focus for the next 24 hours is the storm force front that
will be making its way east across the gulf. Several minor waves
have formed will be riding north along the front and helping it
move east. The strongest of these waves will be heading toward
Cape Suckling late tonight and will be responsible for the storm
force winds in the NE gulf. This initial wave will briefly stall
the front over the northern gulf coast tonight but once it passes
the westerly flow behind the front and subsequent shortwaves will
rapidly push the front through the panhandle on Thu.

Winds will be the main issue with the pre-frontal low level jet
strength reaching 70 to 80 kt over the gulf and 45 to 60 kt over
the panhandle. Many areas of the gulf will see storm force or at
least gale force winds and seas up to 30 feet as a result before
frontal passage. Yakutat itself will likely see gusts up to 50
mph, but barrier jet effects may cause these winds to end up
higher or lower depending on how well it keeps the higher winds
channeled offshore. Highest winds expected late tonight into early
tomorrow for the gulf and northern gulf coast. Inner channel areas
will see a combination of gale force winds for marine areas and
strong wind gust to 45 or 50 mph for land areas depending on how
exposed to southerly winds an area is. Highest winds here are
expected Thu morning into Thu afternoon. The only areas that may
escape the higher winds will be Skagway, Haines and Hyder as the
first two will be somewhat sheltered from this flow direction and
the latter is a little too far east and rather sheltered to get
into the higher winds yet.

Rain is the other issue. The stalling of the front over the
northern gulf tonight will result in a longer period of moderate
rain. Expect around 3 to 4 inches to fall in Yakutat through
tomorrow afternoon. Farther east, the front will start moving to
fast for any moderate to heavy rain to stick around over an area
for an extended period of time. Expected rainfall totals will
likely be around 1 inch with some areas seeing as much as 2 inches
due to local effects.

There is also some decent cool air coming in behind the front.
Model lifted indexes are reaching -2 or less in the gulf Thu
afternoon with some cape values reaching 300 or more joules. Best
upper level dynamics are immediately post-front so kept the
slight chance of thunder going in that area Thu. Farther out in
the gulf 500 mb temps are dropping to -25 C or less across a wide
area reinforcing the idea of instability across the gulf Thu
afternoon. As a result, slight chances of thunder remain for most
of the gulf Thu.

Short range models had a decent handle of the strong system today.
Some timing issues still to deal with as the GFS was slightly
faster bringing the front across the panhandle then most other
models. Mostly kept any changes relegated to local details and
used some hi-res NAM to help up wind speeds across the land areas
of the inner channels.

.LONG TERM...The strong front discussed in the short term portion
of the AFD is forecast to dissipate quickly over the panhandle
during Thursday night as a zone of upper divergence exits away
from the region. Gales may linger over Clarence Strait briefly, as
well as small craft SLYS for Lynn Canal...but winds for both
areas are expected to weaken during the night as the surface
pressure gradient slackens. Otherwise, cold midlevel temperatures
will spread east across the gulf and panhandle, aiding in steep
lapse rates and sufficient CAPE for a slight chance of
thunderstorms over the outer waters and immediate gulf coast.
Thunderstorm development will be most probable in the vicinity of
upper disturbances, which are hard to predict this far out...thus
kept thunder mentioned for the entire gulf through the weekend.

Meanwhile, model guidance shows a low-level frontal zone trailing
west across the NRN Pacific, which evolves into a series of
frontal waves during the weekend over the NERN PAC/SERN gulf. The
strongest wave is forecast to develop Sunday night into Monday as
upper divergence strengthens over the front. Model spread is
currently very large with the subsequent evolution of the low, but
this systems has the potential to produce hazardous weather
conditions across the region.

&&

.AJK Watches/Warnings/Advisories...
PUBLIC...STRONG WIND from Thursday morning through Thursday afternoon for
     AKZ024-026-027.
     STRONG WIND from late tonight through Thursday afternoon for
     AKZ025.
     STRONG WIND from 1 AM AKDT Thursday through Thursday afternoon
     for AKZ022.
     STRONG WIND from late tonight through Thursday afternoon for
     AKZ020-021-023.
     STRONG WIND from Thursday morning through Thursday afternoon for
     AKZ028.
     STRONG WIND from 1 AM AKDT Thursday through Thursday morning for
     AKZ017.
MARINE...Storm Warning for PKZ022-042-043-051-052.
     Gale Warning for PKZ013-021-031>036-041-053.
     Small Craft Advisory for PKZ011-012.
&&

EAL/Garner

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