High Wind Warning 12, NWS Juneau, AK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
404 PM AKDT Mon Oct 17 2022

.SHORT TERM...Through Wednesday night/...A very strong low is
still on track to move through north the gulf and it is still
expected to bring strong winds and high seas. The EURO ensemble
probability maps are putting >90% chance of wind gusts >50 kts in
the eastern gulf Wednesday morning.

The low is still on track to make landfall just west of Yakutat
Wednesday afternoon. As it does, a couple rounds of strong winds
will track over SE AK. The first round will be on the leading edge
of the associated front and is expected to be weaker of the two,
with speeds upwards of 40 kts (near 45 mph) with gusts near 50 kts
(near 55 mph). Along with the winds, Tuesday morning will bring
the longest lasting precipitation for the inner channels before a
brief intermission of lighter precipitation. This front will
track along the panhandle Tuesday night. Inner channel winds will
pick up to around 25 to 30 kts.

Wednesday is when the low will move over the northern gulf and
make landfall. As it does, eastern gulf winds will be from the
south shifting to southwest (counter-clockwise around the low)
and gain speed to around 45 to 50 kts in the open ocean, 40 to 45
kts along the coast. Gusts in the open ocean will be near 55 to 60
kts, 45 to 55 along the coast. Inner channel wind speeds on
Wednesday are expected to be around 25 to 35 knots and they should
decrease Wednesday night, as the low tracks inland and weakens.
During this time, the heaviest precipitation for both the
northeast gulf coast and inner channels will fall. Residual
onshore flow caused by the inland tracking low will lift
orographically along the northeast gulf coast and southward along Baranof
Island. Total accumulations range between 2-4 inches through
Wednesday night and 1-2 inches expected elsewhere.

Strong, gusty winds over land areas are possible with this system
as well. While gusts to near 40 mph are a safe bet for most
places, Yakutat, Skagway, and Sitka are the areas we’ve tried to
narrow down to where gusts to near 60 mph are possible. And
Yakutat should see a shift in the winds - from a easterly
component to southwest - as the low makes landfall and moves
north.

.LONG TERM.../Thursday through Monday/...Rainy conditions persist
as the low pressure dissolves into a short wave and the overall
flow becomes onshore. As the short wave passes, ensemble models
have good agreement on a new low developing over the Bering Sea
and moving along the northeast gulf coast. The front associated
with this low moves into the panhandle Thursday through Friday
bringing 1-3 inches of rain in 48 hours. Small craft to possible
gales are expected along the outer coast as the front progresses
with greater winds along the front line. Looking toward the
weekend, cooler temperatures and light, northerly flow from the
building continental ridge look to follow the diminishing low and
frontal feature. Ensemble members are pointing toward a ridge
building in the north central gulf before being replaced by a low
moving in from Bering Strait. Currently, confidence is low on the
weekend system as ensemble members do not have good agreement on
the placement of the low and its interaction with the building
ridge.

&&

.AVIATION...Seeing a window of VFR category conditions across the
central Panhandle at this time with periods of showers bringing
lower visibility and ceilings to PAYA, and IFR slowly lifting for
a brief time across the southern Panhandle over the next 3 hours
as the front moves east. The reprise will be short lived as by
morning lower visibilities/ceilings will be working northward
across the Panhandle as the next storm system (a deepening
hurricane force low over the central Gulf) makes its way northward.
Started bringing winds up at most TAF locations starting tomorrow
morning with stronger winds working in by late afternoon across
the area.

&&

.MARINE...Marine winds and seas will see great impacts from this
incoming storm. Seas are still forecasted to reach 30 to 40 feet
on the eastern side of the low late Tuesday into Wednesday. Wave
heights in the inner channels are also expected to rise due to the
strong winds of 20 to 35 kts beginning Tuesday night and lasting
into Wednesday. Wind speeds should start to increase Tuesday
afternoon with the arrival of the associated front, then as the
low moves closer, wind speeds will be reinforced so a secondary
increase should occur late Tuesday night into Wednesday. After the
low makes landfall and weakens, allowing the pressure gradient
relaxes, then speeds should decrease - this will happen late
Wednesday into Wednesday night from south to north.

&&

.HYDROLOGY...While this system will not be as warm as previous
systems, significant rainfall will occur especially over areas
recently affected by heavy rainfall from atmospheric rivers last
week. A general 2 to 4 inches of rainfall is expected from early
Tuesday morning through Wednesday night across roughly the
northern one third of the panhandle. Rivers and streams are
already running high so with this in mind, thought it prudent to
issue a Flood Watch for the northern portions of the Panhandle
including the Taiya Basin and the Juneau area. At least minor
flooding is possible as heavy rain falls on already saturated
ground.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch from Tuesday afternoon through late Wednesday night
     for AKZ317>320-325.
     High Wind Watch from Tuesday afternoon through Wednesday evening
     for AKZ317-323.
     High Wind Watch from Wednesday morning through late Wednesday
     night for AKZ318.
     Strong Wind Tuesday afternoon for AKZ323.
     Small Craft Advisory from 7 AM to 6 PM AKDT Tuesday for AKZ330.
MARINE...Gale Warning for PKZ022-041>043-051-052.
     Small Craft Advisory for PKZ021-032-033-035-036-053.

&&

SHORT TERM...GJS
LONG TERM....NTC
AVIATION...JG
HYDROLOGY...DEL

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