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FXAK67 PAJK 181447
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
647 AM AKDT Tue Mar 18 2025

.SHORT TERM...
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Heading into this morning we have some scattered snow showers in the
northern panhandle from the surface trough that moved over the
panhandle overnight. A ridge that moved over the area behind the
trough has brought some gusty southerly winds to Skagway and Lynn
Canal, which are expected to dissipate before the next low in the
Gulf approaches and encourages a switch to northerly winds in the
early evening hours.

As we get to this afternoon, the gale force front approaching from
the south will begin to bring up the wind speeds and precipitation
in the southern panhandle before moving up through the northern
panhandle this evening. We will see the highest precipitation rates
in the southern panhandle, where it will fall as rain due to the
higher snow levels, wet bulb temperatures and after analyzing the
850-1000 mb partial thicknesses. Annette Island, POW and Ketchikan
will see up to 1.5 inches of precipitation during the next 24
hours, while the central and northern panhandle will only see up
to 1 inch. Sitka, Gustavus and Skagway will see less total QPF in
this time, with an expected 0.1 to 0.3 inches in the next 24
hours. The northern half of the panhandle will begin to switch to
a rain and snow mix by tonight, with the exception of the Haines
Highway and Klondike Highway still expecting snow. By early
Wednesday morning the Haines Highway is expected to see
accumulations of around 3 inches of snow, with the heaviest
amounts in the morning hours for a storm snow accumulation total
of up to 7 inches as the system continues to move through the
panhandle. There is a winter storm watch in affect for the Haines
area for this snow threat through Wednesday afternoon. By
Wednesday afternoon, across other areas in the northern
panhandle, will have switched over to a rain as the warm front
brings up warmer air to the panhandle.

The other major concern for tonight is the strong winds (>40mph)
in the southern half of the panhandle with the oncoming front,
with gale force winds expected offshore and into the channels by
tonight. The winds will not be as high for the land areas of POW,
Ketchikan, and Annette Island except for in high elevations such
as Yellow Hill. A low level jet is expected over Dixon Entrance
and the southern panhandle with 925 mb winds between 55 and 65 kts
as the front moves in, however it will not likely impact any
areas near sea level due to the stable layer between 2000 ft and
the surface preventing momentum transfer to the surface. The
surface trough and frontal pass will still bring some higher winds
to the southern panhandle, with up to 50 kt gusts for Hydaburg,
Craig, and Klawock.

.LONG TERM.../ Wednesday to Saturday /
The very active weather pattern continues as front after front
advances into the panhandle, and while breaks may be possible
between frontal bands, they will be short-lived.

A negatively tilted shortwave trough moving through the area will
be responsible for the latest round of weather, as its
corresponding low moves northward into the east central gulf. As
the low moves north, it will bring with it a trailing front and
gale force winds for the maritime areas. Over land, the strongest
winds will be across the southern panhandle, though many areas
will see gusty conditions. Through Wednesday, an initial burst of
snow with the front will give over to rain or to a rain snow mix
across much of the area as warmer air moves in behind the system,
and expect only minor snow accumulations as a result. The
exception is the Chilkat Valley, where a mixture of cold air
lingering and favorable frontogenesis from the negatively tilted
trough will lead to more substantial accumulating snow. A Winter
Storm Watch has been issued, and amounts of between 4 to 7 inches
of snow are possible, with the greatest amounts along the Haines
Highway at elevations. Precipitation will switch over to rain or a
rain snow mix through Wednesday afternoon as the southerly surge
of warm air advection arrives, though temperatures will rapidly
begin cooling off afterwards and winds will flip back to the north
in Lynn Canal on Thursday.

Late Wednesday into early Thursday will see another impulse along
the front move into the southern panhandle. In its wake, a brief
lull in the precipitation is expected for some locations, though
this will be swiftly brought to an end as another trough enters
the gulf through Thursday. Alongside the trough, another front
will enter the panhandle late Thursday to Friday. This front will
also have brisk winds for the coastal communities and likely gale
force for the marines on the outside especially south of Cross
sound. Another system will arrive Sunday, also bringing elevated
winds.
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&&

.AVIATION...
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Predominate MVFR or worse flight conditions expected across the
panhandle today as on-shore showery regime turns into a front
pushing into the area through Tuesday night. Expect reduced cigs
AoB 4000 to 5000ft for much of that day with visibilities
dropping down to IFR flight conditions or worse within heaviest
showers. Winds increase through the afternoon, with sustained
winds up to 25 to 35kts across southern panhandle TAF sites by 00z
Wednesday through 12z Wednesday. Biggest aviation concern through
the period will be stout southeasterly turning easterly LLWS
around 30kts by 00z, increasing up 45kts through 12 for southern
coastal TAF sites like Sitka, Klawock, and Ketchikan as front and
parent low push up the eastern Gulf of Alaska.
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&&

.MARINE...
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Winds and wave heights are on an upward trend through Tuesday as
a gale force front moves through the gulf with the parent low
staying around 200 NM offshore in the eastern Gulf of Alaska. The
front will bring areas of severe gale force winds (41-47 kts) with
the possibility of gusts exceeding storm force (48-55 kts) along
the leading edge starting this afternoon. Gale warnings are in
place through late tonight off the coast, in Cross Sound, and in
Clarence and Sumner Strait. Winds in the southern panhandle are
expected to turn south to south easterly, while the central
panhandle will have more easterly winds out of Cross Sound, Icy
Strait, and behind Douglas Island. Lynn Canal`s southerly winds
will lie down and switch northerly as the front approaches,
promoting fresh to strong breezes due to the tightening gradient.
Point Couverden could be the big winner in the inside channels,
with easterly winds from the back side of Douglas combining with
the northerly wind from Lynn to form a tip jet, which could exceed
40 kts.

Seas will build strongly with the front, possibly exceeding 20 ft
significant wave height around 20 NM off the coast of Cape
Edgecombe. Small craft advisories are in place through the inner
channels of the central panhandle, as well as Stephens Passage.
There is an area of uncertainty in Cross Sound where NE gale force
winds meet the front-drive southerly swell, which could raise
wave heights to higher than expected. Winds are looking to calm
down through Wednesday afternoon.
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&&

.AJK WATCHES/WARNINGS/ADVISORIES...
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PUBLIC...Winter Weather Advisory until 1 PM AKDT this afternoon for
     AKZ317.
     Winter Storm Watch from late tonight through Wednesday afternoon
     for AKZ319.
     Strong Wind late tonight for AKZ323-330-332.
MARINE...Gale Warning for PKZ022-035-036-641>644-661>664-671.
     Small Craft Advisory for PKZ021-031>034-053-651-652-672.
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&&

$$

SHORT TERM...Contino
LONG TERM....GFS
AVIATION...NM
MARINE...ZTK

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