Sitka, Alaska 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

451
FXAK67 PAJK 201319
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
519 AM AKDT Sun Jul 20 2025

.SHORT TERM...Clearer skies across much of the panhandle and
warmer weather are in store across the panhandle. Satellite
imagery shows a marine layer which has built in across the outer
coast and northern panhandle, while The forecast has remained
largely unchanged from previous thinking - a marine layer which
advanced back into parts of the area overnight will move back
offshore through the day on Sunday, while ridging over the Gulf
keeps away chances of precipitation. Some upper level clouds
occasionally from weak upper level shortwaves moving through,
but nothing substantial in this field. As the marine cloud deck
decays, temperatures will rebound, with many locations reaching
the upper 60s and 70s. Winds will generally remain on the lighter
side, although sea breezes will develop in places like Lynn Canal
and Icy Strait.

.LONG TERM.../Monday through Friday/...A surface high pressure system
in the southern Gulf of Alaska continues to build through the
beginning of the week, slowly moving northwest. A broad upper
level ridge stalls over the central gulf, reinforcing the surface
ridge and helping sustain the high early in the week. This ridging
will funnel more dry air over the panhandle, clearing out skies
and tightening the pressure gradient, increasing wind speeds along
the gulf coast. By Monday afternoon, sustained winds will
increase to 20 kts going into cross sound and along the coast,
with speeds peaking Tuesday evening around 25 kts off the
southwestern coast of PoW. Gusts may reach 30 to 35 kts in Dixon
Entrance. A tightening pressure gradient will bring up wind speeds
from the northwestern gulf, and an ESE direction is conducive to
gap winds coming out from between Kodiak Island and the Kenai
Peninsula. From this, the central gulf can expect to see up to 30
kts of westerly winds with significant wave heights reaching 12 to
13 ft through Tuesday.

High temperatures of between 14 to 16 degrees C at 850 mb with
areas of 17 degrees C and clearing skies indicate warmer surface
temperatures for early next week, raising for Monday and Tuesday.
Interior regions of the panhandle will experience the highest
temperatures, with highs reaching the mid to high 70s and lows in
the mid 50s. Max temp EFI values have stayed consistently high
Monday through Wednesday. NBM probabilities have consistently
indicated a very high potential of reaching 80 degrees in areas of
Skagway, Haines, and Hyder, despite temperature observations
rarely surpassing the low 70s the past few days. These are areas
of known temperature biases for the NBM and other models are only
estimating around a 30% chance just for Hyder, so confidence is
very low on temperatures actually breaching 80.

Clearing skies and warming temperatures will allow for a sea
breeze to develop in some of the inner channels, with winds
potentially reaching 10 to 15 kts near the water in Juneau and
Haines, and 20 to 25 kts in Skagway. Strong winds are expected
through Icy Strait and up Lynn Canal with this sea breeze, peaking
in the mid afternoon. This is also conducive to marine layer
development along the gulf coast which will bring low clouds to
coastal regions and pushing into Cross Sound.

The consistent NW upper-level winds help to pull a deep upper-
level trough down over the panhandle Wednesday. This will assist
the associated surface shortwave trough in strengthening into a
disorganized, yet closed low over the northern gulf coast. The
northern panhandle can expect light rain Wednesday with minor
accumulations of 0.2 inches or less in 24 hours. The central and
southern panhandle will join in Thursday, with potential for light
precipitation continuing into the weekend.

&&

.AVIATION...Flight conditions run the gamut across the panhandle
this Sunday morning. Skies cleared out overnight for much of the
southern panhandle, with just some occasional mid level clouds
slipping through around 3500 ft. Another mid level cloud deck
attempted to slide westward towards Ketchikan but stopped just
short and has since slowly retreated eastward. For the northern
panhandle, mid level clouds persist between 3000 and 4000 ft, and
generally look to stick around for a majority of the day Sunday,
with higher level clouds also rotating through. A marine layer
cloud deck has also developed overnight and impacted both Yakutat
and Klawock, with CIGs down to 500 ft at Klawock. While the cloud
layer in Klawock appears relatively shallow and should be short
lived, Yakutat will likely maintain at least MVFR conditions
through the day Sunday, with lower conditions in the morning hours
due to the marine layer moving onshore. Expect this to retreat
later this afternoon, but return once more Sunday night into
Monday. Overall no LLWS concerns and no significant surface winds,
with strongest being southerly 15 kt at Skagway by the early
afternoon.

&&

.MARINE...Inside waters: Relatively low wind conditions across the
inner channels the next few days with mostly 15 kt or less of
winds (mostly from the N and W) and seas of 3 ft or less in most
areas. Over the next few days, seas breeze circulations will
continue to be the main concern with the stronger seas breezes (up
to 20 kt) expected Sunday and Monday afternoons and evenings, as
temperatures over land warm into the upper 60 and 70s, before
diminishing again overnight.

Outside Water: As a ridge builds over the Gulf, NW winds off
Prince of Wales and Baranof Island increase in response. Expect
around 20 to 25 kt NW winds from around Cape Fairweather
southeastward from Sunday afternoon into Monday morning. Seas off
of Prince of Wales Island will also build in response to the
increased winds likely building to around 7 to 8 ft by Sunday
night. Rest of the gulf will see lower winds (around 10 to 15 kt
out of the W) and lower seas (6 ft or less) through at least
Monday As of early Sunday morning, waves currently ~3 ft with a
16 second wave period and 2 ft SW swell.

&&

.HYDROLOGY...The warmer temperatures across the northern panhandle
expected from Sunday through Tuesday will increase melt water
runoff from glaciers and any remaining snow at elevation later
this weekend and into early next week. This is looking likely to
increase river levels on the Chilkat River to above minor flood
stage by late Sunday night, and while there will be daily
fluctuations, the river may stay at or above minor flood stage
into early next week. A flood watch has been issued for the
Chilkat Valley for the possibility of minor flooding starting late
Sunday night.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Watch from late tonight through Tuesday afternoon for
     AKZ319.
MARINE...Small Craft Advisory for PKZ641-642-661-662.

&&

$$

SHORT TERM...GFS
LONG TERM....ZTK
AVIATION...STJ
MARINE...GFS

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