562
FXAK67 PAJK 080558
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
958 PM AKDT Mon Jul 7 2025

.UPDATE...Updated Aviation section for 6z TAF issuance.

&&

.SHORT TERM.../Through Tuesday night/...The axis of a broad weak
trough & a weak area of low pressure at the SFC is centered
across the central Panhandle. This trough & weak low center
continues to track northeastward across the Inner Channels through
tonight while continuing to weaken. At the mid-levels, there is a
low center located over the northeastern Gulf. Positive Vorticity
Advection will cause showers across the area to be enhanced from
the added lift and will be greatest along the southern & central
Outer Coast, tonight. Only slight chances for thunderstorms are in
the forecast for that timeframe for those areas. Temps at 850mb
of less than 0 deg. C & model fcst CAPE values of up to around 100
to 150 J/kg will be present for that timeframe. Although, LI
values are not quite conducive for thunderstorm. Therefore, the
chances are only slight. Showers in these areas may have some
heavier rates and gustier winds. Rainfall totals through tonight
are greatest around Kake & along the western slopes of the Coast
Mountains from Juneau southward with values of between around 0.35
to 0.9 inches. In addition to cloud cover, the low pressure
system has brought with it some cooler air aloft as has been seen
with the cooler SFC high temps over the last day or so, outside of
some areas that got sunny breaks, which broke 60 deg F, today.

.LONG TERM...
Key messages:
- A surface ridge allows for a decrease in precipitation Wednesday
  before the next system.
- Another low in the gulf brings moderate to heavy rain toward the
  entire panhandle Thursday into Friday.
- Gale force winds along the NE coast and near Dixon Entrance.

Details: The main impact in the long term forecast remains focused
on the plume of moisture over the panhandle Thursday into Friday.
Ahead of this system, a ridge over the gulf will make for a slight
break in rain. Rain will begin to diminish Tuesday night into
Wednesday. During this time, onshore flow will continue allowing for
short times of light showers. Through Wednesday afternoon into
evening, breaks in the clouds will allow for additional heating.
These breaks of broken to scattered clouds will mainly occur over
the central to southern panhandle.

Early Thursday, a low moves into the western gulf that will send a
warm front toward the panhandle. This low, with the help of an upper
level jet, will also send a plume of increased moisture toward the
panhandle. This plume of moisture will bring widespread
precipitation with times of heavy rain. Confidence in this system
has continued to increase with a rise in IVT values and with more
indications from the Extreme Forecast Index (EFI) tables. Multiple
ensembles are now showing the likelihood of >500 kg/m/s of
integrated water vapor transport moving over the panhandle. Moderate
to heavy rain rates will be occur throughout the panhandle, with the
heaviest rates focused on the southern panhandle. For most of the
southern panhandle, including Ketchikan, the NBM is indicating a 75%
chance of >0.5 inches of rain in just 6 hrs. Near Port Alexander,
there is currently a 45% chance of >0.75 inches in 6 hours. Overall,
in 24 hours, areas across he panhandle will receive 1 to 2 inches of
rain, with southern Baranof Island and higher elevations receiving
up to 3 inches. Currently, no flooding impacts are expected, but
increased snow levels with heavy rain rates can lead to rises in
rivers and creeks to bank full.

This low will also bring gale force winds of 35 to 40 kts toward the
NE gulf with the strongest winds near Kayak Island. Other areas will
see increased winds to strong breezes of 25 to 30 kts along the
outside marine waters. Inner channels winds increase up to 30 kts
with the strongest at ocean entrances and in Clarence Strait near
Dixon Entrance. Land areas in the southern panhandle will experience
wind gusts around 35 to 40 mph, and areas near Yakutat look to reach
gusts up to 30 to 35 mph.

That being said, the active weather continues for SE AK into next
weekend as onshore flow with a few embedded shortwaves keep the
panhandle damp. Stay tuned as we will continue to update the
forecast ahead of this system.

&&

.AVIATION...It is still the tale of two panhandles this evening,
with a VFR BKN to SCT layer across the Yakutat over to Haines and
Skagway, and MVFR to IFR CIGs across the southern half of the
panhandle. At time of writing, a frontal feature with an embedded
low is working its way over the panhandle, driving much of the low
CIGs along the outer coast and southern panhandle. Looking at
radar velocity; however, winds aloft are starting to shift to
westerly, which will spread across the entire panhandle. This
moist westerly wind aloft will help deter anyone without an IFR
certification away from west facing mountains. Locations such as
Klawock, Sitka, and Petersburg have the highest likelihood of
heavier rain showers, dropping both CIGs and VIS down to IFR
conditions. Not expecting widespread constant IFR conditions, but
will mostly be a challenge for the immediate 6 hour period of the
TAF issuance.

As the surface low moves NE into Canada, MVFR conditions and rain
showers will move northward, keeping with the westerly wind idea.
Most notably, Juneau CIGs are expected to drop as showers move up
along with the surface low.

Not expecting much in terms of wind shear, but do expect a shift
from surface winds to westerlies aloft at 2000 ft.

&&

.MARINE...Inside Waters: A weak low center currently moving over
the central Inner Channels is causing winds to increase up to
Small Craft level (25kt) for Clarence Strait, today. As the low
weakens further, continues to pass over the central Inner
Channels, & departs the Panhandle, expect winds to become light
to around 10 kt and become more variable in direction. For the
Thursday into Friday timeframe, another much stronger frontal
system will approach the Panhandle / Inner Channels with a
relatively tight pressure gradient, bringing in up to around 25 to
30 kt Small Craft value winds & seas up to 6 ft(higher near ocean
entrances) primarily for the central & southern Inner Channels
from Icy Strait, southward.

.Outside Waters: As the weather system continues to weaken &
depart the Panhandle, winds over the eastern Gulf will continue
to trend down to mainly between 10 & 20 kt through the period out
of a generally westerly to southwesterly direction. Along with
some scattered showers, only a slight chance of thunderstorms
remains in the forecast for portions of the central & southern Outer
Coast through tonight. Seas at the Gulf buoys are reporting 5 ft
with a period of around 16 sec & a southerly swell, which will
turn more southwesterly as we progress through tonight & Tuesday.
A much stronger frontal system will approach the the region for
the late Wednesday night into Friday timeframe, bringing up to
40 kt Gale sustained winds with its much more tightened pressure
gradient & up to around 15 to 17 ft seas.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...None.

&&

$$

SHORT TERM...JLC
LONG TERM....EAB
AVIATION...NC
MARINE...JLC

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