Graphical Hydro Meteorological Discussion

726
FXAK68 PAFC 091258
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
458 AM AKDT Sun Aug 9 2026

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Today
through Tuesday night)...

A large and deep upper level low is diving southward across the
central Bering Sea leading to amplification of a downstream ridge
over southern AK. Multiple stable layers associated with the ridge
has led to a hodgepodge of clouds across Southcentral and the Gulf
of AK. Widespread low clouds and fog can be found across much of
the Gulf waters, with more localized areas being observed across
the Kenai Peninsula and coastal Southcentral (including Cook Inlet).
Otherwise, the weather is quite benign.

The upper level high will remain centered over the Kenai Peninsula
and Cook Inlet region today before retrograding westward to
interior Southwest AK on Monday. Southcentral can expect a very
similar day to Saturday, with any morning fog or low clouds
quickly burning off and leading to a partly to mostly sunny day
and warm day, with temperatures in the 60s along the coast and 70s
inland. Afternoon/evening showers will be limited to the
northeastern Copper River Basin, along the Tok Cutoff and areas
north of the Wrangell Mountains. As the ridge shifts west on
Monday, a series of weak short-waves will track from the Interior
southward across Southcentral. This will lead to a slight uptick
in afternoon/evening showers over the mountains. Stable conditions
along the coast and valleys will maintain the dry weather and
sunshine.

On Tuesday the upper level ridge will lift back toward Southcentral,
causing low level flow to shift from northerly to southerly. This
will likely lead to a more significant push of the marine layer
onshore, especially up Cook Inlet and the western Kenai Peninsula
to Anchorage and the Mat-Su. Thus, it could end up being an
overcast day with notably cooler temperatures. Meanwhile, with
a light wind regime and little change in the overall pattern,
widespread fog and stratus will persist across the Gulf coastal
and offshore waters.

-SEB

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Today through Tuesday night)...

Looking at the upper levels this morning, the main features
continue to be the upper low drifting south across the Bering Sea
and the ridge centered over the Kenai Peninsula extending westward
into Southwest Alaska. As the low sags southwards across the
Bering Sea through Monday afternoon, expect areas of light rain
along the Kuskokwim Delta coast from Toksook Bay to Kipnuk to
taper off this morning while rain continues for the Pribilof
Islands and the eastern Aleutians throughout the day today. In the
Bering and under the ridge across Southwest, fog and low stratus
will likely linger through this morning into this afternoon. After
the low departs south into the North Pacific for the latter half
of Monday, higher pressure will build in across the eastern
Bering. For the western Bering, a weak front moves in Monday
morning, followed by a strengthening low pressure system by Monday
evening. There remain some timing and positional differences with
this incoming low, especially as models struggle to represent how
it develops as it approaches the central Bering.

For Southwest Alaska, the main focus remains on warmer
temperatures under the influence of the ridge, with highs in the
mid to upper 70s for all but the immediate coast for Monday and
Tuesday. High temperatures for today (particularly for Bristol Bay
and Kuskokwim Delta communities) may similarly be limited as they
were yesterday by the clouds and fog lingering into the
afternoon, with temperatures peaking in the low to mid 60s for
much of the region.

The other thing to watch will be the potential for showers
(perhaps even strong enough to squeeze out a few lightning
strikes) to develop in the afternoons. There looks to be enough
surface- based instability to support this, especially along the
slopes of area mountains. However, overall conditions are not
supportive of strong convection or of thunderstorms: subsidence
under the ridge will likely suppress the growth of convection,
there is a distinct lack of strong upper level forcing, and low-
level winds will likely be too weak to produce longer-lived and
more organized storms. As such, while chance of lightning is non-
zero, it looks to be low for the coming days with the greatest
chance on Tuesday.

&&


.LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)...

A Gulf low is set to bring rain and wind for the Alaska Peninsula,
Kodiak Island, and parts of Southcentral Wednesday through
Thursday. There is higher confidence (50%) of reaching significant
rainfall thresholds in the Alaska Peninsula, with lower confidence
in Southcentral. This is due to a blocking pattern that is in
place from a ridge over the Alaska Panhandle. A stronger or
further west ridge would prevent additional moisture from reaching
Southcentral. Showers are expected to reach Southwest from the
Gulf low.

The pressure difference from the system and ridge has the potential
to generate winds sustained at 40 mph, especially in the Shelikof
Strait. The southern tip of Kenai Peninsula also has a chance
(lower confidence) to see hazardous winds.

The Gulf low weakens and continues to generate showers for
Southcentral, Southwest, and Alaska Peninsula Friday through
Saturday. Despite the precipitation, Southcentral will see above
average temperatures from Wednesday through Saturday from the
ridge. Western Southcentral has the best chance of seeing breakage
of clouds.

A Bering low will bring wind and rain through Friday from Shemya
to Atka. There is significant model disagreement of the track of
this low. The GFS has it continuing to track down the Aleutians
until Sand Point Saturday night versus the Euro which exits the
low across the North Pacific. Ensemble models agree more with the
GFS at this time.

-SS

&&

.AVIATION...

PANC...The potential for patchy fog and low stratus will stick
around again this morning, possibly leading to a short period or
two of MVFR or lower conditions in and around the terminal.
However, daytime heating will help mix out any fog and stratus by
the late morning to early afternoon hours, similar to the past
couple days. Aside from the early day threat for fog and stratus,
VFR conditions and light winds will persist.

&&


$$

726
FXAK69 PAFG 091355
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
555 AM AKDT Sun Aug 9 2026

.SYNOPSIS...A weakening SFC low off the NE Arctic Coast continues to
push east-northeastward away from the area as its influence exits
the eastern North Slope with rain showers exiting & clouds
decreasing. Another area of low pressure that originated from
Siberia continues to move southward with the center staying well off
the West Coast. This will continue bring isolated to scattered rain
showers for that area through the Sunday morning hours with our
southwestern coastal zones like the southern Seward Peninsula,
Norton Sound, & the Yukon Delta coast having the highest
likelihood of seeing rainfall through Sunday morning before it
exits our area of responsibility & gets far enough away from the
region to have much further impact. Overall, next week will be
quite a bit warmer, clearer, & drier with general high pressure
over the entire area. Also, some isolated afternoon & evening
thunderstorms may pop-up over the Western Interior area & near the
West Coast as we get into mid-week from a weak disturbance &
ample daytime heating.

&&

.KEY MESSAGES...

Central and Eastern Interior...

- A few isolated to scattered rain showers will be possible Monday &
Tuesday as a quick moving disturbance drops south across the area.
Any rainfall will be on the light side.

- Temperatures warm steadily starting Sunday through next week with
highs climbing into the mid 70s to around 80 for the middle to
latter part of the week.

West Coast and Western Interior...

- Rain showers will continue into Sunday morning along the west
coast and across parts of the Western Interior. Rainfall amounts
will be light.

- A warm-up is on the way starting early next week as high pressure
provides for a drier weather pattern. High temperatures will reach
well into the 60s, approaching 70, along the coast with mid 70s to
around 80 across the Western Interior.

- Spotty showers will redevelop from the YK Delta to the Seward Penn
by midweek as additional disturbances try to move northward from the
southern Bering. Some isolated thunderstorms will also be possible
across portions of the Western Interior & near the West Coast.

North Slope and Brooks Range..

- Coastal portions of the North Slope will continue to see low
clouds and areas of fog through the weekend along with temperatures
in the upper 30s and lower 40s for the more eastern areas.

- Temperatures will rebound along the North Slope next week with
highs returning to the 50s & 60s along the coast and 60s into the
70s further up the slope as mainly dry weather prevails.

&&

.SHORT TERM.../Sunday through Tuesday Night/...A weakening low
just off the the NE Arctic Coast is continuing to push east-
northeastward & away from that area. At this point, its mainly
bringing increased cloud-cover & isolated very light rain showers
for Sunday for the far eastern North Slope. The weak low that
originated in Siberia continues to move southward, staying well off
the western Alaska coast as it continues to push toward the
Aleutians while continuing to weaken. As it continues to pass by
Sunday morning, it will continue to bring some rain showers from the
southern Seward Peninsula through Norton Sound & through the Yukon
Delta Coast area. It will cross over the Aleutians Sunday night &
get absorbed into another stronger low in the western Gulf on
Monday. A general warming & drying trend takes place, particularly
for the latter half of the weekend, as a ridge of high pressure
begins to dominate from east to west, bringing clearing skies & warm
air advection over the region as can easily be seen with the 850mb
model temperature forecast.

&&

.LONG RANGE.../Wednesday through Saturday/...The GFS & ECMWF
ensemble member spread has improved for next week for exactly where
& how strong the combined low that was mentioned at the very end of
the Short Term section will be that sets up over the northwestern
Gulf of Alaska, but model consensus looks like it will be that it
will drift northward, crossing into the Bering, once again, while
falling apart. Besides that, general ridging sets up over the state,
bringing with it decreasing cloudiness & warming SFC temperatures
across our region with decent warm air advection 850mb temperature
anomalies reaching around +3 to 6 deg C for next week, bringing high
temperatures up to between the lower 70s to around 80 south of the
Brooks Range & into the middle-60s for the western half of the North
Slope. The main change that we made to the forecast was to bring in
some chances for some isolated thunderstorms from daytime heating
for the western interior into the West Coast area for Wednesday
afternoon into the evening hours as CAPE values look to be high
enough & LI values look to be low enough as a weak disturbance also
pushes over that area.

&&

.FIRE WEATHER...For the latter half of the weekend through midweek,
conditions will warm & dry again across the entire forecast area
with high temperatures in the mid-to-upper 70s, approaching around
80 for some areas in the western & eastern Interior. At the same
time, high temperatures will warm into the 60s across the western
North Slope, spreading eastward as we progress to midweek, getting
into the 70s for only the inland portions of the North Slope for
Wednesday through the end of the week. Isolated popcorn
thunderstorms from the daytime heating are possible for the western
Interior & westward toward the west coast for Wednesday afternoon
into the evening hours. Afternoon minimum RH values will gradually
along with the warming temperatures through the week with eastern
portions of the eastern interior like 40 Mile Country, Northway, &
around the ALCAN HWY dipping to around 25-30% for late in the
workweek. Winds should remain on the lighter side.

&&

Coastal Hazard Potential...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...None.

&&

$$

SYNOPSIS...Chambers
KEY MESSAGES...Chambers
SHORT TERM...Chambers
LONG RANGE...Chambers
FIRE WEATHER...Chambers

413
FXAK67 PAJK 092241
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
241 PM AKDT Sun Aug 9 2026

.SYNOPSIS...

Key Messages:

-Suicide Basin glacier dammed lake continues to fill. At this
time, it is expected to be full sometime August 11th or 12th. In
the past, it has taken up to 6 days for the main flooding event
to start after the basin is full. Visit
weather.gov/ajk/suicidebasin for more information.

-Some areas of clouds and a gradual warming trend expected through
the week for the panhandle.

&&

.SHORT TERM...Relatively quiet weather continues. General flow at
mid and upper levels has turned to a mostly offshore N to NE
direction while low level flow is more NW or W. As a result most
of the panhandle is seeing more and larger holes in the cloud
cover this afternoon. The most cloud cover is still over the
Juneau and Icy Strait area where some mid level convergence is
keeping mid level clouds around.

Through the early part of the week, areas of clouds will stick
around but substantial holes in that cloud cover will still
develop due to overall light offshore flow. Some marine layer low
clouds will also plague the outer coast late at night and in the
mornings with some possible fog at times. The light offshore flow
will also continue to bring in a slightly warmer air mass. 850 mb
temperatures will be slightly warming through the next few days
from around 6c today to around 8c by Tuesday. This will result in
afternoon high temperatures showing a gradual warming trend with
upper 60s and low 70s starting to become more common by Tuesday
especially in areas that see more sun. Sea breezes will also
increase with the increased afternoon heating. Winds are likely
to top out at around 15 to 20 kt at most in the afternoons and
evening.

One of the other question marks is the potential for any showers
or thunderstorms to move into the northern panhandle from Canada
this evening and Monday afternoon. Satellite imagery and lightning
detection today have shown a few storms developing in the Southern
Yukon as of 1pm. Nothing has come close to the Haines Customs or
White Pass area yet, but the steering flow is still out of the
north so will direct any storms in the southern Yukon to the
south. Higher pops and a slight chance of thunderstorms remain in
the forecast around White Pass and Haines Customs for this evening
and Monday afternoon as convective indices remain good for both
time periods.

.LONG TERM...Wednesday, a closed low south of the Aleutian chain
will reach full maturity, beginning to decay as it lifts north.
Three primary features of interest as this system moves into the
Gulf are: strength of the accompanying surface low, clear/warm
over the Panhandle for the mid to end of the week, and moisture
transport into the region by the weekend. Touching on the low
first, ensembles show agreement that this system will make
landfall along the AK Peninsula, with southerlies building in the
central Gulf; winds remain below gale force. Our stubborn high
over the eastern Gulf cedes territory, making a slight retreat
into the Panhandle, with north-westerlies still impacting much of
the coastal waters. Overall, little concern for major marine
impacts with continued focus for northwest winds of moderate to
fresh breezes along the Alexander Archipelago and sea breezes thru
the inside.

As this high shifts into the Panhandle Thursday, warm and dry
once again becomes the theme. Digging into the 850mb temps, the
LREF shows a left-skewed distribution based around 7C to 15C, with
the mode around 13C, translating to 75F to 85F surface temps,
about 10F above normal for this time of year. The Extreme Forecast
Index shines more light into this, with agreement in abnormal
warmth increasing its footprint over the Panhandle into the end of
this week. A note, its not just about the afternoon high
temperatures, nightly low temperatures also likely remain about
10F above normal for most of the region.

Moving onto moisture, by the end of the weekend this pattern will
begin to break down the dominant high, or at a minimum, push the
ridge further east, with southwesterlies picking up on some
equatorial moisture and funneling it into the Gulf. A few ensemble
outliers want to bring a quick hit of moderate AR conditions;
however, overall modest Integrated Vapor Transport values suggest
just an increase in clouds, and perhaps some light rain, by the
end of the weekend.

&&

.AVIATION.../through 00z Tuesday/...Upper level system remains
stationary over the Panhandle this afternoon with CIGs having
lifted to predominantly VFR with some weak localized sea breezes
finally developing as of this discussion. With the surface high
parked over the central Gulf in tandem with the upper level low,
broken to overcast skies and unsettled weather are still expected
to continue through the TAF period though probability of any
impactful showers reaching the panhandle remains low. Conditions
will remain benign through the afternoon and evening, however
diminish routinely overnight AoB 2000ft as marine layer settles in
and light rain or drizzle returns, particularly for the outer
coast sites.

Similar to previous days, winds of sustained 10 to 15 kts will
continue through this afternoon, with the highest chance of seeing
any gusts reaching 20 kts being in the vicinity of Taiya Inlet.
No LLWS concerns through the TAF period.

&&

.MARINE...
Outside: A 1023mb high pressure remains stationary over the
central Gulf into early next week, keeping generally overcast
skies with light and variable winds along in the outer waters.
Wave heights remain largely benign through the early week, around
4ft or less along the coast with a persistent southerly swell of
2ft or less. Accompanying this high pressure is broad westerly to
northwesterly winds in the NE gulf coast down to Dixon Entrance
around 10 to 15 kts or less, with the strongest winds expected in
the vicinity of Cape Spencer and Cape Decision, particularly by
the afternoon hours. Main marine concern for outer and coastal
waters will be nightly return of marine layer, dropping
visibilities potentially as low as one quarter mile each morning.

Inside: Conditions across the inside waters remain relatively
benign this afternoon with only a few areas seeing winds above 10
kt, namely near ocean entrances as well as localized sea breezes.
This pattern of relatively benign conditions with marine layer
influence and patchy fog in the morning giving way to increasing
winds and sea breezes by the afternoon will hold true through at
least midweek. Wave heights remain 4 feet or less through early
week as well with no significant systems to break down the
influence of high pressure out in the gulf.

&&

.HYDROLOGY...Suicide basin continues to fill. With the cloudy and
somewhat cool weather we have had over the weekend as well as the
calving event on Friday night, we have moved the expected most
likely date for a full basin to be August 11th-12th. The overflow
channel is still around 1350 ft and we still expect the release to
start up to 6 days after the basin has reached full status.

&&

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

&&

$$

SHORT TERM...EAL
LONG TERM...AP
AVIATION...STJ
MARINE...STJ
HYDROLOGY...EAL

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