Graphical Hydro Meteorological Discussion

650
FXAK68 PAFC 041341
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
541 AM AKDT Thu Jun 4 2026

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Today
through Saturday night)...

Expect another warm summer day today compliments of a ridge that
stretches across most of mainland Alaska. However, a weak shortwave
will skirt the Copper River Basin this afternoon and showers are
expected across the higher elevations this afternoon and evening.

For Friday, the upper ridge will weaken as a trough begins to dig
into Western Alaska out of an Arctic low. This will be enough to
increase shower activity over the Mountains for most of
Southcentral Friday afternoon and evening, though thunderstorms
are not expected.

Saturday will usher in a return to more clouds and increased chances
of rainfall due to the continued development of the trough.

&&

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

Key Messages:

* Red Flag Warnings issued for the Inland Bristol Bay and Lake
Iliamna zones from 1 PM AKDT this afternoon through 9 PM AKDT
this evening.

* A cooling trend, along with elevated minimum relative
humidities begins Friday and lasts into the weekend across
Southwest Alaska.

Discussion:

The dry and warm pattern will continue across interior Southwest
Alaska for today. Surface high pressure in the Bering along with
surface low pressure in the interior of the state will cause the
pressure gradient to tighten somewhat beginning this afternoon.
North to northwest winds of 10 to 15 mph with gusts up to 20 mph
at times are likely across Inland Bristol Bay (New
Stuyahok/Koliganek) as well as Iliamna and surrounding locations
this afternoon into this evening. These winds, in conjunction with
temperatures in the middle 70s and RH values in 20s percent will
present another hot, dry, and windy fire weather threat today.
With this, Red Flag Warnings have been issued for the Inland
Bristol Bay and Lake Iliamna zones from 1 PM AKDT this afternoon
through 9 PM AKDT this evening.

A cooling trend across Southwest begins Friday and lasts into the
weekend. Temperatures by this weekend look to drop back into the
low to middle 60s for highs. Shower chances return for portions of
Bristol Bay and the Kuskokwim Valley Saturday into Sunday as a
series of weak upper- level shortwaves will move overhead.

Farther out west, a weak North Pacific low will send its front
northward into Adak/Atka by Friday and will result in a period of
light rain. Rain should taper off by Friday evening across the
area as the front pivots back to the southeast. After the front
moves away from the Central Aleutian Chain, higher pressure builds
back in with more quiet weather anticipated across the Bering and
Aleutians through the weekend. The only challenge will be where
low stratus and overcast conditions develop.

&&

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

Through the end of this weekend and into early next week,
relatively cooler and wetter weather is expected to roll in as
Arctic troughing gradually digs further south into interior
Alaska. As this occurs, northwesterly flow aloft will help
moderate temperatures closer to seasonal averages. While timing
these shortwave pushes remains the main challenge in the medium-
to- long range forecast, much of the southern mainland will likely
see on-and-off light showery conditions through the period.
Instability has trended lower, so convective activity should be
limited with any storms that do form.

Looking into the North Pacific, an upper-level low will track
across the Southern Gulf on Sunday and into Monday. While this
system shouldn`t have much direct impact on our region, it could
send moisture up into some of the coastal regions of Southcentral
(including the Wrangell Mountains and Price William Sound). By
Wednesday, another North Pacific low builds just South of the
Central Aleutians. This second low appears to take a more
northerly track, potentially bringing more widespread impacts
across the region toward the later half of the week.

-CW

&&

.AVIATION...

PANC...VFR conditions and light winds will persist.

&&

.FIRE WEATHER...

Surface high pressure over the Bering Sea coupled with surface low
pressure across the interior of the state will once again cause
north to northwest winds to increase this afternoon across
Southwest Alaska. The increase increase in winds will have a
drying effect across portions of the southwestern interior,
especially across Inland Bristol Bay where northwesterlies will
downslope off of the Kilbuck Mountains into Koliganek and New
Stuyahok. While temperatures across the majority of Southwest will
be a couple degrees cooler, temperatures are still expected to be
in the middle 70s across the interior. Relative humidities will
also look to fall to 20 to 25, especially for Lake Iliamna and
Inland Bristol Bay this afternoon. There is some uncertainty
regarding how much wind may reach into the Kuskokwim Valley and
along the Western Alaska Range (Lime Village) this afternoon,
which, in turn, also features uncertainty in how dry those
locations might become this afternoon.

For Southcentral: Hot and dry conditions will persist today,
before beginning to moderate for tomorrow. There remains the
potential for northerly winds up to 10-15 mph through the northern
Susitna Valley and northern Copper River Basin late this
afternoon through tonight. The strongest winds may also occur
during the overnight hours tonight. Therefore, it still looks like
the strongest winds and hottest/driest conditions will not line
up temporally or geographically as the strongest winds are also
expected to be through the higher elevations where conditions will
be slightly cooler and a little more moist.

In the end, there are NOT any Red Flag Warnings out for the
Susitna Valley or Copper River Basin, but conditions will not be
too far removed.

By Saturday, fire weather concerns will have abated across
Southcentral as an upper level trough digs into the area and
brings significantly higher RH values and lower temperatures.

&&

$$

687
FXAK69 PAFG 041317
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
517 AM AKDT Thu Jun 4 2026

.SYNOPSIS...
An upper-level, arctic trough continues to rotate over the North
Pole, swinging a series of shortwaves across the state from the
NW. This will continue to provide chances for snow across the
North Slope through the weekend. In addition, this will continue
to allow northwesterly flow to continue across the state which
will set up the potential for seasonably cooler temperatures as
more abundant shortwaves move south across the West Coast.
Meanwhile, another low will be moving east along the south side of
the Aleutians. This will bring the next slight chance for isolated
thunderstorms to the Upper Tanana on Saturday.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...
- Warmer temperatures reaching the low to mid 70s over most of the
Interior valleys through the end of the week.

- Scattered showers are possible for the Alaska Range, Eastern
Interior, and Northern Interior through the weekend and early
next week.

- Below normal temperatures this weekend, going into next week.
Minimum temperatures may get as low as the mid to upper 30s.

West Coast and Western Interior...
- Warmer temperatures with highs in the low to mid 70s through the
end of the week.

- Strong west to northwest gusts Kotzebue Sound through Friday
night with gusts up to 30 mph expected. Gusts are expected to
relax overnight before picking up again during the day.

- Below to much below normal temperatures this weekend and going
into next week. Minimum temperatures may get as low as the mid
to upper 30s.

North Slope and Brooks Range..
- Below average conditions are expected to persist with
temperatures mostly between 30 and 40 degrees through Friday.

- Isolated snow showers expected to continue across the North
Slope through the start of the weekend. Accumulations
around an inch with higher amounts at elevation in the Brooks
Range.

- Gusty north/northwest winds, up to 30 mph, will remain in place
over the Brooks Range through Friday night.

- Below to much below normal temperatures this weekend and going
into next week. Minimum temperatures possibly dropping below 20
degrees along the coast.

&&

.FORECAST ANALYSIS AND DISCUSSION...
Fairly benign weather continues across most of the state. The
main driver for this forecast period is an Arctic low, currently
sitting over the North Pole, and high pressure out in the Bering.
This is setting up west/northwest flow across the majority of the
state, which will eventually lead to seasonably cooler
temperatures by the end of the weekend. Meanwhile, a series of
weak shortwaves embedded within the flow will move SE from the
Chukchi, over the Brooks Range, and into the NE portion of the
Interior. This will continue to provide chances for snow showers
across the Arctic Plains over the next several days. A slight up-
tick in the westerly winds is possible along the Arctic Coast
today as the first shortwave moves across the North Slope. As the
week comes to an end, a more prominent shortwave will move south
along the West Coast. This will help to broaden the troughing
across the state. In addition, the Arctic low will slowly shift
south, closer to the Arctic Coast. Another low will be moving
east, south of the Aleutians throughout the weekend. Some of the
energy from this low will work its way across the Upper Tanana on
Saturday bringing a slight chance for an isolated thunderstorm in
the afternoon.

&&

.FIRE WEATHER...
Upper-level ridging is expected to persist through the rest of the
week, leading to a decrease in shower and thunderstorm activity.
Light, isolated showers are possible, but chances of wetting rain
and thunderstorms remain unlikely. High temperatures are expected to
remain in the 60s and 70s everywhere except the North Slope where
areas will remain in the 20s and 30s. Minimum relative humidities
are expected to generally be in the 30% range, except the Tanana
Valley, Fortymile Country, and the Yukon Flats where 20% is
possible.

A pattern shift is expected towards the end of the week
and into the weekend as upper-level troughing builds into the state
from the north, leading to the increased possibility of isolated
showers and thunderstorms returning as shortwaves move into northern
Alaska. These showers will also lead to an increase in minimum
relative humidities and decreasing high temperatures this weekend
and into the beginning of next week.

&&

.HYDROLOGY...

No changes from the previous hydro forecast discussion.

Sagavanirktok River: Some overflowing is occurring; however, breakup
along the Sag River has not begun yet. Temperatures continue as
below normal, around the low 30s for a high near the coast and
the mid to upper 30s for the northern Brooks Range. Going into the
weekend and into next week, much below normal to possibly record
breaking temperatures with lows possibly below 20 degrees and high
temperatures not exceeding freezing, except near the Brooks Range
where temperatures may reach the upper 30s.

&&

.EXTENDED FORECAST DAYS 4-7...
At the start of the extended forecast period Sunday a very large
upper level low over the high Arctic continues to push south towards
the North Slope. This low brings very cold air for the time of year
over much of Northern Alaska and puts a definitive end to the warmer
weather of the previous week. High temperatures fall into the upper
50s to low 60s across much of the Interior and fall below freezing
along the Arctic Coast. Interior valleys could see frosts with low
temperatures falling into the 30s. If skies are clear enough
temperature inversions will develop that may bring low temperatures
in the deepest valleys near freezing.

Otherwise daily afternoon showers and the occasional extremely
isolated afternoon thunderstorm are possible across the Interior
under this pattern. Heavier and more widespread precipitation is
most likely only when stronger shortwave features rotate around the
Arctic low into the region. When these pass through northwesterly
winds along the West Coast, particularly the Chukchi Sea Coast, and
westerly winds across the Arctic Coast are expected to increase.
Combined with the low temperatures unseasonably cold wind chills are
possible across the Arctic Coast early next week. The timing of
these stronger shortwave features is still subject to change, but
the current forecast is predicting one passing through the region
Sunday afternoon through Monday which is expected to bring those
more widespread showers and stronger winds.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Small Craft Advisory for PKZ801.
Small Craft Advisory for PKZ805-806-853-854-856.
Brisk Wind Advisory for PKZ807.
Brisk Wind Advisory for PKZ808.
Brisk Wind Advisory for PKZ809.
Brisk Wind Advisory for PKZ810.
Brisk Wind Advisory for PKZ814-860.
Brisk Wind Advisory for PKZ815.
Small Craft Advisory for PKZ850.
Brisk Wind Advisory for PKZ855.
Brisk Wind Advisory for PKZ861.
&&

$$

Twombly
Lewis - Fire Wx
Stokes - Extended

407
FXAK67 PAJK 041838
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1038 AM AKDT Thu Jun 4 2026

.UPDATE.../to add the 18Z aviation discussion/...

&&

.SYNOPSIS...

Key Messages:

-Rain returns to the northern panhandle on Thursday, as a front
moves through

-Chances of showers linger into the weekend.

&&

.SHORT TERM.../Through Friday/...Rain is spreading northward as a
cold front slowly moves across the panhandle, with precipitation
likely to reach the Icy Strait Corridor by the afternoon hours.
Although PWATs of ~0.2 to 0.3 inches will help keep precip largely
limited to light to moderate, rainfall amounts of between 0.5 to
1 inch still look possible over the next 48 hours (through
Friday). The frontal band will stall over the Icy Strait Corridor
by Thursday evening before slowly sagging south and weakening
through Friday. Expect some chances of showers to linger even as
the front dissipates due to onshore flow as the parent low,
currently situated S of the panhandle, slowly moves off the E and
into British Columbia over the weekend. In its wake, a narrow
ridge will begin to rebuild across the eastern Gulf through the
weekend, for additional information, see the long term discussion.

Low temperatures will be moderated through the next few days, as
cloud cover keeps many areas in the upper 40s or the 50s during
the overnight hours. The cloud cover will also keep high
temperatures muted however, with high temperatures in the 50s and
60s becoming the default for the remainder of the week. Surface
winds will exhibit occasional breeziness and periods of more
gusty winds as frontal bands continue to advance north, though
given the distinct lack of strong dynamic support this far north
of the parent low, am expecting wind gusts to cap out for most
locations at ~20 to 25 kt, with Skagway being the exception which
could see stronger winds, as southerly flow is funneled through
Taiya Inlet.

.LONG TERM.../Saturday through Tuesday/...Surface ridging looks
to shift slightly south and east of the panhandle on Saturday,
with weak onshore flow allowing for light rain showers and cooler
temperatures. For Sunday onward, deterministic and ensemble
guidance widely varies between models and model run to run
differences with the handling of the next system traversing
through the Gulf. GFS and especially Canadian guidance favor
sliding the low south of Haida Gwaii, with drier offshore
conditions north across the panhandle. However, the GFS ensemble
trend has tracked a bit further north and more online with the EC
deterministic and ensemble guidance, which brings the low further
north into the eastern gulf with with multiple troughs/fronts
pivoting north through the panhandle. Have leaned towards the EC
solution and bring rain into the panhandle, although cap PoPs as
confidence in this solution is only moderate this far out due to
the large spread in model guidance. The best potential looks to
remain south of the Icy Strait corridor. Keep a chance of showers
into Tuesday, although the trend is looking to be drier as most
guidance has the low shifting southeast of the panhandle with
ridging building back in behind it.

Southeasterly flow looks to increase ahead of the low over the
weekend, possibly reaching small craft criteria along the outer
coastal waters and inner channels, especially into Clarence Strait
on Sunday. Seas also trend up in the eastern Gulf and ocean entrance
of the southern inner channels, possibly climbing to 10 ft. A
downward trend in marine conditions is expected early next week as
the low shifts off to the south and east.

&&

.AVIATION.../Until 18z Friday/...Bands of rain showers & lower
CIGs originating from an area of low pressure centered to the
southwest of the panhandle are continuing to move from south to
north over the Southeast Alaska region. This will continue on &
off through the TAF period. These bands will periodically lower
CIGs & VISs down to within the MVFR flight category through the
period. SFC winds will be on the rather breezy/gusty side through
this evening for the northern Lynn Canal(PAGY & PAHN) area,
especially for PAGY, due to a tightened north to south pressure
gradient in place over that area. SFC winds look to become a
little bit elevated for the PAKT area through this afternoon, as
well. LLWS values remain relatively benign through the TAF period.

&&

.MARINE...A low S of the panhandle will slowly move E into BC
through the remainder of the week. A remnant frontal band from the
low will linger over the panhandle before falling apart through
Friday. A ridge begins to build over the E Gulf over the weekend.

Outer Waters: Small craft advisory seas build over the southern
Gulf Thursday as a low S of the panhandle traverses E. Seas begin
to diminish by late Thursday night. By Friday, seas in the outer
coastal waters of 5 to 7 ft are expected. Seas will remain 5 to 7
ft until Sunday when wave heights build back to 8 to 10 ft. SW
swell of 2-4 ft on Thursday, with the largest swell in the
southern outer coastal waters. Swell diminishes to 1-2 ft on
Friday.

Inner Waters: Winds over the inner waters will fluctuate between
10 to 15 kt through the day, with wind speeds spiking upwards as
frontal bands move through. Lynn Canal and Clarence Strait will
likely remain on the stronger side, with these areas in particular
likely to see winds of up to 20 kt - or even 25 kt in the case of
the Clarence Strait ocean entrance.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ036-641-661-662.

&&

$$

SHORT TERM...GFS
LONG TERM...DS
AVIATION...JLC
MARINE...GFS

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