Graphical Hydro Meteorological Discussion

602
FXAK68 PAFC 191331
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
531 AM AKDT Tue May 19 2026

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3)...

The overall weather pattern is expected to be much the same over
the next couple of days as several shortwaves continue to pass
over Southcentral. Gusty southerly gap winds will continue
through this evening. Rain showers will pass over Anchorage and
the western Kenai peninsula this morning, otherwise, expect drier
conditions this afternoon. Persistent rain will continue along the
north Gulf coast and southern portions of the Copper River Basin
through Wednesday morning. Additionally, rain showers are likely
in the Susitna Valley through early this afternoon before drying
out. Inland areas will remain drier this afternoon through
tonight before a new low tracking out of the North Pacific moves
toward Southcentral on Wednesday. Winds lighten ahead of this low,
bringing an end to downslope drying and leading to increasing
chances of widespread light rain inland. Southcentral will dry out
again Wednesday night, but a new Bering low will send a frontal
system toward Kodiak and the western Gulf Wednesday night into
Thursday, as the active weather pattern continues.

KM

&&


.SHORT TERM FORECAST SOUTHWEST ALASKA, THE BERING SEA/ALEUTIANS
(Days 1 through 3)...

Nighttime microphysics satellite imagery shows another wave of
low pressure is tracking through Southwest Alaska this morning
while our broader vertically stacked upper low remains centered
just west of the Pribilof Islands. The passage of the smaller wave
through Southwest is contributing mildly gusty southeasterly
winds from the Western Alaska Range into the Kuskokwim Valley.
Gusts are peaking at around 25 mph from Dillingham to Iliamna
while King Salmon is gusting in the 30 mph range. Much of the
stronger winds will diminish through midday to early afternoon as
the wave of low pressure exits the region to the north. At the
same time, however, the vertically stacked low over the Bering
will begin to lift northeastward as an open wave trough and clip
the YK Delta later this evening, resulting in increasing southerly
winds and increasing showers across the Kuskokwim Delta through
tonight.

The next storm system is forecast to take shape later this
evening as a Kamchatka low deepens down into the ~975 mb range
immediately south of Shemya. The low then tracks along the
Aleutian Chain through Wednesday, eventually threading the
Pribilof Islands and Dutch Harbor en route to the Kuskokwim Coast
early Friday morning. Gales will be possible ahead and south of
the low as it moves eastward, with cold air advection potentially
promoting storm force gusts between Atka and Nikolski midday
Wednesday. The low begins a weakening trend thereafter with small
craft winds and higher gusts becoming the primary hazard along and
through the Alaska Peninsula into Thursday.

The lone bright spot in the forecast may be across Southwest
Alaska on Wednesday, as conditions relax and skies clear in-
between the departing Bering Sea low and the arrival of the
deepening Kamchatka low. Until then, scattered showers will be the
norm through tonight with a very low threat of an isolated wet
thunderstorm or two near Lime Village this afternoon.

-BL

&&

.LONG TERM FORECAST (Days 4 through 7: Friday through Monday)...

A broad upper level low anchored over the Bering Sea looks to
continue to remain in place through the long term. Several
shortwaves rotating around this low across the western Bering,
North Pacific, and into the Gulf will continue to support the
active pattern and unsettled conditions across much of southern
Alaska through this weekend.

Models are in good agreement to begin the long term period as the
late week low in the eastern Bering pushes inland into Southwest
Alaska, spreading rain chances across much of the region from the
Gulf into Interior Southwest and Southcentral heading into the
weekend. This system will be quickly followed by a series of two
subsequent low pressure systems lifting out of the North Pacific,
with the first being this weekend and the second early next week.
Models begin to slightly differ on the exact timing and northward
progression of each of these lows, but the ensemble mean consensus
generally has the lows tracking south and along the Aleutian
Chain and into the Gulf. Elevated winds accompanied by light to
moderate rainfall with each system can be expected along the
Aleutians and Alaska Peninsula before pushing into the Gulf, with
the heaviest precipitation expected along the immediate Gulf
coast.

&&







.AVIATION...

PANC...VFR conditions and gusty southeasterly winds are expected
to continue. Light rain will begin this morning and ending by
early afternoon. The gusty conditions will prevail until the
evening.


&&


$$

370
FXAK69 PAFG 191301
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
501 AM AKDT Tue May 19 2026

.SYNOPSIS...
A broad area of low pressure continues over the western portions
of the state. This will allow for multiple waves of precipitation
to move across the Central/Western Interior and West Coast over
the next couple of days. Meanwhile, the positioning of the trough
has set up southerly flow across the Interior. This will allow for
warm, dry, and windy conditions to persist through the middle
portions of the week. However, another surface low will work its
way into the northern Gulf of Alaska, stationing itself in a
favorable setup for some wrap around precipitation into the
Interior starting Wednesday night. In addition, the southerly flow
through coming over the Alaska Range will allow for additional
chances for Wind Advisory Criteria winds through the Alaska Range
passes today and Thursday. High water along the Lower Yukon River
has caused flooding impacts in Grayling, Holy Cross, and Russian
Mission. Flood Warnings have been issued for these communities.

&&

.KEY WEATHER MESSAGES...

Central and Eastern Interior...
- Isolated to scattered showers continue across the Interior,
today, with a non-zero chance of embedded thunderstorms amongst
the showers.
- Best chances for thunderstorms today will be across the middle
portions of the Central Interior.

- Another round of gusty southerly winds are expected through the
Alaska Range passes today. Wind gusts through Isabel and Windy
Pass are expected to be between 45 and 55 mph. A Wind Advisory
is in effect for Isabel Pass and Delta Junction.

- Mostly dry conditions expected across the Interior interrupted
by occasional rain showers. A Red Flag Warning has been issued
for Delta Junction.

- Seasonably warm temperatures are expected to continue across
the Interior through much of the week.

West Coast and Western Interior...
- Gusty S-SE winds are expected across the West Coast this
afternoon with an upper-level shortwave passage.

- Thunderstorm chances for this afternoon shift north over the
central portions of the Western Interior.

- Showery conditions are expected along the Lower Yukon and Yukon
Delta regions throughout the week. Heavier showers are expected
today and Thursday. These showers will be mostly rain,
especially nearer the Western Interior, but some periods of snow
and light wintry mix are possible near St. Lawrence Island and
the Bering Strait Coast.

North Slope and Brooks Range..
- Showery conditions are expected to continue along the southern
portions of the Brooks Range today. Little to no precipitation
is expected across the North Slope.

- Chilly temperatures persist with highs in the 20s and lows in
the teens along the North Slope. A gradient of temperatures
across the Brooks Range with highs in the 50s to near 60 along
the southern slopes and low 40s for the northern slopes.

- Breezy northeasterly winds along the Western North Slope weaken
slightly and shift more easterly. E to ENE winds 15 to 25 mph
are expected across the Arctic Coast through Wednesday.

- Low clouds and areas of fog persist across the Arctic Coast and
will likely remain through much of the week, especially along
the Eastern Arctic Coast.

&&

.FORECAST ANALYSIS AND DISCUSSION...
Not much change to the overall forecast as persistence continues
to hold on strong. The main driver of the forecast continues to be
the Bering low that has slowly been filling in since yesterday
afternoon. Farther north, high pressure continues to linger over
the Arctic. This has resulted in a decent pressure gradient
across the state, with the strongest winds occurring around peak
heating. High pressure is expected to continue over the Arctic for
much of the forecast period, allowing the easterly winds, fog, and
cooler conditions to continue across the North Slope.

A shortwave continues to make its way, NW, toward the Norton
Sound. Guidance shows the surface low to move around St. Lawrence
Island and get wrapped back in to the flow of the trough over the
Bering. As this happens, another low will be moving east along the
Aleutians. Models show this low to gradually weaken as it
progress, reaching Bristol Bay coast sometime Thursday afternoon.
This set-up will allow for the broad troughing to continue across
northern Alaska, which will result in isolated showers and non-
zero chances for thunderstorms through the end of the week.
Compared to the previous low, this one is able to progress farther
east, which will be a better set up for potential gap winds as
bands of energy move across the Alaska Range over the coming days.
The strongest gap winds are expected to be today and Thursday. To
add on, latest model runs have shown the low to fill in slower
with each run, which could help keep the surface gradient tighter
as it moves towards Bristol Bay. This will play more of a role for
the increased wind potential on Thursday. Meanwhile, another low
will move into the northern Gulf of Alaska by Wednesday afternoon.
Models are showing the potential for the low to set up between
the 150 and 140 longitude lines, allowing the potential for wrap
around precipitation into some portions of the Interior.
Nonetheless, the prevailing southerly flow over the Alaska Range
could keep areas north of the range drier with the downsloping.
This, in combination with the previously mentioned gap winds,
could bring Red Flag conditions through Isabel Pass and Delta
Junction today and Thursday when the winds are strongest.

With this next low showing the potential to progress farther east
than the previous one, this will allow for easterly flow to
return across portions of the Northern Interior and Yukon Flats by
Thursday. These will be the best chances for isolated
thunderstorms on Thursday as models are showing cape values to be
around 150 J/kg, which is more than enough to get a pop-up
thunderstorm with the help of topographical forcing. This will
spread across to other portions of the Interior by the end of the
week as a series of lows continue to move into the northern Gulf
of Alaska.

&&

.FIRE WEATHER...
The overall pattern remains mostly the same through much of the week
with a low in the Bering Sea and ridging over Western Canada. This
pattern will continue to support broad southerly flow across the
region. Downsloping effects will work to keep most of the central
and eastern Interior dry and warm with a few afternoon rain showers
possible. Accumulations should remain light with localized higher
amounts expected in southwest Alaska and where thunderstorms are
present. Although chances are low, a non-zero chance for lightning
is possible this afternoon across portions central portions of
the Western and Central Interior. Thunderstorm chances largely
diminish after today with a slight chance for very isolated
thunderstorm development later this week across the Interior,
Brooks Range, and Yukon Flats. Expect high temperatures in the 60s
and lows in the 40s through the week, with min RH values ranging
between 20 to 30% in the central and eastern Interior and 30 to
40% in the western Interior.

The greatest area of fire concern this week will be near Delta
Junction as strong southerly gap winds develop Tuesday and Thursday
through Isabel Pass. Sustained winds between 20 to 30 mph gusting as
high as 55 mph are possible this afternoon with similar
conditions expected to develop again Thursday as the pressure
gradient over the Alaska Range restrengthens later this week. A
Red Flag Warning was issued for Delta Junction beginning this
afternoon through late Tuesday night for a combination of dry
fuels, strong winds, and dry air with min RHs values near 25%. We
will continue to monitor the situation near Delta Junction on
Thursday as conditions are expected to near critical fire weather
criteria once again.

&&

.HYDROLOGY...

Yukon River:
The breakup front on the Yukon has passed Russian Mission. As of
Monday morning, an ice jam was reported downstream of Russian
Mission that has caused water levels to rise. A Flood Warning
remains in effect. Water remains high on the Yukon upriver from
the breakup front due to snowmelt and the Yuki Ice Jam release.
Water has inundated the road to the airport at Grayling and Holy
Cross. Flood warnings have been issued.

High water is expected to continue until the ice jam releases.
Water levels will likely rise near the jam as higher water levels
continue to move downstream towards the jam. Water levels are
continuing to drop at Galena and beginning to drop at Koyukuk. No
additional water level rises are expected at Koyukuk or Galena. As
of 1:50pm AKDT, Monday, the river gauge at Galena shows the water
levels dropping down to 122.6 ft which is below the minor
flooding stage.

Buckland River:
Water levels are falling and the river upstream of Buckland is
open. Open leads have been reported downstream of Buckland and
flooding is no longer expected.

Chena:
The Chena River continues to respond to warmer temperatures with
higher elevation snowmelt leading to rivers running higher than
normal, but likely remaining below action stage.

Additional Information:
Visit www.weather.gov/aprfc for the latest hydro information.

Please report observed flooding to local emergency services, law
enforcement, or to the National Weather Service when you can do so
safely.

&&

.EXTENDED FORECAST DAYS 4-7...
To start the extended time frame on Friday, a front will have pushed
well into the Interior ahead of a low in southwestern Alaska. This
will bring another chance for scattered thunderstorms across a
good portion of the Interior on Friday. High pressure in the
Arctic will allow for persistent easterly winds to blow along the
Arctic coast and northerly winds along the West Coast through the
weekend. Along the front in the Northern Interior and in the
Seward Peninsula/Kotzebue Sound area will be a band of numerous
rain showers, with scattered showers in the Southern Interior in
its wake. Periods of heavy snowfall will also be possible in the
Alaska Range, with gap winds diminishing by mid to late Friday. As
the front crosses the Brooks Range by Saturday morning, snow will
decrease in the Alaska Range, with scattered showers continuing
on the north side, including on the North Slope. Generally warm
conditions will persist throughout the period south of the Brooks
Range, with highs in the 50s and 60s. The West Coast will likely
see highs in the 30s and 40s, with 20s and 30s on the North Slope.
Additional showers will be possible across Northern Alaska early
next week ahead of another potential system in southwestern
Alaska.

Coastal Hazard Potential Days 3 and 4...None

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Wind Advisory for AKZ837-849.
Flood Watch for AKZ826-830.
Red Flag Warning for AKZ937.
PK...Small Craft Advisory for PKZ801-850.
Small Craft Advisory for PKZ812.
Brisk Wind Advisory for PKZ814.
Brisk Wind Advisory for PKZ815.
Small Craft Advisory for PKZ816.
Small Craft Advisory for PKZ817.
Small Craft Advisory for PKZ854.
Brisk Wind Advisory for PKZ860.
&&

$$

Twombly
MacKay - Extended
Santiago - Fire Wx

104
FXAK67 PAJK 191815
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1015 AM AKDT Tue May 19 2026

.UPDATE...Aviation section updated for 18z issuance.

&&

.AVIATION... On shore flow is bringing generally VFR conditions
across the area today. The main exception today has been Yakutat,
which has experienced periods of MVFR due to lower clouds.

Late tonight into Wednesday morning, a front will bring rain chances
and strong winds to the Panhandle. LLWS is expected begin around 08Z
with 30 kts and increasing to 40kts toward the end of the TAF period
for Yakutat. This front will also increase precipitation chances and
wind speeds from west to east across the Panhandle.

Tonight, clearing is expected to lead to fog development for areas
south of Fredrick Sound. The fog will bring us down to IFR
conditions, and will likely stay through the rainfall arriving with
the front around the end of the TAF period. Although, brief
improvement does look possible before the rain arriving with the
front.

&&

.PREV DISCUSSION......ISSUED AT 526 AM AKDT Tue May 19 2026

SYNOPSIS...

Key Messages:

- Brief lull Tuesday with weak ridging over the panhandle and
lingering showers, primarily for the northern panhandle.

- Wednesday a gale force system brings widespread rain to the
region.

SHORT TERM...A weak mid level trough will push into the ridge
over the panhandle Tuesday morning. Satellite observations reveal
little to no breaks in cloud cover over the panhandle. This lack
of clearing limited cooling overnight and subsequent fog
development, with most communities staying just above 40 degrees
as of 5am.

The upper level ridge over the panhandle is still expected to
sharpen Tuesday, giving a better chance for clearing through the
day for the southern panhandle, particularly communities along Clarence
Strait. Isolated showers will still remain possible for the
northern mountains, with breaks over the inner channels.

By late tonight, a developing gale force low will push a front
towards the panhandle. This front will bring deteriorating
conditions to the gulf waters and moderate to locally heavy
rainfall to the panhandle Wednesday. The northeast and outer gulf
coast are currently slated to see the highest storm totals of
around 2 inches in 24 hours, with generally 1 to 1.5 inches
expected for other communities in the panhandle from Cape Decision
northward to Icy Strait. The southern panhandle south of Cape
Decision should see an inch or less over the same timeframe. The
associated surface front is currently expected to push into the
panhandle late Wednesday night into Thursday bringing a westerly
wind shift.

LONG TERM.../ Thursday to Monday /
Thursday will likely be showers or fading shower activity in a post
weather front (Wednesday`s) situation. The associated low feature
near Prince William Sound weakens and will be getting absorbed
during Thursday/Thursday night into the front from a low over
Bristol Bay. The new front sweeps the western gulf Thursday and to
the eastern Gulf of Alaska Thursday night. Yakutat should Good rain
rates Thursday night. The front is forecast to be weakening, as the
feature moves way from the parent low which stayed over Bristol Bay
so the feature that rolls across the panhandle Friday is a frontal
band followed by a ridge over the gulf to the panhandle for the
start of the weekend.

For the Memorial Day Weekend / Saturday to Monday / The models here
are still trying to settle into a pattern. Indications are that a
system will spin into the Gulf of Alaska, mainly for Sunday, however
its intensity and track are uncertain at this point. Ensemble means
and a variety of operational models are trending toward a 995 to
1000 mb low heading in the general direction of Dixon Entrance by
Sunday night, but there are indications the low could be as strong
as 985 mb, and some outliers are pointing toward a much further
south track and weaker low. Overall the weekend may be cool and damp
or could be wet and windy, especially over the southern panhandle on
Sunday depending on how this system evolves.

AVIATION.../through Tuesday night/...Mostly VFR flight
conditions are expected through the period. CIGs 4-6kft could
occasionally dip down to MVFR with weak onshore flow bringing a
few light showers, mainly across the northern panhandle. For PAYA,
showers will become more prevalent through the period, with MVFR
VIS/CIGs becoming likely by this afternoon. Winds will generally
be on the lighter side less than 10kts through the period.
Stronger winds around 10G20kts for PAHN and around 20G30kts for
PAGY as the gradient remains over the northern panhandle.
Decreasing winds and increasing near surface moisture could lead
to patchy fog development tonight, mainly across the southern
panhandle. However, confidence not high enough to bring
significant VIS/CIGs reductions into the 12Z taf issuance. LLWS
will increase for PAYA late tonight as the next front approaches
and winds 2kft aloft become 30-40kt.

MARINE...
Winds continue to diminish in the wake of a front which moved
through on Sunday, although respectable southerly flow will persist
in Northern Lynn Canal through the foreseeable future. A system
moving across the Gulf on Tuesday arrives in SE AK on Wednesday,
bringing gale force winds to the N and NE Gulf Coast, and small
craft conditions to the inner channels.

Outside coastal waters: Winds have diminished substantially in the
wake of the last system, and seas have trended down overnight down
to 6 to 7 ft for most areas based upon buoy observations. Winds
will trend upwards again on Tuesday across the Gulf, and by
Tuesday night for the outer coast, as another system approaches SE
AK. Expect the strongest winds to be largely focused around the
northern gulf and gulf coast, though gale force winds could extend
as far south as Cape Edgecumbe. Waveheights should ramp back up
as this system moves in, reaching 12-15 ft on Wednesday. Winds and
waveheights then diminish late Wednesday into Thursday as the
system departs.

Inside Channels: Similar to Sunday night, winds across the inner
channels diminished overnight Monday into Tuesday. The lone
exception once again was Lynn Canal, where elevated southerly flow
of ~20 kt persist. Winds will ramp back up to 10-15 kt on
Tuesday across the board, as southerly flow is sustained by a
weak wave moving onshore. Wednesday will see widespread sustained
southerly winds of 25 to 30 kt as a strong warm front moves
onshore, alongside elevated seas, with ocean entrances reaching
10+ feet, and areas where swell reaches seeing additional
inclement conditions.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...None.
MARINE...Gale Warning for PKZ652-664-671-672.
Small Craft Advisory for PKZ022-032-033-053-641>644-651-661>663.

&&

$$

SHORT TERM...STJ
LONG TERM...Bezenek/EAL
AVIATION...DS/Musall
MARINE...STJ

Visit us at http://www.weather.gov/Juneau