Graphical Hydro Meteorological Discussion

560
FXAK68 PAFC 200025
AFDAFC

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

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

There is no end in sight for this very active pattern, so expect
continued cloud cover, cooler than normal temperatures, and
generally wet conditions - especially considering this is
typically one of the driest times of year. Starting with the
current analysis, a long-wave trough encompasses all of the Bering
Sea/Aleutians and extends eastward to mainland AK/extends across
the Bering Sea. A deep low which had served as the anchor of the
trough in the Bering has dissipated, but a new deepening low along
the western Aleutians is moving right in and will ultimately take
the place of the original low. A short-wave ridge over the
northeast Pacific is amplifying ahead of a digging short-wave.
This is steering the short-wave crossing the north Pacific
northward toward mainland AK. A surface low has formed ahead of
this short-wave and is tracking northward toward the Gulf.
Meanwhile, a short-wave is tracking northward across Southcentral
and beginning to exit to the Interior. This is producing some
showers inland and steady rain along the coast (mainly from Valdez
to Cordova). Southeasterly gap winds have weakened from their
peak, but persist for Turnagain Arm into Anchorage, the Knik River
Valley into Palmer, and along the Copper River. While the day
started out cloudy, breaks of sun are developing behind the short-
wave this afternoon.

The aforementioned north Pacific short-wave and surface low will
lift northward into the Gulf tonight. The short-wave will amplify
and become negatively tilted, with the strongest portion of the
trough crossing Prince William Sound and the Copper River Basin on
Wednesday. Have increased rainfall totals, with an inch or more
likely for Prince William Sound communities and around a quarter
of an inch for much of the Copper Valley. Models are in much
better agreement on spreading light rain north and west to the
western Kenai, Anchorage, and Mat-Su by early Wednesday morning.
Thus, have adjusted the latest forecast to indicate the likelihood
of light rain Wednesday morning. The main wind impact will be the
development of a barrier jet along the north Gulf coast ahead of
the surface low on Wednesday. Gale force winds are likely from
south of Cordova eastward to Cape Suckling. The upper short-wave
will exit quickly northward late Wednesday. Cooler air aloft
behind the trough combined with some breaks of sun will trigger
a few afternoon/evening showers.

There will be very little break before the new Bering storm begins
to affect Kodiak, the Gulf waters, and Southcentral. A leading
frontal system will cross the western Gulf Thursday while a series
of generally weak upper level short-waves stream northward across
Southcentral. There will be a big difference in the mean flow of
this storm system, with much deeper south to south-west flow as
you head up in the atmosphere. There will still be southeasterly
gap winds at the surface, but these winds will be much shallower
and downslope flow will be much weaker. As a result, expect much
more widespread rain and rain showers with this storm Thursday
through Friday - including the western Kenai, Anchorage, and the
Matanuska Valley. With weaker short-waves, rainfall along coastal
areas will be somewhat lighter than it has been in recent storms.
The Copper Valley will be notably drier than the rest of
Southcentral under this flow. Temperatures will remain below
normal under mostly cloudy skies.

-SEB

&&


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

The deep upper-level trough and vertically stacked low over the
Bering continues to be the dominant weather feature and driver of
the overall weather pattern for much of the region. Early this
afternoon, isolated thunderstorms will be possible for northern
Southwest Alaska, from Bethel to Aniak and east. By this evening,
a shortwave pushing inland from the eastern Bering Sea will bring
a round of rainfall to the Kuskokwim Delta lasting through
tonight.

Beginning tonight, a new low pressure system, originating from the
northern Pacific will approach the western Aleutians, pushing a
swath of rainfall and gusty southeasterly winds from Adak to
Shemya early this evening. The low will continue to progress
northeastward, with the low center moving over Adak by Wednesday
afternoon, and its eastern leading front moving over Unalaska and
the Pribilofs. As its front tracks east, expect strong southerly
winds along the warm front, with the potential for westerly storm-
force gusts wrapping underneath the low, south of the Chain. The
front will then reach the Southwest coast by Wednesday night with
the front and parent low continuing to track northeast and
weakening through Thursday.

-CL

&&

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

Broad upper level troughing over the Bering Sea and Gulf looks to
continue to remain in place through the long term. Several
shortwaves rotating around the upper 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 into early next week.

Models are in good agreement to begin the long term period with
widespread showers across the southern Mainland as a shortwave
lifts north out of the Gulf. Farther south, a more potent
shortwave and surface low tracks across the southern Gulf with
most of its moisture and energy directed towards the Panhandle. By
early next week, the upper low over the Bering Sea weakens in
favor of a new, stronger low lifting north out of the North
Pacific towards the Aleutians. Some uncertainty remains on the
speed and exact track the deepening surface low takes as it
approaches the Aleutian Chain, but all guidance eventually ends up
tracking this system into the southeastern Bering Sea by late in
the period. Gusty winds accompanied by light to moderate rainfall
can be expected along the Aleutians and Alaska Peninsula before
pushing into the Gulf, with the heaviest precipitation expected
along the southern AKPen and immediate Gulf coast.

&&


.AVIATION...

PANC...VFR conditions will persist. The gusty southeasterly winds
are expected to diminish late this evening and then become light
from the north after midnight. While south-southeast winds develop
again Wednesday afternoon, they should not be nearly as strong as
the past two days. Light rain is expected to develop late tonight
and persist on-and-off into Wednesday afternoon.

&&


$$

307
FXAK69 PAFG 192349
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
349 PM 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 through
the week. Additionally, southerly flow will allow for warm, dry,
and windy conditions to persist through the middle portions of the
week, with brief chances for precipitation Wednesday night.
Southerly flow across the Alaska Range may cause wind gusts up to
55 mph in Isabel and Windy Pass.

&&

.KEY WEATHER MESSAGES...

Central and Eastern Interior...
- Gusty southerly winds are expected through the Alaska Range
passes today. Wind gusts through Isabel and Windy Pass are
expected to be up to 55 mph and 50 mph respectively. A Wind
advisory continues for Isabel Pass and Delta Junction through 1
AM tonight.

- Mostly dry conditions expected across the Interior this evening
with an increased chance of precipitation on Wednesday. A Red
Flag Warning continues for Delta Junction through 10 PM tonight.

- 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 to continue across the West Coast
through with an upper-level shortwave passage. Thunderstorm
chances continue for portions of the Western Interior.

- Showery conditions are expected along the Lower Yukon and Yukon
Delta regions throughout the week. Heavier showers are expected
tonight and Thursday, with light showers Wednesday. 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..
- Dirunal showers along the southern portion of the Brooks Range
are expected to continue through the week. Little to no
precipitation is expected for 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 evening, an ice jam 10 miles downstream of
Russian Mission remains in place mostly unchanged. 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 both Grayling and Holy
Cross. Flood warnings remain in effect.

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. The River Watch Team flew over
the ice jam Monday afternoon and reported that it consisted of about
1 mile of in place sheet ice at river mile 190 and extends upriver
45 miles with lots of rotten sheets and chunk ice. The head of the
jam looked rotten and may release soon.

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..

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

529
FXAK67 PAJK 192347
AFDAJK

Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
347 PM AKDT Tue May 19 2026

.SYNOPSIS...

Key Messages:


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

- Showers over the panhandle on Thursday, then another front
weakening and falling apart Friday.

- Quick look at the holiday weekend is, it is becoming more likely
that a potentially stronger Summer system to move to the
panhandle Sunday.


&&

.SHORT TERM...The active (by spring standards) pattern looks set
to continue through the duration of the period, as a series of
troughs and ridges continue to move up along the eastern flank of
a Rossby wave over the Pacific. A ridge moving over the southern
panhandle will bring drier weather through late Tuesday night for
areas south of Frederick Sound. The northern half of SE AK will
see lingering showers as moisture rotates in along the ridge axis,
further fueled by the remnants of a shortwave trough which will
move in through Tuesday evening.

On Wednesday, a far better developed system moves into the Gulf,
deepening as it moves toward Anchorage. The low will throw a gale
force front into the panhandle, which is progged to arrive Wednesday
morning across the Outer Coast and by Wednesday afternoon for the
rest of the area. This front will bring with it periods of
widespread moderate rain and windy conditions. Given the presence of
saturation across the atmospheric column, most of SE AK will see a
total of ~1 to 2 inches of rain. Given the system`s trajectory,the
NE Gulf Coast favored for the greater totals. The far southern
panhandle will be the exception, as they could receive lower totals
of ~0.5 to 1 inch as the bulk of the initial system moves north,
although a trailing cold front moving through Wednesday night will
bring some additional rainfall to this area. Flooding concerns are
not expected, as snow levels will remain on the lower side for this
time of year, and so do not expect much augmentation of the streams
from mountain runoff, alongside the rain itself. Some snow may mix
in with rain during the overnight hours - especially Thursday night -
at White Pass, but do not expect any significant accumulations.
Gusty winds will also be widespread, with gusts of 30 to 40 mph on
Wednesday across much of central and northern SE AK, with gusts
of 20 to 30 mph for the southern panhandle.

The system will depart on Thursday, with another ridge moving across
the panhandle. Similar to the previous ridge, the best chances of
some lingering rain showers will be for the northern half of the
area and the inner coastal mountains, while the south will be mostly
on the drier side by late Thursday afternoon. Temperatures will
trend toward the cooler side, with low temperatures getting down
into the low 40s or even upper 30s.

.LONG TERM.../ Friday to Tuesday / A front sweeps the western gulf
Thursday evening and to the eastern Gulf of Alaska Thursday night
and Friday. Yakutat should see good rain rates Thursday night and
early. 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 have
started to agree on a system to impact primarily the southern
panhandle after moving in from 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 stronger, 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... Other than some brief CIGS between 1500-2500 ft
dropping conditions to MVFR, on shore flow is bringing generally VFR
conditions across the area today.

Late tonight into Wednesday morning, a front will bring rain chances
and strong winds to the Panhandle. LLWS is expected begin for
Yakutat around 08Z with 30 kts and increasing to 45kts around 15Z.
All locations will see an increase in wind speed, and this front
will also increase precipitation chances from west to east across
the Panhandle. Expect conditions to deteriorate to IFR for the
Southern Panhandle with CIGS AoA 700 ft and VSBYS 3-4 SM.

Tonight, clearing is expected to lead to fog development for areas
south of Fredrick Sound. The fog will bring those locations down to
IFR conditions, and will likely stay through the rainfall arriving
with the front around the end of the TAF period. Based on satellite,
Klawock is experiencing the most clearing and the greatest chance
for fog. Although, brief improvement does look possible before the
rain arriving with the front.

&&

.MARINE...
Outside (Gulf and Coastal Waters):On this beautiful Southeast
day, winds and seas are in the relative calm before the gale,
with coastal buoys and ASCAT winds showing gentle to moderate
breezes out of the south; the exception is Cape St. Elias, seeing
ESE strong breezes. Riding underneath these winds was a
diminishing southwest swell, with buoy 84 showing an astonishingly
clear swell signal 12-14 seconds at 6 ft earlier today. The story
will begin to change today as a gale force front impacts the
region over the next 48 hours; currently this system is developing
near 48N 158W and moving northeast. As gales build along Cape St.
Elias Tuesday evening, winds will continue to increase along the
rest of our coast, reaching near-gale to gale force by Wednesday
morning. Confidence is high that we will see gales from the
Fairweather Grounds to the northern coast. The primary forecast
challenge for winds today remains in how far south gale force
winds will move. Mariners north of Cape Decision operating along
the coast should plan for a few hours of gale force winds as the
front moves over, sometime near 2pm to 5pm local time Wednesday.
Fresh seas out of the southeast will also begin to dominate, with
southwest swell being masked and significant heights reaching 12
to 15 ft by Wednesday afternoon. Expect winds and seas to diminish
Thursday afternoon before westerly swell of 7 to 9 ft at 13 to 15
seconds begins to impact our coast by the weekend.

Inside (Inner Channels):
Winds are in their calm period this Tuesday afternoon. Expect
winds to build out of the south early Wednesday morning, with
sustained winds reaching peak intensity of strong breezes to near-
gales through many inner channels Wednesday. Current model
consensus is the strongest winds will occur sometime in the
afternoon to evening, depending on where you are in Southeast,
with the highest winds from Icy Strait/Taku south to Sumner.
However, the simple message is it will be a wet and windy
Wednesday, with subpar conditions for folks wishing to move around
in small recreational vessels. Conditions will improve greatly by
Thursday afternoon.

One word of caution is the northern arms of Glacier Bay could be
particularly strong Wednesday night into Thursday morning as an
occluding front makes landfall along the northern coast. Expect
strong southeast winds to quickly becoming south; this wind shift
could surprise some folks. Mariners near any large inlets in the
upper arms of Glacier Bay like Reid Inlet should be ready for
gale force gusts coming off the ice field. These gusts could be
stronger.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Wind Advisory from 1 PM to 7 PM AKDT Wednesday for AKZ323-325-
327.
MARINE...Gale Warning for PKZ642>644-651-652-662>664-671-672.
Small Craft Advisory for PKZ011-013-021-022-031>036-053-641-661.

&&

$$

SHORT TERM...GFS
LONG TERM...Bezenek
AVIATION...Musall
MARINE...AP

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