Graphical Hydro Meteorological Discussion

803
FXAK68 PAFC 201349
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
549 AM AKDT Mon Apr 20 2026

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

A series of shortwaves will propagate through Southcentral Alaska
today into tonight in the southwesterly flow aloft. The first one
is in the northeastern Copper River Basin and heading into the
Yukon. This wave helped bring in the advisory-level snowfall to
the southern slopes of the Alaska Range. With it moving out of the
area that advisory has been canceled.

The second wave can be seen on satellite imagery early this
morning over northern Cook Inlet. This is a weak wave and is
mainly just bringing some mid to high level clouds with snow
showers relegated to the Talkeetna and Chugach Mountains.

The third shortwave is entering southern Cook Inlet early this
morning and is a much stronger wave. This is the shortwave that
is expected to bring showers to the Kenai Peninsula by late
morning and to Anchorage and the Mat-Su this afternoon. With the
southerly surface winds persisting (though not as strong as
yesterday), the precipitation type should mainly be rain. However,
there is a chance for some snow to mix in this morning as well as
in heavier showers. There is also the potential for small hail in
these showers due to the low freezing level. The Anchorage ROAB
showed a freezing level of 1100 ft at 3 AM, but this is expected
to rise as the day progresses.

After this third shortwave moves through, the flow aloft will
shift more westerly for Tuesday which should bring a few breaks
in the clouds and less shower activity. However this will be short
lived as an atmospheric river will bring a return to wet and
windy conditions.

&&


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

Rain and snow showers will persist today across the southwestern
mainland as a series of upper-level disturbances moves in from the
Bering Sea. The expectation is for continued showery
precipitation across the area with westerly upslope enhancement
along the Western Alaska Range and Aleutian Range. This activity
will taper off through Tuesday morning as an upper-level shortwave
ridge begins building into the southwest mainland by then.
Despite the ridge moving in, expect another overcast day across
Southwest for Tuesday.

Attention then quickly turns to the next significant Bering Sea
system which is currently gathering strength just southeast of
Shemya this morning. This system will deepen further tonight and
Tuesday as it wraps in more cold air from Russia and remains
nearly stationary between Adak and Amchitka through early
Wednesday morning. As the system spins between Amchitka and Adak,
multiple frontal systems will be sent northward and eastward. The
first of which will be today through tonight with Adak and the
Pribilofs seeing light rain with the gustiest winds remaining
confined to Adak.

The second and more widespread frontal push of moisture will
arrive with moderate to heavy rain Tuesday morning to Adak and
Atka and will arrive to the Pribilofs and Nikolski/Unalaska/Akutan
by late Tuesday morning to early Tuesday afternoon. By Tuesday
afternoon, the storm strengthens to storm-force on the northern
periphery of the system just west of the Pribilofs. Heavy rain
moves to False Pass, King Cove, Cold Bay, and Sand Point by
Tuesday evening. Moisture also makes its presence known across
mainland Southwest Alaska also by Tuesday evening. The Kuskokwim
Delta and Nunivak Island could see a period of snow at the onset
of precipitation Tuesday evening before turning to rain overnight
Tuesday as warm air and southerly flow advance northward. Heavy
rain will not stay over the Alaska Peninsula too long as the
moisture corridor shifts east to Kodiak Island by Wednesday
morning with the Interior Kuskokwim Delta, Kuskokwim Valley, and
Bristol Bay continuing to see light to moderate rain at times
Wednesday morning through Wednesday evening.

The storm slowly pulls northeastward to the central Bering near
the Pribilof Islands by Thursday morning. Additional cold air gets
pulled southward into the western Bering from Russia on the
backside of the storm. Rain/snow showers are a good bet for Shemya
from Wednesday afternoon into Thursday morning as the unstable
airmass moves overhead. The Pribilofs will contend with an
additional round of rain or rain/snow mix Wednesday evening into
Thursday morning as showery conditions also persist across
mainland Southwest for that time period as well.

&&


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

Unsettled conditions will likely persist across much of Alaska
through the upcoming week. A low over the southern Bering Sea will
move toward Nunivak Island by Thursday morning. South to
southwesterly flow with gusts up to 40 mph will move across
Kuskokwim Bay/Delta area. Concerns for coastal impacts is low due
to shorefast ice and some added protection from the expansive ice
flow over the eastern Bering Sea.

The accompanied front from the Bering low will move into the
western Gulf of Alaska, drawing with it a relatively deeper surge
of moisture. Coastal areas in the northern Gulf and Kodiak Island
and higher elevations of the Alaska Range will likely see the most
precipitation. Away from the coast, expect several days of mixed
precipitation to continue, including rain at lower elevations and
snow at higher elevations. Southeasterly flow will allow some
downsloping to the west of the Chugach and Kenai Mountains.

Model agreement decreases significantly late in the week, though
some semblance of a low continues to place a low in the southern
Bering Sea with southerly flow persisting into Southcentral. It is
probable that our overall pattern will not deviate much from what
we are already seeing, however, the details should become clear
with the timing of these key wind and precipitation features as we
approach the mid to late week timeframe.


&&



.AVIATION...

PANC...Gusty southerly winds will gradually diminish through the
day today, with peak gusts decreasing from 30 to 20 kts through
around 08Z. VFR conditions will likely prevail today, with only a
slight chance of briefly dipping into MVFR conditions with
passing showers this afternoon. Southerly winds will continue to
diminish, remaining light through tomorrow morning.

&&


$$

568
FXAK69 PAFG 201437
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
637 AM AKDT Mon Apr 20 2026

.SYNOPSIS...
The remnants of a low are expected to make their way across the
state, bringing scattered snow showers to much of the Interior and
North Slope through Tuesday night. This low is also expected to
create a strong gradient on the West Coast which will support
gusty northerly flow and periodical blowing snow. A brief break in
precipitation and wind is expected across Northern Alaska. Following
this short stretch of quieter weather, another low is expected to
move into the southern Bering Sea early Wednesday morning. Mixed
precipitation and freezing rain will be likely over the YK Delta
with scattered snow and rain showers expected to persist for much
of the state through the upcoming weekend. Strong easterly/
northeasterly winds are anticipated to return on the West Coast,
with strong gusts at high Interior elevations as well. The
associated warm front will support warmer temperatures later in
the week, with many locations seeing high temperatures above
freezing.

&&

.KEY WEATHER MESSAGES...
Central and Eastern Interior...

- Scattered light to moderate snow showers will continue across
the Interior and Alaska Range early this week, tapering off by
midweek ahead of another system moving in mid-to-late week.

- Additional snowfall amounts through Tuesday are expected to be
around 1-4" in the Eastern Interior valleys and 3-8" in the
mountains and valleys west of the Dalton and Parks Highways.
Locally higher totals are expected in the Alaska Range, where
around 8-12" of snow is expected for higher elevations of the
Parks and Richardson Highways with locally higher totals above
pass level.

- Winter Weather Advisories and Winter Storm Warnings remain in
place for the Central Interior and Alaska Range through Monday.

- Looking ahead, high confidence supports a strong low pressure
system moving north through the Bering Sea mid-to-late week
which will eject a series of fronts. This system will bring in
mixed precipitation chances, gusty winds (particularly through
Alaska Range Passes), and the warmest temperatures so far this
year.

West Coast and Western Interior...

- Scattered light to moderate rain and snow showers will continue
across the Western Interior and West Coast south of and
including the Seward Peninsula. These showers will taper off
today into tomorrow west to east ahead of another system moving
in mid- to- late week.

- Additional snowfall amounts through Tuesday will range from
around 1-4" along the southern West Coast to around 4-8" in the
Western Interior. A rain/snow mix will remain possible farther
south.

- Strong winds continue through the Bering Strait to St. Lawrence
Island, with wind gusts up to 50 mph leading to areas of blowing
snow.

- Winter Weather Advisories and Winter Storm Warnings remain in
place for portions of the Western Interior and Interior Norton
Sound, in addition to the Bering Strait Coast through today.

- Looking ahead, high confidence supports a strong low pressure
system moving north through the Bering Sea mid-to-late week
which will eject a series of fronts. This system will bring in
mixed widespread precipitation chances, gusty winds, and the
warmest temperatures so far this year.

North Slope and Brooks Range..

- Scattered light snow showers will continue to lift north into
the Central/Eastern Brooks Range and Southern Arctic Plains
through today and tomorrow. Snow accumulations around 1-3" are
expected in this region. Snow chances will subside midweek.

- Gusty winds continue for the Western Brooks Range/Arctic Coast,
leading to areas of blowing snow and reduced visibility at
times. Breezy winds will expand east across the North Slope and
Brooks Range today into tomorrow, strongest along the Arctic
Coast.

- Looking ahead, high confidence supports a strong low pressure
system moving north through the Bering Sea mid-to-late week
which will eject a series of fronts. This system will bring in
mixed widespread snowfall chances (lower chances for mixed
precipitation), gusty winds, and the warmest temperatures so far
this year.

- This week will see a significant warmup from lows in the double
digits below zero temperatures Monday morning to 20s/30s above
zero for highs later in the week.

&&

.FORECAST ANALYSIS AND DISCUSSION...
Today through Wednesday Night.

An upper level low is expected to linger over much of Northern
Alaska through Tuesday afternoon. The presence of this low will
allow for cold and dry conditions and strong winds to persist on
the North Slope. Precipitation-wise, snow chances are likely to
continue for most of the Interior through late Tuesday night as
the low continues to transport moisture into the area. Around the
early Tuesday morning time frame, moisture becomes wrapped in the low
center`s circulation as this system moves across Northern Alaska.
As a result, rain and snow showers are likely for the North Slope
through Tuesday and early Wednesday. This current system is also
expected to support strong northerly winds through the Bering
Strait and over most of the West Coast. Southerly gap winds
through the Alaska Range passes are also expected to remain
elevated for the earlier portion of this morning.

The outer edge of an upper level ridge begins to move into
Southern Alaska Tuesday morning. A tight gradient between the low
and the ridge is expected to support strong westerly winds in the
Interior with the strongest gusts at the highest elevations.
An extratropical cyclone begins to push the ridge to the
northeast Wednesday morning. The progression of this system`s
triple point is expected to bring strong easterly/northeasterly
winds to the West Coast and will gradually build a strong south to
north gradient in the Gulf. This pattern will support strong gap
winds through the Alaska Range passes and significant downsloping
into the Interior. As a result, Interior high temperatures are
expected to increase from the mid 30s/low 40s above to the low to
mid 50s by Thursday. The associated warm front with this system is
expected to assist with moisture transport across the state.
Mixed precipitation is likely to start over the YK Delta area
Wednesday morning with brief chances for freezing rain. Scattered
snow and rain showers are possible for the Interior through
Thursday night. More scattered precipitation chances are expected
throughout the week as the cyclone gradually breaks apart and
dissipates.

&&

.EXTENDED FORECAST DAYS 4-7...
Thursday through next Sunday.

An extratropical cyclone will approach Southwest Alaska around the
Wednesday morning time frame. Scattered mixed precipitation is
likely for the Yukon-Kuskokwim Delta region through the weekend,
with scattered rain/snow chances for the Interior and Brooks Range
likely as well. The orientation of this system with the upper
level high is expected to create a tight south to north gradient,
significantly warming temperatures across the state with high
temperatures above freezing for many locations. Strong
easterly/northeasterly winds are expected for high elevations in
the Interior as well as a large portion of the West Coast through
Friday night.

Coastal Hazard Potential Days 3 and 4...None


&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Storm Warning for AKZ829-830-850-852.
Winter Weather Advisory for AKZ820-821-832-834-838>846-848.
Winter Storm Warning for AKZ824.
PK...Brisk Wind Advisory for PKZ801.
Brisk Wind Advisory for PKZ802.
Brisk Wind Advisory for PKZ805-806-810-850-853.
Brisk Wind Advisory for PKZ807-856.
Brisk Wind Advisory for PKZ808-809.
Brisk Wind Advisory for PKZ811.
Heavy Freezing Spray Warning for PKZ816.
Brisk Wind Advisory for PKZ852.
Brisk Wind Advisory for PKZ857.
&&

$$

Srinivasan

293
FXAK67 PAJK 201945 CCA
AFDAJK

Southeast Alaska Forecast Discussion...UPDATED
National Weather Service Juneau AK
1145 AM AKDT Mon Apr 20 2026

.SHORT TERM...A front a day is in order for the northern half of
the panhandle, with an exiting shortwave trough this morning, and
another shortwave racing along the NE gulf coast for this evening.
Unfortunately for those in the north, not expecting to bring back
PoPs or cloud cover substantially today, with westerly facing
mountains expected to stay somewhat wet and definitely cloudy for
most of the day. Furthermore, low pressure in Canada combined with
ridging in the southern panhandle looks to keep stronger winds for
the Skagway area. Still expecting to have these winds drop below
wind advisory criteria by 7 AM this morning; however, these winds
will likely stay around 35 mph until this evening. For the southern
panhandle, divergent flow and surface ridging looks to keep much of
the moisture and rainfall away. Looking to see these areas slowly
clear out over the course of the day.

.LONG TERM.../Wednesday through Saturday/
The ridge over the Gulf of Alaska will move east and build over the
panhandle through the day Wednesday and into Thursday. This ridge
will be associated with low precipitation totals for most of the
area. With the exception being northwest of Cross Sound, where
showery conditions will remain in place. A second wave of moisture
is expected to reach the northern gulf coast Friday morning. This
will bring more persistent precipitation, however impacts will be
minimal as there is a 20-30% chance that Yakutat will see more than
0.3 inches of rain.

Impactful winds are not expected through the weekend, but the
diurnal cycle could cause breezy conditions in the inner channels.
However, when skies are clear and winds lighten, there remains the
possibility of isolated fog in the overnight hours, particularly the
southern half of the panhandle. Temperatures will gradually increase
throughout the week as the ridge moves over the panhandle bringing
upwards of 60 degrees in Ketchikan and POW Island. Northern
locations will see high 40s and low 50s by the weekend.

&&

.AVIATION.../Thru 18z Tuesday/ Variable conditions across the region
today with scattered showers across the north and clouds assoc. with
a decaying front across the south.

Ceilings are expected to improve to VFR by afternoon for most areas
with largest sunny breaks over the inner channels due to WNW flow
aloft. Tonight another weak disturbance moves over the top of our
ridge from the W. This will bring more light rain and ceilings down
to MVFR starting over PAYA tonight and over the northern panhandle
again into Tuesday morning.

Gusty south winds to 30kt continue in northern Lynn and
Skagway/White Pass areas. That is expected to continue into the
Monday evening at least before diminishing. Otherwise lighter winds
15 kt or less for most other areas of the panhandle through Tuesday
with afternoon sea breezes.

&&

.MARINE...
Outer Waters: Fresh to strong breeze westerlies will prevail into
Tuesday evening. Westerly swell looks to slowly build as well,
particularly in waters to the south of the 57 degrees latitude line.
Wave heights associated with this swell looks to build from 7-8 ft
at 8 seconds to 10-12 ft at 14 seconds by this evening.

Inside Waters: Relatively stagnant pattern, with the Icy Strait
corridor including Cross Sound and Lynn Canal looks to remain
elevated through this evening, with a tight southerly pressure
gradient driving much of the flow. Increasing northwesterlies in the
southern panhandle to a moderate breeze is expected to keep any fog
development away, even with moist conditions and ridging aloft.

&&

.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Wind Advisory until 7 AM AKDT this morning for AKZ318.
MARINE...Small Craft Advisory for PKZ012-013-021-022-053-641>644-651-
652- 661>664-671-672.

&&

$$

SHORT TERM...NC
LONG TERM...AGP
AVIATION...FERRIN
MARINE...NC

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