FXAK68 PAFC 240111

AFDAFC



Southcentral and Southwest Alaska Forecast Discussion

National Weather Service Anchorage AK

511 PM AKDT Thu Apr 23 2026



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

through Sunday)...



Key Points:



* Continued unseasonably wet and windy weather through Friday 

  night.



* The wettest weather will be the eastern Kenai Peninsula, Prince

  William Sound, and Susitna Valley. There has been a break in

  rain for many of these areas this afternoon, but the next round

  of heavier rain will arrive by this evening. 



* Additional rainfall through Saturday morning: 2 to 5" along the

  Gulf and Prince William Sound coastlines (including Seward,

  Whittier, Valdez and Cordova) 0.50 to 1" over eastern interior

  Kenai Peninsula; 1 to 2" in the western Susitna Valley; and

  lighter amounts elsewhere. 



* A Flood Watch remains in effect for the Susitna Valley from 9pm

  this evening through Saturday morning. Rain and snowmelt

  combined with still frozen surfaces could make it hard for all

  of the water to find a place to properly drain. As a result,

  there could be minor flooding of low-lying roads and properties.



* Strong and gusty southeasterly gap winds will persist through at

  least Friday afternoon. Locations that will see some of the

  strongest winds include Turnagain Arm, Anchorage Hillside, south

  to west Anchorage, Palmer and the Knik River Valley, and

  Glennallen and the Copper River. 



A high amplitude pattern remains firmly entrenched over Alaska, 

with a trough in the Bering Sea/North Pacific and a ridge 

extending from the northeast Pacific to the Al-Can border. Deep

and moist southerly flow is noted in water vapor with a moisture

plume streaming northward from around 40N latitude up to the

western Gulf. A series of vigorous shortwaves can also be seen in

satellite imagery, with the strongest approaching Kodiak Island

and the western Gulf this afternoon. At the surface, a weak

frontal wave is tracking northward up a stationary front which

sits beneath the upper level moisture plume. As these features

continue northward, stronger winds and steady rain are spreading

across Kodiak and the western Gulf. Meanwhile, there is a brief

break in significant rainfall (and mountain snow) over

Southcentral, with just some localized light precipitation in

upslope areas along the south side of mountain ranges. Otherwise,

it is cloudy with gusty southeast winds (especially through the 

typical coastal gaps) and temperatures in the 40s to around 50. 



While the expected weather for the next couple days is generally

on track, there have been some shifts in model guidance with

depiction of individual short-waves which will affect the timing

of heaviest precipitation and strongest winds. The short-wave now

approaching the western Gulf now looks like the strongest of 

short-waves with the best moisture transport aloft. It will 

amplify just a bit as it continues northward across the western 

half of Southcentral tonight. The heaviest precipitation will be 

across the southeastern Kenai Peninsula and northern to western 

Susitna Valley from approximately 9pm this evening through 6am 

Friday. Southeasterly winds will ramp up once again (ahead of the 

short-wave), with the strongest winds along Turnagain Arm and 

affecting the Anchorage Hillside. Winds look a bit stronger than 

last night, with a few gusts of 60 mph or higher likely for upper 

Potter Marsh and the upper Hillside of Anchorage. With the ground

still largely frozen and trees yet to leaf out, do not expect any

significant impacts due to these winds. 



Another short-wave will cross nearly the same area Friday afternoon

through Friday night. Model guidance has trended toward a weaker,

less amplified short-wave. As a result, winds and precipitation 

rates with this short-wave look less impressive and the forecast 

has been updated to reflect this. 



The upper level flow will shift behind this short-wave on Saturday

as a new storm system moves into the Bering Sea, bringing an end 

(temporarily) to the deep southerly flow and moisture transport.

One final short-wave will cross through Southcentral during the

day Saturday, but precipitation with it will be quite light. A

short-wave ridge will then briefly move through Saturday night 

into Sunday morning, with the frontal system from the Bering storm

following closely behind. The upper level flow on Sunday will 

look very similar to what is in place today. Thus, unseasonably 

wet and windy weather will return late in the weekend and into 

the new work week. 



-SEB 



&&





.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 

1 through 3: Tonight through Sunday)...



Key messages:



- A low over the northern Bering Sea will steadily weaken through

  Friday night.



- An unseasonably strong low will rapidly deepen as it approaches

  the central portions of the Aleutians on Saturday.



- Very strong winds could impact much of the Aleutian Chain as the

  low crosses into the southern Bering Sea on Sunday. Widespread

  Gale to Storm Force winds could impact much of the marine

  outlook area this weekend.



Discussion:

  

A broad region of cyclonic flow now extends across much of the

Bering Sea and Aleutians, with several embedded shortwave troughs

rotating around the larger area of low pressure. Two of such

disturbances are moving north into Southwest within a belt of 

southerly flow, ushering a few bands of light rain north across 

the region. Much of Southwest is still seeing rather blustery 

conditions as well, with gusty southeast winds persisting around 

the eastern fringes of a weakening surface low moving over Saint 

Matthew Island. Things have quieted down for now across most of 

the Aleutian Chain, where light west winds are prevailing along 

with occasional rain/snow showers drifting past.



From tonight through Friday night, little change in the general

pattern is expected as the low moving over the northern Bering Sea

steadily weakens and as multiple shortwave troughs continue to

move northeast along the AKPen and over Southwest. Multiple rounds

of mostly rain will continue to affect much of the AKPen, Bristol

Bay and Kuskokwim Delta as these upper waves move across.

Generally calm conditions will continue across the Pribilofs and

Aleutians, but this will change rather abruptly over the upcoming

weekend.



On Saturday morning, a North Pacific low will phase strongly with

a potent trough approaching from the west and rapidly deepen into

a 950-960 mb Hurricane Force low as it approaches Adak and Atka by

Saturday afternoon. Model agreement for this system continues to

improve, and it now looks likely that the low center will cross

over into the southern Bering Sea near or just west of Adak by

Saturday evening. A sting jet of intense winds will develop to the

south of the low center, and this corridor of strong winds will

progress north into the central/eastern parts of the Aleutian

Chain by early Sunday morning. Even though the low will reach peak

intensity prior to moving into the Bering Sea, this corridor of

winds will still be quite intense. Storm Force sustained winds

with Hurricane Force gusts will overspread much of the marine

waters surrounding the eastern half of the Aleutians, with

potential for wind gusts of 60 to 70 mph or stronger to impact

Adak, Atka, Nikolski and Unalaska as the low shifts north late

Saturday night into Sunday. Seas as high as 40 ft will move in

tandem with the corridor of strongest winds south of the 

Aleutians between Adak and Nikolski Saturday night into Sunday 

morning.



Farther north, the low's leading front will push across the

Pribilofs on Saturday night, spreading precipitation initially in

the form of snow across the islands along with southeast winds

gusting to around 60 mph. Temperatures will likely be hovering at

or just above freezing by this point, so this will limit potential

for blowing snow. Snow will transition to rain as temperatures

continue to warm on Sunday morning, while gusty winds to the east

of the low center persist. The front will reach the Southwest 

Coast Sunday morning, with a similar progression from wet snow to 

rain expected through the day on Sunday as gusty southeast winds 

also spread across Southwest along and ahead of the incoming 

front. Stay tuned for more details as we continue to monitor this 

unseasonably strong storm system through this weekend.



-AS



&&





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

Thursday)...



Unsettled weather is expected to persist across much of Alaska

into early next week as a North Pacific low moves into the 

southern Bering. The low will then track northward, passing 

northwest of the Pribilof islands by Monday while gradually 

weakening and occluding. Storm force winds are possible across 

portions of the central Aleutians Sunday into Monday, with 

widespread gale-force winds otherwise expected across the 

Aleutians, much of the Bering and Bristol Bay through Tuesday. 

Coastal impacts remain limited at this time due to the presence of

shorefast ice and an extensive ice pack over the eastern Bering. 



A frontal system associated with this low will move into the

Alaska Peninsula and Southwest Alaska Sunday morning, reaching the

western Gulf and Kodiak Island by Sunday afternoon and then 

progressing into Southcentral Alaska Sunday night. This system 

will bring a steady stream of moisture into southern Alaska, 

resulting in widespread precipitation as the front advances. The 

heaviest precipitation is expected across Kodiak Island, along the

northern Gulf Coast, and across higher elevations of the Alaska 

Range due to upslope enhancement from southeasterly flow. In 

contrast, downsloping effects are likely to limit precipitation 

across portions of the western Chugach and Kenai Mountains, as 

well as along the Bering side of the Alaska Peninsula.



As the primary low weakens and occludes over the northern Bering,

additional shortwave disturbances are expected to rotate around

the parent low and move northward into Alaska. Model guidance is

in general agreement on a shortwave moving into Southcentral

Alaska Monday night into Tuesday, which will support another

period of enhanced precipitation, particularly along the northern

Gulf Coast and Kodiak Island where southeasterly flow persists. 



Beyond Tuesday, model solutions begin to diverge with respect to

the timing and placement of additional shortwaves. Some guidance

brings additional energy into Southwest Alaska Tuesday into

Wednesday, while other solutions delay impacts into Southcentral

Alaska until midweek. Confidence in the details decreases during

this period; however, the overall pattern continues to support a

persistent feed of moisture into southern Alaska, especially

across Southcentral.  



LM



&&



 

.AVIATION...





PANC... Southeasterly Turnagain Arm winds will continue to impact

the terminal this evening and overnight with strongest gusts of 

between 35 to 45 kts expected from about 7Z to 12Z as a front 

pushes through the area and winds bend more towards the terminal.

However, lighter northerly winds may precede the front as the

stronger winds stay over the Arm towards Fire Island allowing for

some LLWS concerns this evening. VFR conditions are expected to 

persist, though any passing showers may drop ceilings below 5,000 

ft AGL and briefly drop visibility to MVFR. Downslope flow will 

continue to keep most showers out of Anchorage, though chances 

will increase overnight.





&&





$$