NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

PKZ752 Castle Cape To Cape Tolstoi Out To 15 Nm- 359 Am Akst Sat Dec 9 2023
.small craft advisory Sunday...
Today..W wind 15 kt. Seas 4 ft.
Tonight..N wind 20 kt. Seas 6 ft.
Sun and Sun night..NW wind 30 kt. Seas 10 ft.
Mon through Wed..NW wind 30 kt. Seas 8 ft.

FXAK68 PAFC 090153 AFDAFC

Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 453 PM AKST Fri Dec 8 2023

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

The main upper trough axis that swept through Southcentral from the southwest early this morning is now swinging up towards the northern Alaska Range. This has given way to a showery pattern across mainly the Gulf, with a much colder air mass and southwest flow aloft. Most of the snow showers are staying out over the Gulf for the time being, but they will likely soon begin to work back onshore later this evening into tonight.

Overall, the forecast confidence for Saturday morning onwards has unfortunately not improved much compared to 12 hours ago. Models are still struggling to lock in on the trajectory and progression of a weak shortwave trough moving into the Kenai Peninsula and Prince William Sound region from the southwest on Saturday while a small, weak low spins up just south of the Kenai Peninsula and shifts in the same direction through Saturday evening. This setup is not terribly unlike what we just saw come through in the past 24 hours, but will not feature much on the way of cold advection with the colder air mass already in place out ahead of this next feature. Scenarios for snowfall timing and amounts still vary considerably for Saturday, but the overall thinking is still for light snow to develop over the southern Kenai Peninsula late tomorrow morning, then spread northeast up into Kenai Peninsula later in the day, and finally move out towards Valdez and Cordova during the afternoon and evening as a deeper, west to east oriented upper trough lifts north into the southern Mainland.
Given the continued spread in even higher resolution guidance, will still with a general 0.5 to 2" for the Mat Valley, Anchorage and western Kenai Peninsula corridor, with higher amounts up to 6" out closer to Seward and Whittier through Saturday night.

Attention from there quickly shifts to what could become a fairly high impact system across at least parts of Southcentral starting on Sunday. On Sunday morning, a low pressure over the North Pacific will move up near Kodiak Island by Sunday morning as an upper ridge rapidly builds out ahead of it into the Gulf.
Widespread precipitation will spread from Kodiak Island up into the Gulf Coast as a warm front lifts north throughout the day, affecting mainly the coastal mountains as developing southeast low level flow carrying higher moisture north and west upslopes into higher terrain. Solutions for the track of this low have largely trended west, with it looking increasingly likely the surface low will track north somewhere along the western Alaska Range, potentially going right up the Cook Inlet through Monday morning as the supporting upper trough phases with the upper level low drifting over Bristol Bay. This more west track compared to what we've seen from earlier projections would favor much more cross-barrier flow setting up across the Kenai and Chugach range, limiting snowfall potential for the Mat Valley and Anchorage Bowl until the occluded front lifts through sometime on Monday. Strong gap winds through the Turnagain Arm, Thompson Pass and Matanuska Valley will also be a concern, potentially leading to issues with blowing snow between Sunday and Monday in these areas as well.

There is still a lot of room for details with this storm system to change, so please continue to monitor the forecast as we further dial in details over the next couple days.

-AS

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3: Today through Sunday)...

An upper trough persists over the Kuskokwim Delta through Saturday with one or more shortwaves to rotate through the trough and just offshore of the Kuskokwim coast. High pressure remains over the western Bering, while an eastward moving shortwave trough tracks south of the Aleutians before eventually wrapping northward into the Greater Bristol Bay area on Sunday. The Kuskokwim Delta trough will sag slightly southward with the passage of each shortwave today and tomorrow. A pattern change then begins to develop by Sunday as the trough phases with the wave lifting into Bristol Bay, forming a much more amplified trough over the AKPEN and Western Alaska Range over the latter half of Sunday.

For tonight, calmer conditions continue for the rest of Southwest Alaska. Scattered light snow will remain possible tonight and tomorrow while the presence of the upper trough lingers over Southwest Alaska. There is some uncertainty in regard to potential heavier snow amounts over the Greater Bristol Bay region on Sunday.
The NAM seems to be the most aggressive model with Iliamna accumulating 4 to 6 inches of snow through the weekend. Finally, the Kuskokwim Delta should experience a notable temperature drop over the next 36 hours. Current temperatures in the teens steadily decrease to near zero by Sunday morning as northerly flow opens up over the Kuskokwim Delta.

Elsewhere northerly flow and weak high pressure will persist in the Bering Sea. The only significant change will occur over the Western and Central Aleutians as a subfreezing air mass spills well south of the Aleutians through Monday.



.LONG TERM FORECAST (Days 4 through 7)
Tuesday through Friday

The weather pattern continues across the region through Friday.
Ridging over the Western Bering and Canadian Provinces brackets the reorienting longwave trough over Mainland Alaska. A number of energetic shortwaves continuing their trek along the Western edge of the trough bring uncertainty to the composite blend of models over the initial periods. The closed low center in the mid-trough weakens through the end of the forecast period, as it loops around the Southcentral coast. With colder air pouring in with the trough, most precipitation will be snow showers over Western Alaska and along most of the Alaska Peninsula and Aleutians. Along with the snow, gusty winds increase to gale force over the Eastern Bering, Alaska Peninsula and Eastern Aleutians, diminishing late Thursday. Further West, a well developed Kamchatka low extends a front over the Western Bering and Aleutians, with mixed rain and snow as well as gales along the front through Friday.

Over the Gulf of Alaska, transient lows and fronts from the North Pacific spool up a widespread multi-day precipitation event from the Alaska Peninsula to the Canadian Border. Coastal areas begin with locally heavy rainfall changing to snow further inland as the area spreads to the Alaska Range through the end of the week.
Gusty winds offshore increase to gale force for Thursday and Friday, with a gale barrier jet along the North Gulf Coast late Thursday, diminishing Friday.

Kutz

AVIATION

PANC...VFR conditions are expected through at least Saturday morning before the next system starts to approach. However, with mostly clear skies allowing for modest radiational cooling overnight, there is the potential for fog to develop in the vicinity of, or move into, the terminal after 12Z. If fog does develop, expect ceilings to drop to below 500ft and visibility to under 1SM.

toggle option: (graph/table)

Chiachi Island (east side)
Click for Map
Sat -- 05:09 AM AKST     3.72 feet Low Tide
Sat -- 06:08 AM AKST     Moonrise
Sat -- 09:54 AM AKST     Sunrise
Sat -- 11:16 AM AKST     7.92 feet High Tide
Sat -- 03:09 PM AKST     Moonset
Sat -- 05:03 PM AKST     Sunset
Sat -- 06:27 PM AKST     0.93 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Chiachi Island (east side), Alaska, Tide feet

Kupreanof Harbor
Click for Map
Sat -- 05:07 AM AKST     3.72 feet Low Tide
Sat -- 06:09 AM AKST     Moonrise
Sat -- 09:54 AM AKST     Sunrise
Sat -- 11:13 AM AKST     7.92 feet High Tide
Sat -- 03:10 PM AKST     Moonset
Sat -- 05:04 PM AKST     Sunset
Sat -- 06:25 PM AKST     0.93 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Kupreanof Harbor, Paul Island, Alaska, Tide feet

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Please run setup again to find your radar station. Click HERE.