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PKZ742 Cook Inlet Kalgin Island To Point Bede- 324 Am Akst Sat Dec 9 2023
.gale warning today and Sunday...
Today..N wind 35 kt diminishing to 20 kt in the afternoon. Seas 10 ft subsiding to 5 ft in the afternoon. Freezing spray. Snow showers.
Tonight..SW wind 10 kt becoming E after midnight. Seas 3 ft.
Sun..NE wind 45 kt. Seas 13 ft. Freezing spray. Snow.
Sun night..NE wind 50 kt. Seas 15 ft.
Mon through Tue..N wind 25 kt. Seas 6 ft.
Wed..NE wind 20 kt. Seas 5 ft.

PKZ700
No data

FXAK68 PAFC 091430 AFDAFC

Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 530 AM AKST Sat Dec 9 2023

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

Key Messages:

-A system will bring snowfall to the Kenai Peninsula into Anchorage and the Mat-Su Valley today. Heaviest snowfall will be focused along the coast, as well as the Seward Highway from Girdwood south to Seward, where 3 to 6 inches of snow is possible by this afternoon.

-Sunday through early next week: A series of low pressure systems will bring a nearly continuous stream of moisture into the Kenai and Chugach Mountains. Several feet of snowfall is likely for the mountains, including the higher elevation passes on the Seward and Richardson Highways.

Discussion:

An active winter weather pattern is well underway for southcentral Alaska. GOES water vapor imagery shows three items of interest: 1) A deep upper-level low spinning across southwest AK. 2) A shortwave trough rotating about the aforementioned low that is projected to lift across the Kenai Peninsula and the rest of southcentral Alaska later today. 3) A developing low that's currently (as of 430am Saturday) a couple hundred miles south of the central Aleutians that is expected to phase with the aforementioned SW AK low and then move into southcentral Alaska Sunday into early next week.

As of 430am, radar imagery shows snow has already begun to spread across much of the Kenai Peninsula, with an area of light snow already entering the Anchorage Bowl and into the Mat-Su Valley as well. This is all in response to the shortwave trough coming out of the AK Peninsula and soon moving through the Kenai Peninsula. A weak surface low is expected to soon develop across the southern Kenai Peninsula and work its way up along the Gulf Coast before moving into the Prince William Sound by late afternoon. The heaviest precipitation today will be focused along the Kenai Mountains into the western and central Chugach, particularly closer to the coast as the surface low drives reinforces an upsloping component. Much of the Seward Highway from Girdwood south into Seward should receive in the neighborhood of 3 to 6 inches of snowfall, with the Portage- Whittier area receiving upwards of 12 inches. Areas from the western Kenai Peninsula northward through Anchorage and the Matanuska Valley should still pick up about 1 to 3 inches of snowfall as low/mid- level trough axis rotates northward.

Precipitation will taper off for the Kenai Peninsula and Anchorage- MatSu Valley this afternoon, but pick up towards Valdez and Cordova where a couple inches of snowfall will be possible this evening.

Attention on Sunday then turns back to the west as a deepening area of low pressure over the North Pacific will move up near Kodiak Island, bringing widespread gale force (>34kt) and areas of storm force (>48 kt) winds to the Gulf of Alaska and Cook Inlet.
Widespread precipitation will spread from Kodiak Island up into the Gulf Coast as a warm front lifts north throughout the day, bringing an atmospheric river into the coastal mountains. Recent model trends have the low center on a more westward trajectory up the Cook Inlet.
This regime is a bit more favorable for downsloping across portions of the western Kenai northward through Anchorage and the Mat-Su Valley. Meanwhile, heavy precipitation characterized by several feet of snow is likely for the Kenai and Chugach Mountains. For the road system, the heaviest snow is likely for Thompson Pass and Valdez, as well as portions of the Seward Highway. An influx of warmer air is likely to lead to rain/snow mix or rain for some coastal areas such as Seward and Whittier by Monday.

While details remain uncertain, confidence is high the deep upper- level trough will drive another 2-3 areas of low pressure into southcentral Alaska through midweek. A near continuous stream of moisture will result in near continuous snow (/low-level coastal rain) for mountainous areas, with blizzard conditions possible in susceptible areas such as Thompson Pass. A big forecasting challenge with this series of systems will be the degree of 'inland' (including western Kenai and Anchorage area) precipitation as times of cross-barrier flow should subside, allowing precipitation to fill back in across the area.

-Brown

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

An unsettled weather pattern will continue over the Bering and Southwest Alaska through the weekend. The culprit being a persistent upper low with multiple troughs rotating through its broader cyclonic flow. Large scale synoptic lift associated with the low over Southwest is maintaining isolated to scattered light snow showers from the Kuskokwim Delta down into Bristol Bay.
Additional convective snow showers are tracking from the Bering Sea into the Eastern Aleutians and Alaska Peninsula. Gusty conditions will promote blowing snow for coastal regions of Bristol Bay and parts of the Aleutians Saturday morning into Saturday afternoon. Attention then turns to Sunday with the expected development of a stronger upper low.

Models continue to merge a shortwave trough lifting into the AKPEN from the North Pacific on Sunday with the persistent upper low over Southwest Alaska. This should result in moderate to perhaps heavy snow for the Greater Bristol Bay area over the latter half of the weekend into early next week. Increasing winds inland of the coast will spread a threat for blowing snow and potential blizzard conditions from Dillingham into New Stuyahok, Koliganek, and Iliamna. Snow accumulations through Monday morning could approach 4 to 8 inches depending upon where the stronger snowbands develop. A winter storm watch for potential blizzard conditions has been issued,effective Sunday morning through Monday morning.

.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...Somewhat tricky AVN forecast for Anchorage today as an area of snow has already moved into the Anchorage bowl. MVFR CIGs may remain through much of the day with on/off light snow through the morning. Guidance indicates the heaviest potential for snow today will be in the 21-00z timeframe, which could lead to brief periods of IFR CIGs and/or VIS. That said, accumulation through the day should be minimal... with just around an inch expected.
Winds out of the northeast should pick up a bit later with flow out of the Matanuska Valley.

Conditions are expected to improve by this evening as the trough lifts out.

-Brown

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Ninilchik
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Sat -- 12:32 AM AKST     15.41 feet High Tide
Sat -- 05:55 AM AKST     Moonrise
Sat -- 06:29 AM AKST     5.32 feet Low Tide
Sat -- 09:56 AM AKST     Sunrise
Sat -- 12:12 PM AKST     18.44 feet High Tide
Sat -- 02:19 PM AKST     Moonset
Sat -- 04:01 PM AKST     Sunset
Sat -- 07:18 PM AKST     1.31 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Ninilchik, Alaska, Tide feet

Cape Ninilchik
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Sat -- 12:32 AM AKST     15.41 feet High Tide
Sat -- 05:55 AM AKST     Moonrise
Sat -- 06:19 AM AKST     5.52 feet Low Tide
Sat -- 09:56 AM AKST     Sunrise
Sat -- 12:12 PM AKST     18.44 feet High Tide
Sat -- 02:19 PM AKST     Moonset
Sat -- 04:01 PM AKST     Sunset
Sat -- 07:08 PM AKST     1.51 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Cape Ninilchik, Alaska, Tide feet

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