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PKZ732 Marmot Island To Sitkinak Out To 15 Nm- 358 Am Akst Tue Nov 28 2023
.gale warning today and Wednesday...
Today..S wind 35 kt. Seas 12 ft. Rain.
Tonight..SE wind 30 kt becoming E 20 kt after midnight. Seas 12 ft. Rain.
Wed..N wind 25 kt becoming nw 35 kt in the afternoon. Seas 9 ft. Rain.
Wed night..W wind 35 kt. Seas 11 ft.
Thu..NE wind 25 kt. Seas 8 ft.
Fri..NW wind 20 kt. Seas 11 ft.
Sat..NE wind 15 kt. Seas 8 ft.

PKZ700
No data

FXAK68 PAFC 281445 AFDAFC

Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 545 AM AKST Tue Nov 28 2023

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Today through Thursday night)...

Conditions are fairly quiet across Southcentral this morning, with just a few areas of showers due to low level instability and some weak short-waves aloft. However, the upper level flow remains progressive, so this is just a very brief break in the impactful weather. A moderate strength low will track northward across Southwest Alaska today with a trailing cold front tracking east into the western Gulf and Cook Inlet. A ridge will build downstream of this, leading to rapidly tightening pressure gradients. This will lead to strengthening southeasterly winds region-wide, with the typical strongest winds through gaps in the Kenai and Chugach Mountains, including Turnagain Arm and the Knik River Valley. The cold air aloft that moved into Southcentral yesterday has resulted in fairly steep low level lapse rates (in excess of 7 degrees C/km on the 12Z Anchorage sounding). This instability will lead to vertical mixing in the low levels, with stronger winds aloft mixing down to the surface. As a result, winds will be more widespread than they would be in a stable environment. Have issues a special weather statement to highlight strong and gusty winds this afternoon and evening from the Kenai Peninsula to Anchorage, the Matanuska Valley, and the southern to western Susitna Valley.

Meanwhile, the arrival of the cold front combined with upslope flow will lead to increasing precipitation for Kodiak Island, the Gulf coast and portions of the Kenai Peninsula. Despite the cold air advection yesterday, there is still an above freezing layer near the surface and the wind today will lead to further warming.
Therefore, precipitation will be primarily in the form of rain at sea level, with snow in the mountains.

An amplifying trough over the North Pacific will lead to cyclogenesis this afternoon, with a deepening low then tracking northward into the Gulf of Alaska tonight through Wednesday. Low level flow over Southcentral will gradually back from southeast to northeast as this low moves into the Gulf, allowing winds to diminish overnight tonight through Wednesday morning. There remains some uncertainty in the ultimate track of this low, with some model guidance keeping the low down over the Gulf offshore and other solutions tracking the low up toward the Kenai Peninsula. This will make a big difference in the wind and precipitation forecast for Wednesday/Wednesday night. The farther north track would push the leading front onshore bringing stronger winds and heavier precipitation, especially for the interior Kenai Peninsula from Girdwood down the Seward Highway corridor. It could also lead to some precipitation spreading over the coastal mountains to inland areas of Southcentral. For now, have taken a middle ground solution.

The upper trough will ultimately lift northward across Southcentral Thursday, driving the remnants of the low into Southcentral. It looks like it will be in a much weakened form, but will bring a chance of snow to interior areas. The upper levels keep moving, with another trough moving into the Gulf Thursday/Thursday night.
It does look like the upper flow will become more zonal, so any surface lows that spin up look like they will remain well south in the Gulf as we head through the end of the week. This would mean mostly dry weather for Southcentral with seasonable temperatures.

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

An upper-level trough spreads from the Kamchatka Peninsula across the Aleutians and into Southwest Alaska with an embedded upper low located to the west of St. Lawrence Island. Convective snow showers continue to blanket much of the Bering and Aleutians as cold air streams east over the comparatively warm sea surface.

A notably potent shortwave and attendant surface low over the Alaska Peninsula this morning are tracking northeastward into the Bristol Bay area. The low will continue moving very quickly northward through the Lower Kuskokwim Valley today before exiting to the north by this evening. An intense but fairly brief round of snow will follow this low north today, while enough warm air works in to the east of the low center for a period of mixing or changeover to rain today across the southeastern portions of Bristol Bay. The heaviest snowfall will mostly be focused over the Kilbucks and Kuskokwim Mountains, but as much as 3 to 5 inches of accumulation will be possible for surrounding spots including Togiak, Aniak and Sleetmute before the low moves off to the north late on Tuesday. Strong and gusty winds across Bristol Bay and Lower Kuskokwim Valley, in addition to gale force winds over Bristol Bay and the coastal waters south of the Alaska Peninsula, will diminish by tonight with the exit of the low. Conditions across Southwest will become a bit calmer and cooler later in the week.

Further to the west, a strong front reaches the western Aleutians on Wednesday morning and will continue lifting east across the Bering and rest of the Aleutians through Thursday. Steady precipitation and gale force winds will accompany the front. The low itself will track near the western Aleutians by early Thursday morning. Model agreement with this system begins to diverge later Thursday morning with respect to low center placement, the progression of the front, and a subsequent secondary low formation along the front. Nonetheless, the Bering and Aleutians can expect to see generally active weather through at least the end of the week with this system.

AF

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

The long-term forecast period begins Friday morning with fair model agreement depicting a broad upper-level trough stretched across the Bering Sea into the Gulf of Alaska, creating several surface low pressure centers in the southeastern Bering and northwestern Gulf. These lows will draw westerly gales across the Aleutian Chain and easterly gales across the northern Gulf coast into Prince William Sound. Generally a showery, wet pattern will be in place across all of Southern Alaska, with areas such as the lower Kuskokwim Valley, and Copper River Basin seeing relatively less precipitation than surrounding regions. Looking into Saturday model uncertainty increases, with some solutions keeping a low pressure center spinning near Bristol Bay, while other solutions retreat the low to the Western Bering. These discrepancies lead to a difficult forecast as to the behavior of the Bering early next weekend. By Sunday and Monday, model disagreements become severe with some solutions keeping a low in the Southern Bering and granting Southcentral a reprieve in rain and winds. While other solutions spin up a new low pressure center in the northern Gulf of Alaska coast that would bring another strong shot of precipitation and strong winds to the Southcentral coastline, while keeping the Bering relatively benign. Overall, a wet pattern for the Aleutians and Southcentral regions, and looking colder and drier from mid to late week for Southwest Alaska.

CL

AVIATION

PANC...Gusty southeasterly winds will continue through tonight, with the highest winds expected mid-afternoon through this evening, ranging from 15-22 knots sustained and gusts reaching 30-35 knots. Winds diminish and transition to northerly early Wednesday morning. Flow aloft may hold on to southeast winds longer after surface winds have shifted, which may lead to some wind shear beginning around 12Z Wednesday.

KM

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Jap Bay
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Tue -- 02:23 AM AKST     7.42 feet High Tide
Tue -- 07:33 AM AKST     2.96 feet Low Tide
Tue -- 09:22 AM AKST     Sunrise
Tue -- 11:55 AM AKST     Moonset
Tue -- 01:32 PM AKST     10.30 feet High Tide
Tue -- 04:42 PM AKST     Sunset
Tue -- 04:53 PM AKST     Moonrise
Tue -- 08:35 PM AKST     -1.23 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Jap Bay, Alaska, Tide feet

Three Saints Bay
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Tue -- 02:18 AM AKST     7.52 feet High Tide
Tue -- 07:30 AM AKST     2.96 feet Low Tide
Tue -- 09:22 AM AKST     Sunrise
Tue -- 11:56 AM AKST     Moonset
Tue -- 01:27 PM AKST     10.40 feet High Tide
Tue -- 04:41 PM AKST     Sunset
Tue -- 04:51 PM AKST     Moonrise
Tue -- 08:32 PM AKST     -1.23 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Three Saints Bay, Alaska, Tide feet

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