Marine Weather and Tide Forecast for Adak, AK

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

KEY MESSAGES:

1) Convective Bering Sea showers will continue today.

2) A North Pacific low moves toward the the Aleutians/Alaska Peninsula mid-week.

DISCUSSION:

1) Convective Bering Sea showers will continue today.

Nighttime microphysics overnight showed continued showers moving southward to the Western and Central Aleutians ,though surface observations reported trace to a tenth of an inch of precipitation over a twelve hour period ending at 4:00 am today.
These conditions will continue through this evening as a North Pacific shortwave and a dissipating low off the coast of St.Lawrence Island moves south across the Bering Sea.
Additionally, precipitation decreases rapidly today across the Mainland.

2) A North Pacific low moveS toward the the Aleutians/Alaska Peninsula mid-week.

High pressure in the North Pacific drifts southward as a North Pacific low deepens and moves toward the Eastern Aleutians/Alaska Peninsula into Thursday. The low deepens from 985 mb this morning to 970 mb through tomorrow morning. After the front crosses the AK Pen / Eastern Aleutians late tomorrow morning, a robust area of small craft to gale-force winds extends throughout the southeastern Bering Sea and the Bristol Bay waters Wednesday into Thursday morning. Looking deeper, northerly winds from Dutch Harbor eastward to King Cove have a 70% chance of exceeding 50 mph and a 40% to 60% chance of exceeding 60 mph from the early morning hours to middle afternoon hours. The most likely (60% to 80%) chance for wind gusts in the aforementioned area to exceed 50 mph is Thursday from the late morning hours into the late afternoon hours. As the low begins to slowly pivot east towards the Gulf Thursday, north-northwesterly winds across the southern AKPen and eastern Aleutian Islands further strengthen, bringing the potential for storm-force gusts from roughly Unalaska to Cold Bay and widespread gales through favored bays and passes along the southern AKPen. Across the Southwest Mainland, expect gusty easterly Kamishak Gap winds as well as gusty offshore winds for the Kuskokwim Delta coast and Bristol Bay coast. Also of note, a 40% to 60% chance of northeasterly wind gusts out of Shelikof Strait range from 40 mph to 50 mph.

-Johnston

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

The long term forecast starts off on Friday with a low tracking into the Gulf of Alaska and weakening. Scattered rainfall impacts Kodiak Island and the Southcentral Coast. Higher elevations will likely see snowfall with snow levels at 1500 to 2000 ft. For Southwest Alaska, gap winds over the Unalaska area and Alaska Peninsula quickly diminish as the low moves east. Ridging develops over the Bering, leading to calmer winds and potentially low stratus or fog. Uncertainty with the low's location is present on Saturday, with more or less rain and snow possible for the coast depending on the low's exact position. On Saturday night/Sunday morning, a frontal system moves into the Bering, leading to rain and elevated winds over parts of the Aleutians, but exactly which part is uncertain for now. Southcentral dries out on Sunday as the low is absorbed by a new low moving into Southeast Alaska. A strong North Pacific low is poised to move south of the Aleutians by Monday, which would bring gusty winds and rainfall to the Unalaska and Nikolski area. Southcentral remains drier on Monday.

-JAR

AVIATION

PANC...Winds remain light and variable. Rain showers will be less frequent through this afternoon, but there is still about a 20 to 40 percent chance that a stray shower could move over the terminal and briefly drop ceilings to as low as 1500 to 2500 ft.

Around 04Z this afternoon, ceilings will likely drop below 5000 ft as a low approaches Prince William Sound. There is about a 30 percent chance that precipitation will spread far enough west to bring rain to the terminal tonight, which would increase the likelihood of MVFR ceilings around late afternoon/evening.
Regardless of whether we see another round of rain, ceilings will likely continue to drop to as low as 500 to 1500 ft late tonight as lingering moisture leads to the development of low stratus.