Marine Weather and Tide Forecast for Ketchikan, AK

SYNOPSIS

Key Messages:

- A low in the northern Gulf of Alaska will keep sending periods of moderate to heavy snow showers across the northern and central panhandle. Due to the showery nature of the snow, accumulations will be highly variable with periods of melting in sunny breaks. Winter Weather Advisories have been extended through Friday morning.

- A strong low may move up from the south and impact the panhandle over the weekend.

SHORT TERM
No major changes to the short term forecast as the pattern remains nearly identical through the remainder of the week. An area of low pressure in the northern gulf anchored by a stationary trough will continue to send numerous to widespread showers across the panhandle. Visibilities in heavier showers will frequently drop to 1SM and some are dropping as low as 1/4SM.
Given the difficulty with timing the weaker impulses within the broader area of snow showers, opted to continue with dayshift's thinking, and extended the winter weather advisories out across areas north of Sumner Strait through early Friday morning, with accumulations ranging anywhere from 8 to 16 inches. Some isolated locales may receive less or more, depending on how sheltered they are from the current flow pattern. Friday itself should feature a diminishing trend in shower coverage, at least initially, although this will prove to be short lived as stronger shortwaves will begin sweeping through SE AK shortly thereafter, continuing through the weekend. For additional information, see the long term forecast discussion.

The southern panhandle will receive lower snow accumulations through the remainder of the week, driven by slightly less favorable onshore flow conditions and warmer temperatures and stronger diurnal heating of the March sun.

LONG TERM
(Friday through the weekend) Low pressure is expected to remain in the Gulf of Alaska for the start of the long term period. This will continue to bring showers to the panhandle with rain and snow possible. With high pressure remaining in the Bering Sea, colder air will continue to move down the back side of the high pressure and into the low positioned over the Gulf. This will help to reinforce the showers. With the breaks between showers, temperatures will have the opportunity to rise during the day time hours with the increasing amount of daylight being experienced. This will also help to limit accumulation amounts during the daytime. Potential for accumulating snow looks more favorable during the evening and overnight hours.

For the extended portion of the long term forecast, we continue to look cooler than normal for this time of year with near normal to above normal potential for precipitation across the panhandle.

AVIATION
/Through Thursday morning/...Onshore flow from a low in the northern gulf continues through the period, sending widespread showers into the panhandle. The northern half of the panhandle is cold enough to see snow with these showers, though the southern half is sitting just at or above freezing and may see rain mix in. Due to the path of these showers and the cold temperatures aloft, snow is still expected to be the predominant precipitation type, even with Ketchikan and Klawock sitting around 34 to 36 degrees. Looking at satellite, the more enhanced showers seem to be tracking through the northeastern gulf and through the northern panhandle. During heavier showers, VIS may drop to 1 SM or less with CIGs AoB 1000 ft, with many locations jumping between IFR to LIFR conditions. In between showers, low broken CIGs may keep MVFR conditions around, but a majority of locations should see intermittent VFR conditions return through the day. Based on what has been observed already through the morning, there looks to be a very low broken layer and a mid-level overcast layer that moves through with most showers, with the overcast layer opening up to multiple mid-level broken layers in between showers.

For now, TAFs have been written to reflect the overall VFR to MVFR prevailing conditions with multiple TEMPO and PROB30 groups scattered throughout to indicate heavier shower potential. Expect periodic amendments in certain locations to add TEMPOs for these bands of showers. It still looks like potential for a more organized band of showers to move into the area Wednesday night, which may reduce flight conditions across the southern third of the panhandle.

MARINE
Inside (Inner Channels): Winds will remain predominantly southerly across the inside channels. The one place that continues to see northerly winds is over N lynn Canal. Winds over N Lynn Canal are anticipated to become southerly through the day on Wednesday, with the exception of the far north near Taiya Inlet.
Strongest winds remain over Stephens Passage from Midway Island to Five Finger Light House with gusts up to 40 kts. Otherwise winds across the inner channels remain around moderate to strong breezes, 10 to 20 kts. Significant wave heights remain around 2 to 4 ft across the area, with slightly higher waves across Stephens Passage, Cross Sound and ocean entrances.

Outside (Gulf and Coastal Waters): A broad low will remain in the northern Gulf of Alaska through the duration of the week, bringing with it winds of 20 to 30 kt and isolated areas up to 35 kts possible in the far northern gulf. Winds across the southern gulf will be predominately W to SW while winds across the northern gulf will be predominately E to NE. There will likely be times of gusty winds and variable winds as the broad low sends showers through the gulf into the panhandle. Waveheights will remain more on the unsettled side, with 8 to 12 ft expected with southerly swell continuing through mid week. Over the weekend, a strong low moves up from the south.

AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...Winter Weather Advisory until 4 AM AKDT Friday for AKZ317>321- 323>326.
Winter Storm Warning until 7 PM AKDT this evening for AKZ322.
Winter Weather Advisory from 7 PM this evening to 4 AM AKDT Friday for AKZ322.
Winter Weather Advisory until 10 PM AKDT this evening for AKZ328.
MARINE...Small Craft Advisory for PKZ022-031-034-053-641>644-651-652- 661>664-671-672.