Marine Weather and Tide Forecast for Sitka and, AK

SHORT TERM
No changes in message to the ongoing forecast for the next 24 hours over the land areas. Satellite shows the marine layer off the coast slowly working its way inland into Icy Strait to right about Gustavus with some minor patchy fog around the Klawock area.
Expecting these clouds to retreat promptly in the next few hours as the sun rises properly. Similar to yesterday, warm temperatures of 70 to 80 degrees in the panhandle, with the emphasis on the Haines area for that upper limit. A heat advisory is still in effect for the Haines Highway area by Klukwan, with no change in duration or high temperature. With 850 temperatures hovering between 12-14 degrees C, up to 80 degrees at the surface is appropriate. For marine changes, see the marine section.


LONG TERM
Key messages:

- At the start of the week, wind speeds in marine areas will increase during the afternoon hours as sea breezes kick in. Speeds will decrease in the evenings.

- The ridge breaks down at the start of the week as a weak upper level low makes its way over the northern gulf.

- Precipitation chances return, but rain stays light with low QPF. At the same time, overcast cloud cover returns with slightly cooler temperatures.

Details: Sunday will remain sunny and dry as a ridge of high pressure stays over the gulf. This means clearer skies with warmer temperatures. These temperatures are also evident at 850 mb where temperatures are 10 to 15 degrees C, which builds confidence of maximum temperatures in the 70s.

A pattern change occurs at the start of the week as an upper level low and trough push the ridge away from the panhandle. This will increase cloud cover which will in turn bring maximum temperatures back down to the mid 60s. Along with increased cloud cover, a short wave will bring precipitation chances back to the panhandle late Monday into Tuesday. For the start of the week, QPF totals remain very low with only light precipitation expected.
These rain chances continue and slightly increase mid to late week as a more structured system moves into the panhandle. Although chances increase, no significant rain totals or impacts are expected at this time. The most rain is expected Friday in the northern part of the panhandle.

For winds, most of the panhandle remains light except for sea breezes on Sunday and Monday, that will increase winds for marine waters in the afternoon and decrease in the evening. These sea breezes will be around 15 to 20 kts and continue into the start of the week before cloud cover takes over. The main areas where sea breezes will be present are Lynn Canal and Stephens Passage.
Otherwise, winds along the coast will increase Sunday into Monday morning to 15 to 20 kts as the trough pushes the ridge toward the panhandle. This will slightly increase the pressure gradient until the ridge weakens and moves past the panhandle.

AVIATION
Coastal marine layer and shallow fog continue to dissipate through morning as predominate upper end MVFR to VFR conditions reign across the panhandle, outside of Yakutat which remains socked into IFR flight conditions with CIGS near 600ft.

Expecting similar flight conditions to yesterday, VFR conditions will prevail for the interior TAF sites with CIGS AoA 5000ft and intermittent HZ. For the outer coast TAF sites, marine layer will gradually dissipate/shift offshore through late afternoon with VFR along the outer coast, worst flight conditions for the day will remain around Yakutat through the afternoon. Return of areas of radiational fog and coastal marine layer expected again early Sunday morning with IFR ceilings and intermittent reduced visbys for coastal TAF sites like Yakutat, Sitka, Klawock, and even Gustavus with marine layer likely pushing into Icy Strait once more.

Sustained winds should remain around 15kts or less across the panhandle, with isolated gusts up to 25kts possible during afternoon seabreeze for Skagway. No LLWS concerns through the TAF period.

MARINE
Outer Waters: No changes to wind magnitudes or directions for the outer waters, with widespread fresh to strong NW breezes along the outer coast. However, the marine layer currently over the outer waters have descending clouds to the surface, resulting in widespread fog with visibilities dipping down to 1 NM at times.
This fog will be advecting to the SE over the course of the day.

Inside Waters: Some changes to the ongoing forecast, largely to the Icy Strait and Lynn Canal areas. Strong daytime heating both in Canada today and towards the far inner channels (Juneau, Haines, Skagway) will result in both localized sea breezes and a more pronounced sea breeze between the marine layer over the outer waters and the inside channels. A thermal gradient exceeding 10-15 degrees between the outer waters and inside channels will result in an increasing pressure gradient in Icy Strait for westerly winds. Increased wind speeds in Cross Sound and Icy Strait to up to 25 knots for these areas during the afternoon and evening timeframe, when heating is maximized. Less confidence for the Lynn Canal area, specifically extending the higher wind speeds from Taiya Inlet down to Eldred Rock. Kept what was present in the forecast due to lack of confidence to change it.

HYDROLOGY
An increase diurnal heating over the panhandle in combination with rising freezing levels exceeding 9500 ft over the northern panhandle will increase snowmelt and runoff into streams. The Chilkat River crossed over Minor Flood stage as of 4 am Saturday morning, and a flood advisory continues to be in effect. The Chilkat River will likely stay above minor flood stage and a flood advisory will remain in effect through Sunday before temperatures begin to reduce.

AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...Heat Advisory until 7 PM AKDT this evening for AKZ319.
MARINE...Small Craft Advisory for PKZ021-022-641>644-661>664.