Area Forecast Discussion

SHORT TERM

The weak frontal system associated with a shortwave trough impacting the panhandle continues to move over the panhandle and exit into British Columbia. Light, occasional rain with mostly weak winds outside of Lynn Canal is leading to patchy fog, mist, and low clouds. As modest ridging builds behind the shortwave, looking to see at least some brief drier weather ahead of the next round of rain. Given the moist conditions and ridging aloft, fog concerns continue throughout the morning, with dense fog around the Yakutat area at time of writing. Expecting to see this fog lift to a low cloud deck by the morning hours, coinciding with the next frontal band and surface southwesterlies.

The next band looks to be born out of the triple point of a stronger Bering System. While rain is not much of a concern, with mostly light rain, stronger winds in Lynn Canal and Skagway remain a concern going into Sunday. As the front traverses eastward, surface divergence looks to continue to build pressure in the southern half of the panhandle. This, combined with lee troughing, looks to create substantial pressure gradient flow in Lynn Canal, and parts of Icy Strait/Cross Sound as the energy moves over. A wind advisory has been issued for the Skagway area, for wind gusts up to 45 mph.

Lowest confidence in this forecast is both in precise timing of rain ending and the extent of fog development with consistent low level moisture.

LONG TERM

/Monday through the week/ A ridge pushes into the Gulf of Alaska late Sunday into early Monday. This ridge is likely to lower precipitation chances across the area with the exception of the far north where onshore flow will continue. Even with continued showers into the start of the week, precipitation totals remain on the lower side for Monday. For the northern gulf coast, near Yakutat, 24 hour QPF is most likely to be around 0.5 to 0.6 inches. Depending on the exact location of the ridge, this area has a 20% to 30% chance of seeing around 0.8 inches in 24 hours. Precipitation amounts greatly decrease as you move farther south with areas from Cape Fairweather to north of Frederick Sound seeing 24 hour rain amounts around 0.2 to 0.4 inches. Upper elevation areas, especially over the northern panhandle could still see snow during the overnight hours.

As we get into mid week, precipitation chances decrease even more with only a few areas of light to moderate showers possible. Looking at temperatures, again the far northern portions of the area could see low overnight temperatures to around freezing allowing for periods of snow or a wintry mix overnight. Otherwise, as we get further into the week, daily high temperatures will be around normal with highs in the mid 40s to low 50s. There is a chance that the far southern panhandle could see even higher temperatures into the mid to upper 50s depending on if the ridge allows for drier conditions, and in turn less cloud cover. The next organized system moves into the area late next week once again bringing widespread precipitation. We will continue to monitor this late week system due to the model spread on when this system reaches SE AK.

AVIATION

Weakening front exiting the area to the east is still bringing some precipitation and lower ceilings to most of the panhandle this morning. Ceilings are generally MVFR (1000 to 1500 ft) this morning though some areas of LIFR ceilings (200 to 300 ft) can be encountered in the vicinity of Petersburg, Wrangell and Hoonah. Visibility conditions are better with mainly VFR through some isolated areas down to 3 miles can be observed here and there (Petersburg may have lower vis as well down to 1 1/2 miles at times). Meanwhile, the NE gulf coast near Yakutat has seen its mid level cloud layer clear out overnight leading to fog formation with visibility down to 1/4 mile and ceilings down to 300 ft at times. Generally expect conditions to improve across the area into midday with ceilings and vis improving to 2500 ft and 6 miles or better in most areas as the front moves out and any fog diminishes. The northern half of the panhandle (north of Sumner Strait) tonight will see ceilings coming down again to around 1500 to 2500 ft by late tonight with periods of rain moving back in as a different weak front moves in from the west that will persist into Monday morning before improving.

Winds are generally light (15 kt or less) both at the sea level and aloft. Exception is northern Lynn and Skagway/White Pass with southerly winds of around 15 to 20 kt currently. These winds are expected to increase as soon as midday to around 25 kt with gusts up to 40 kt and are expected to persist into Monday.

MARINE

Outside waters: Westerly to northwesterly winds, driven by the somewhat flat ridge in wake of the frontal passage over the panhandle will give way to southerly winds associated with the next front. Main areas of concern are along the NE gulf coast, with special emphases near land to the east of Cape Suckling. As the frontal passage moves eastward in the gulf, a barrier jet up to 30 knots is expected to setup in the NE gulf coast. This is expected to transition to westerly/southwesterly behind the front, associated with stronger CAA, gustier winds, and building seas to 8-12 ft at 9 seconds overnight Monday night into Tuesday.

Inside waters: Mostly light winds, low clouds, and misty conditions reducing visibilities are present in the inner waters, with these wind conditions expected to continue through the day for the southern half of the panhandle. For the northern half, winds in Icy Strait, Glacier Bay, and Lynn Canal are expected to pick up during the late morning to early afternoon. Lynn Canal is currently around 20 knots, with conditions not looking to improve until Monday as the pressure gradient relaxes.

AJK WATCHES / WARNINGS / ADVISORIES

PUBLIC...Dense Fog Advisory until 10 AM AKDT this morning for AKZ317. Wind Advisory from 1 PM this afternoon to 7 AM AKDT Monday for AKZ318. MARINE...Small Craft Advisory for PKZ012-013-021-022-643-644-651-652- 662>664-671-672.