textproduct: Juneau

UPDATE.../to add the 18z aviation section/

SYNOPSIS

Key Messages:

- Showers tapering off in the southern panhandle, with skies clearing in the northern panhandle

- A weak front will push into the southern outer coast this morning, preceding a more organized front moving into the southern and central panhandle Monday into Tuesday

- Skies expected to clear out again by Wednesday night

LONG TERM.../Monday through the work week/

The long term forecast has been adjust slightly, particularly for Monday night into Tuesday. A 500 mb low near the Aleutian Chain is expected to dig southeast into the central gulf, enhancing the >75 knot jet to the south. The area of upper level divergence is then expected to move over the southern two thirds of the panhandle by Monday night, bringing additional showers and breezy conditions. At the surface, a slightly stronger than expected, gale force system will slide southeast, with the associated front moving northwards from the south over the panhandle. Largest question for this system is how far north the moisture will move, as the parent low is dropping south. Areas from Angoon to Icy Strait and Juneau, therefore, are the most uncertain with this forecast, with the added benefit of cold temperatures and snow accumulation. Due to the negative trough axis, it is possible to have a south to north band of terrain enhanced lift over the aforementioned areas. However, with moisture being the main limiting factor, relative short duration, and a present dry layer that moisture will need to punch through, not expecting large accumulations at this time. Liquid equivalent probabilities have around a 20-40% chance for areas that could receive accumulating precipitation (mainly Juneau and Icy Strait) to exceed 0.2 inches every 6 hours, which would translate into 6 inches over a 12 hour period. Will need to monitor this situation closely going forward, but current forecast represents a more realistic forecast of around 3 inches Monday night into Tuesday for these areas. For Angoon, Tenakee Springs and south, the dominant precipitation type could be snow, but warm wet bulb surface temperatures are expected to limit any snow accumulation.

For down south, expecting largely all rain, except for possibly the upper elevations of PoW Island early on. Gales off the western coast of PoW Island is expected to translate into wind gusts for the western portion between 40-50 mph. Could see these gusts for Metlakatla and to a lesser extent Ketchikan; however, as this front is more easterly in nature, these areas could see less wind than expected.

Wednesday sees another break in precipitation, clearing skies during the day and night, and diurnal temperatures with highs in the mid 30s to low 40s and lows in the mid 20s to low 30s.

Late week sees another frontal feature move into SEAK, bringing mostly warm enough temperatures for rain throughout the panhandle at sea level, and more breezy conditions.

AVIATION.../Until 18Z Monday/

Most areas will experience VFR flight conditions for majority if not all of the TAF period. Some isolated to scattered snow showers are present off & just near the Outer Coast of the Panhandle. They will gradually drift farther into the Panhandle as we progress through the period, bringing periods of primarily MVFR CIGs &/or VISs with potential temporary dips into the IFR category under a heavier snow shower, mainly around the central Outer Coast / PASI area. These will generally stay south of the Icy Strait area through this evening. Snow showers are expected to continue across the southern 3/4ths of the Panhandle up to the Icy Strait / Juneau area & eventually making it up to PAGS into Monday with the snow showers increasing in frequency & intensity late Sunday night into Monday. Expect more frequent MVFR & dips into IFR conditons due to the snow showers becoming more numerous into Monday. Benign SFC winds & LLWS remain expected through the period.

MARINE

Outside (Gulf and Coastal Waters): Light to moderate breezes continue for the Gulf today. These winds will persist through the day as high pressure is over the area bringing just some showers to the area as they rotate around the high. Wave heights are expected to remain less than 6 ft for most of the Gulf today with the light to moderate breezes. Winds are expected to increase to strong breezes later tonight for the northern gulf as a weak front approaches the area. Winds are then expected to diminish somewhat headed into Monday morning before we see winds start to increase again in response to a low moving through the area before finally diving to the south. Wave heights will also increase from 3-6 ft to 18-25 ft as this next low affects the area for the start of the week.

Inside (Inner Channels): Northerly outflow winds continue today, albeit a little less strong with moderate to fresh breezes being reported. Elsewhere, winds remain fairly light. Winds today are expected to be on the downward trend for most locations that are already not light. Wave heights are expected to drop to less than 3 ft with the light winds. This will be short lived though as outflow winds and waves are expected to return in response to a low moving past the area before diving south later this week.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ644-652-664-671-672.