textproduct: Juneau

SYNOPSIS

Key Messages:

- A stronger weather system and weak atmospheric river will bring gusty winds, elevated seas, and moderate to heavy rainfall for the weekend.

- Unsettled conditions are expected to persist into next week.

LONG TERM.../Monday through Wednesday

Little change to the long term forecast and overall message as the pattern looks to stay unsettled. Low pressure will remain nearly stationary and very slowly weaken over south-central Alaska through the period. This will send multiple fronts across the panhandle and also work to reinforce persistent onshore flow. As a result, we will continue to see periods of rain, especially Monday into Tuesday with perhaps a bit less widespread precipitation for a time later Wednesday. As weak high pressure builds to our east over British Columbia and the pressure gradient tightens, we may see intervals of gusty winds, particularly in the favored areas over the northern panhandle. Model guidance is also suggesting that we could see a few thunderstorms, mainly over the coastal waters, but confidence was too low to include in the forecast at this time.

AVIATION

A warm front moving north through the panhandle and northern Gulf will bring a fresh round of rain to most of the area this morning. Later this afternoon and into Saturday night winds will pick up quickly and could gust 20-25 kt at sites further inland, and nearer the coast gusts of 30-35 kt are possible. With the quickly changing environment and wind setup, LLWS is also likely and has been included in several TAFs, mostly along the coastline.

Ahead of this next front, most of the daytime Saturday will be spent in a lull with raised cigs and on/off lighter rain. As such, the current MVFR/VFR conditions will improve to almost entirely VFR during the day. With the stronger winds and increased rain tonight expect those cigs to drop significantly, leading to mostly MVFR/IFR conditions throughout the panhandle later tonight.

MARINE

Outside: The developing gale force low continues to move into the Gulf just south of Kodiak Island Saturday morning, with strong breezes to near gales offshore in the early morning. Winds will quickly increase in the morning to E-ly gale force to strong gales, with gusts to storm force, along Cape St. Elias associated with the first front moving in. The next front will bring winds up along the rest of the waters along the outer coastline from strong breezes to near gales in the morning to SE-ly gale force winds this evening into tonight, with potential for strong gales near the Fairweather Grounds. Winds will shift to S/SW behind this front and diminish late tonight into Sunday morning, down to a fresh breeze during the day Sunday.

Seas will quickly build up through the morning to 8-13 ft, with the northern coastal waters reaching seas near 17 ft by the afternoon. Seas will continue to build Saturday night into Sunday to around 15 ft, with an area of 20-22 ft seas possible along the NE coastal waters near the Fairweather Grounds and Cape St. Elias. Multiple wave systems will be present; large and confused seas. Seas expected to begin to diminish Sunday, becoming 7-9ft by Sunday night.

Inside: Winds across northern Lynn Canal continue to stay around 15-20 kts Saturday morning, before beginning to diminish into the later morning hours. The main concern for the inner channels however is the front moving across the area Saturday evening into the overnight hours, bringing elevated SE-ly winds across much of the area as it pushes through. Icy Strait is expected to pick up ahead of this with easterly winds around a fresh breeze, as well as near Young Bay this morning. As the front pushes into the area during the evening, winds will pick up from the E to SE starting first with the central and southern inner channels, before moving up into Glacier Bay and Lynn Canal late Saturday night. Largely expecting winds to pick up to a strong breeze to near gale as this passes, before diminishing after it moves through and switching to a more S-ly direction into Sunday. Winds Sunday into Monday will remain still a moderate to fresh breeze, with strong breezes up along Lynn Canal

HYDROLOGY

A stronger system is expected to move into the panhandle Saturday into Sunday, bringing periods of moderate to heavy rain. During the peak of heavier rainfall during the overnight hours, rain rates could exceed 0.15 inches per hour. Moderate to heavy rates are expected to continue for any given location for a period of around 12-18 hours before decreasing. Total rainfall accumulations for the event are expected between 1.5 - 3.0 inches, with greatest amounts in the central panhandle. Upwards of 5 inches will be possible for higher elevations. Due to the short nature of the heavier rainfall, smaller creeks and streams will rise quickly, but are not expected to flood.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Gale Warning for PKZ641>644-651-652-661>664-671-672. Small Craft Advisory for PKZ011>013-021-022-031>036-053.