textproduct: Juneau

MID MORNING AND 18Z AVIATION UPDATE

Confidence is increasing on an impactful frontal wave moving up along the plume of moisture THursday night, which is expected to elevate wind gusts for longer for Ketchikan, Metlakatla, and now up to Wrangell. Therefore, extended the wind advisories for Metlakatla and Ketchikan, and raised magnitudes up to at least 50 mph. Conditions continue to look relatively stable from WAA, so not expecting anything drastically higher than that, although areas of elevation greater than 1000 ft could exceed 60 mph from the strong LLJ. Furthermore, expanded Juneau into the wind advisory for gusts up to 40 mph along the initial frontal wave incoming tonight. Due to corresponding higher wind gusts with prolonged moderate to heavy rain in the flood watch areas, added the risk of possibly isolated landslides in steep terrain.

SYNOPSIS

- Another round of light showers impacts the northern panhandle Wednesday morning.

- A larger, more impactful system to move into the Gulf Wednesday, impacting SE AK overnight into Thursday and through the start of the weekend.

- A Flood Watch is in effect for the southern panhandle with rain rates as high as 0.25 to 0.3 inches per hour possible.

- Winds will continue to increase Thursday into the weekend. Currently a wind advisory is in effect for the southern panhandle.

LONG TERM

Active weather continues for the long term as low pressure continues to remain in the Gulf for the start of the weekend. With the low staying in place, some onshore flow will continue allowing for moisture to remain across the area. Guidance today has moved away from the idea of the remnants of Typhoon Koguma impacting the panhandle for the weekend. Instead, GEFS and EPS are pointing towards the low moving into British Columbia. The main low that has been affecting the panhandle will still be in the area bringing increased winds across the southern panhandle. Moving into the start of next week, guidance still has some good divergence on model outputs but conditions could remain somewhat active although there is a chance we see a break in the weather before another low looks to potentially move into the western Gulf by Monday evening.

AVIATION.../Through 18z Thursday/

Predominate VFR flight conditions ongoing across the panhandle this late morning with rain showers and ceilings AoA 3500ft, isolated areas with a SCT to BKN deck around 1500ft. Through the rest of this afternoon and into the evening, VFR flight trends remain the same with winds around 10 to 15kts, gusts up to 25kts. Conditions deteriorate late Wednesday night into Thursday morning as a strong front pushes across the Gulf and inland through 12z Thursday with highest E to SE-ly LLWS chances expected across the southern and coastal terminals. More widespread MVFR or worse flight conditions expected after 12z through 18z and beyond through Thursday as the strong front pushes inland with IFR visibilities expected within heavier showers

MARINE

Inside(Inner Channels): For the most part Wednesday starts out fairly benign with winds under 20 kt. Winds to pick up to small crafts overnight with a few localized gale force 35 kt. Most likely regions include east flow out of Cross Sound and into Clarence Strait from the south possibly Chatham Strait with the southerly flow.

Outside (Gulf and Coastal Waters): Gale force winds Wednesday evening over the gulf waters moving into the coastal regions of the panhandle. Later tonight as the front gets closer to the panhandle the flow exiting the panhandle will pick up a strengthen easterly flow from Cross south into the northeast gulf ahead of the front where winds up to storm force of 50 kt is anticipated. When the Thursday get closer to moving into the panhandle expect to see the winds over the western portions of the gulf and north gulf coast have the winds decrease 20 to 25 kt Thursday to Friday.

HYDROLOGY

/Wednesday night through Friday morning/ A strong incoming atmospheric river will move into the panhandle beginning Wednesday night and continuing at least through Friday morning. Two distinct frontal features make up a bulk of the heavy rain for the central and southern panhandle: The first during Thursday morning through Thursday afternoon, and the next Thursday night into Friday morning. Confidence for the overnight wave is particularly low, with recent guidance indicating a much stronger solution than previously indicated. IVT values look to range between 500-750 kg/ms, emphasizing near 750 on the initial wave. Ketchikan and Metlakatla continue to be the target of opportunity here, with rain rates possibly exceeding 0.3 inches per hour, and up to 0.25 inches elsewhere. These rates are expected to be sufficient enough for at least minor flooding on small creeks and streams.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory from 1 AM to 4 PM AKDT Thursday for AKZ323-325-327- 328. Flood Watch from Thursday afternoon through Friday afternoon for AKZ326>330-332. Wind Advisory from 1 AM Thursday to 4 AM AKDT Friday for AKZ329- 330-332. MARINE...Storm Warning for PKZ644-664. Gale Warning for PKZ022-036-641>643-652-661>663-671-672. Small Craft Advisory for PKZ021-031>035-053-651.