textproduct: Juneau

SYNOPSIS

Key Messages:

- Active weather will continue through the end of the work week as multiple strong systems track along the Eastern Gulf of Alaska.

- The current system is over the southern half of the panhandle, generating widespread wind gusts greater than 40 mph with gusts up to 60 mph for the extreme southern panhandle through 6 PM tonight.

- Aviation conditions continue to be poor due to wind, with multiple PIREPs of ongoing low-level wind shear. Southeasterly to Easterly low- level wind shear reaching upwards of 60kts across the southern panhandle, will begin to gradually diminish past 6 PM tonight.

- Mariners along the coast and southern inner channels should remain weather aware through Thursday. Strong gales to storm force winds are expected to continue through the evening, with a minor wind shift from SE to SSW behind the front. Southerly seas along the coast currently building to around 25 ft will begin to diminish overnight. Many inner channels will feel gale force conditions with the strongest winds near Prince of Wales Island, Clarence Strait, and major ocean entrances. Winds and seas begin to subside Thursday.

- To end the work week, another strong low will move up from the south, primarily impacting the southern panhandle with wind gusts greater than 40 mph, gale force winds in the marine areas, and additional aviation wind concerns.

LONG TERM

/through Monday/ Active weather continues into the long term as a low tracking north from the Pacific into the Gulf of Alaska looks to bring the next round of active weather. Right now, there is still decent disagreement among deterministic and ensemble guidance with the track of this low. These solutions are split between tracking north along the coast and potentially bringing significant winds to large portions of the panhandle. The second solution is that the low tracks inland over Prince of Wales Island and Sumner Strait. This second solution would limit the high wind potential to the southern panhandle as it tracks through the area.

Regardless of the track of the low, precipitation is expected to continue for the panhandle with rain for most places and snow for the higher elevation locations. Current thinking is that most places will see around 6 hour rain amounts jumping up to 0.5-0.75" at their max. After this system moves through, the concern then turns to the next potentially impactful low to move into the area for next week which could bring significant moisture to the panhandle over a few days.

AVIATION

/through 00z Friday/ Flying conditions will be impacted through the period as multiple lows track along the E Gulf of Alaska along the coast of SEAK with rain, variable VIS/CIGS, and strong LLWS expected through Thursday night.

Main aviation threat through the period will be the LLWS across much of the central and southern panhandle as 2 fronts track inland through 00z Friday across the central and southern panhandle TAF sites, from Sitka to Petersburg Southward.

A first strong front is currently pushing north through the eastern Gulf, with associated front lifting through the southern and central panhandle. This first front will bring a period of strong to high wind gusts across Sitka, Ketchikan through 03z this evening, before rapidly diminishing. A break expected overnight before another front pushes into Prince of Wales and Sitka by 12z to 15z with LLWS 30 to 40kts starting SE-ly turning SW-ly into Thursday morning. Anticipating predominate MVFR to VFR flight conditions through Wednesday night into Thursday morning with CIGS 2000 to 5000ft and Visbys between 3 to 5 SM as fronts move inland.

MARINE

/through Friday night/ Mariners planning on navigating Chatham and Sumner ocean entrances should be aware of incoming southwesterly swell energy Thursday.

More details below.

Outside (Gulf and Coastal Waters): As of 2pm Wednesday, a storm force low is pushing north into the northern coast, with the low center located near 55N 143W. Coastal buoy are reporting sustained southeast gales, but they are missing the highest winds of strong gales, as seen by ASCAT satellite wind passes. One item of note is buoys reporting seas less than 20 ft but that was anticipated given the responsible fetch location and direction; there are 25 to possibly 30 ft waves in the eastern gulf, just west of buoy 83 and 84, pushing toward Cape St. Elias. Furthermore, a secondary wave system fed by gale to strong gale force southwesterly winds is a few hundred miles offshore of Haida Gwaii, which will push significant southwesterly swell toward Chichagof, Baranof, and Prince of Wales tonight. Mariners navigating our coast Thursday, especially near Chatham and Sumner Ocean entrances, should be aware of this southwesterly wave energy.

While seas and winds diminish across the region Thursday night, we continue to monitor the progression of a secondary low moving into the southern Panhandle Friday, freshening southerly winds back up to gale force in Clarence Strait, with near-gales along Prince of Wales. Mariners planning on transiting the northern coast Friday should be aware of the potential that this low tracks into the Fairweather grounds, bringing winds briefly up to gales Friday. As of Wednesday afternoon, our published forecast, and confidence, indicates NE winds of moderate to fresh breezes out of Cross Sound for Friday. Stay tuned to NOAA WX radio or weather.gov/juneau for updates.

Inside (Inner Channels): Winds continue to increase through the inner channels Wednesday afternoon into tonight in response to a storm force low in the central gulf, with the central and southern Panhandle seeing the brunt of southeasterly gale force winds. Mariners navigating Lynn Canal are experiencing moderate breezes out of the north given the parallel surface pressure gradient and parent low location in the gulf. However, overnight Wednesday near 7 pm there will be a southerly surge in Lynn Canal, but sustained winds should remain below 25 knots. Thursday morning winds begin to subside, with many inner channels feeling southeasterly winds of moderate to fresh breezes. Friday a secondary low will slide into the Panhandle, freshening winds back up to gale force for Clarence Strait and near gales for Sumner and Frederick. There is a lot of uncertainty on the track of this low, mariners should monitor NOAA WX Radio or weather.gov/Juneau for updates.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory until 9 PM AKST this evening for AKZ323-327. High Wind Warning until 6 PM AKST this evening for AKZ328-330- 332. MARINE...Gale Warning for PKZ033>036-642>644-651-652-662>664-671-672. Small Craft Advisory for PKZ021-022-031-032-053-641-661.