textproduct: Juneau

SYNOPSIS

Key Messages:

- Lingering showers across the southern panhandle through this evening before drier conditions through Friday night.

- Coolest night of the Fall season expected tonight into Friday morning with clearing skies, temperatures dropping into the mid to upper 30s across much panhandle, Yakutat potentially dropping into the low 30s.

- Rain returns to the forecast by Saturday morning as a front pushes into the panhandle with periods of rain lasting through the rest of the weekend.

LONG TERM.../Saturday through Tuesday/

An active weather pattern will persist across SEAK through the forecast period. Multiple fronts/lows will push through the Gulf move into the panhandle over the weekend and into early next week. The big player that will send the fronts into the Gulf and through SEAK will be the remnants of Typhoon Dujuan and associated upper- level low/trough that will slowly swing through southern interior into the Gulf through the weekend into early next week. Between each front, weaker moist onshore flow will keep mostly cloudy skies and showers. The initial front will lift northeastward through SEAK on Saturday, followed quickly by a secondary stronger front pushing east later Saturday night and Sunday. A period of moderate to heavy rain and gusty S-SEly winds are expected with each frontal passage, especially with the Sunday system as deeper moisture feed ahead of front will bring higher precipitation rates. Cooler temperatures aloft with the upper trough will generate modest instability, bringing a potential for isolated thunderstorms, mainly along the Gulf coast. By early next week, guidance continues to indicate the active pattern continuing as the broad upper-level troughing remains over or just west of the Gulf, with an additional front/low lifting northeast through the Gulf into the Panhandle Monday into Tuesday, keeping the potential for moderate to heavy rain and gusty winds. Some guidance is quite aggressive with this low and bringing gales into the Gulf. While model spread and uncertainly remains in regards to the timing, location and strength of this system, overall confidence is high for a wet and active period. While rounds of moderate to heavy rainfall are expected through the period, with around a 10-15% probability of precip rates reaching 6hr/24hr 2-year return interval, each system is fairly progressive and a prolonged duration of heavy rain is not expected. The rainy and cloudy pattern will keep temperatures seasonably cool with highs generally in the 50s.

00z AVIATION

/through 00z Saturday/ No major changes to current aviation forecast as VFR conditions prevail across the panhandle with CIGS AOA 4000ft. Flight conditions will continue to improve through, VFR continuing to prevail as skies gradually clear. Main aviation concern will be limited to coastal and southern terminals, ex Sitka, Klawock, and Ketchikan, as isolated convection and thunderstorm development continues, similar conditions to the previous 2 days with ~20 to 30% chance through this evening before diminishing entirely. With expected clearing skies by late tonight, growing forecast confidence of patchy dense fog development across the inner channel and southern panhandle terminals, added a couple TEMPO groups for Petersburg, Klawock, and Ketchikan for a few hours 11z-15z tomorrow morning for a period of MVFR or worse flight conditions before an expected improvement once again to VFR by 21z Friday.

Winds through this afternoon remain around 10kts or less, with gusts up to 20kts possible, diminishing to near calm and variable overnight into Friday. No significant LLWS concerns through the period as low continues to weaken offshore.

MARINE

Outside: Thursday, a low located near 56N 139W continues to weaken, with southeasterly winds of strong breezes subsiding through the afternoon. As of 1400 Thursday afternoon heavier showers and a thunderstorm or two were out and about along the coast, with storms subsiding by Thursday evening. Current sea state is dominated by southeast wind, driving seas of 7 to 9 ft. Beneath this is diminishing southwest seas along with far south Pacific ground swell at 16 seconds showing on the spectral density; simply put, choppy. Seas will continue to subside Thursday evening, bringing a short break from more concerning waves through Friday afternoon.

All eyes on a multitude of systems across the Bering and along the Aleutian chain. The primary focus for us in the Gulf is a triple point low near 47N 164W which will continue to move northeast into the Gulf by Friday. Main threat is developing easterly strong breezes along Cape St. Elias late Friday, with southeasterly winds increasing to gales Saturday and jacking up wave heights back to 11 to 13ft. For the remainder of the Alexander Archipelago, Saturday, southeasterly winds reach near- gales for the Fairweather Grounds and strong breezes south. These winds will be responsible for fresh seas out of the southeast, driving significant wave heights 12 to 10 ft south of Yakutat, and 8 ft to 6 ft from the Fairweather Grounds to Cape Decision.

One item of note over Thursday, a fetch of strong-gale to storm force westerly winds are developing along the Aleutian Storm Track, serving up decent westerly wave energy by Sunday for our coast. While most of the energy is focused toward the PNW/Canadian waters, the Eastern Gulf coast should pick up on prominent westerly swell 13 to 15 seconds at 10 to 12 ft near Sunday.

Inside: Winds continue to relax across the inside bringing a short break through Friday. Primary threat Friday morning is areas of fog which should break apart through the late morning. Expect southerly winds to start ramping up Saturday morning, becoming widespread fresh breezes by the late afternoon, with localized areas of strong breezes by Saturday night. Simply put, Friday is the best day to get out on the water.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ652-664-671-672.