textproduct: Juneau

18z AVIATION

/through 18z Friday/ Predominate VFR flight conditions across the panhandle with ceilings AoA 3000ft and prevailing visibilities greater than 6SM as the low over the eastern Gulf of Alaska continues to churn. Flight conditions will continue to improve through the afternoon, 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, hinted at with a BCFG and lowered SCT deck. Will reassess at the 00z TAF issuance as further forecast confidence grows as this will be highly dependent on speed of cloud dissipating.

Winds through this afternoon remain ~10kts or less, with gusts up to 20kts possible. diminishing to near calm and variable overnight into Friday. No significant LLWS concerns, however with low stationed in E Gulf and broad ESE- ly winds across Baranof Island ~30kts, could create some localized mountain wave action near Sitka, albeit not high enough confidence to include in a TAF.

SYNOPSIS

Key Messages:

- Lingering showers across portions of the region today.

- Cooler, seasonable temperatures to continue, with daytime highs generally in the 50s.

- Mainly dry weather Thursday night into Friday as high pressure moves in temporarily ahead of the next system to affect the panhandle by 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.

MARINE

Inside(Inner Channels): A weakening area of low pressure is generally leading to winds of 5-10 kts in the inner channels. Based on the pressure gradient orientation, the strongest winds are generally expected in E/W oriented channels, such as Icy Strait. This low pressure system in the Gulf is expected to continue to weaken, and lead to weakening winds as well.

Behind this system, weakening winds are expected to lead to fog development in the inner channels. Southern Chatham Strait and Fredrick Sound appear to have the highest chances for fog development Friday morning. As the next front approaches from the west early Saturday, this will lead to increasing winds and waves for the region. By Saturday evening, the strongest winds look to be in Northern Lynn Canal.

Outside (Gulf and Coastal Waters):A low pressure system in the Gulf of Alaska is leading to increased winds and waves. Due to the location of the low, the strongest winds are currently in the Gulf, where there are several small craft advisories through the afternoon. As the system weakens, expect winds to weaken as well. A frontal system currently impacting Southwestern Alaska is expected to move toward SE Alaska, but it will weaken as it does so. The highest confidence in the strongest winds with the second frontal band are from Icy Bay to Cape Suckling.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...None. MARINE...Small Craft Advisory for PKZ662>664-671-672.