textproduct: Juneau

UPDATE.../to add the 18z aviation discussion/

SYNOPSIS

Key Messages:

- Lingering rain and drizzle will diminish through the day.

- Onshore flow will keep the warmer-than-normal temps in place. Colder weather begins to slide south into the area Friday night.

- This weekend into next week, long range models are still hinting at a weather pattern that has been known to produce heavy snow. High uncertainty at this time but worth watching closely.

LONG TERM.../Friday through Monday/

A pattern change going into this weekend is looking to bring cold temperatures, heavy precipitation, and strong winds to the panhandle into early next week.

A system advancing into the northern gulf through Friday will send a front into the panhandle overnight Friday before stalling in the northern gulf through the weekend, funneling consistent moisture over the panhandle. This front will bring moderate to heavy rain rates to the area, with around an inch expected for a majority of locations and persisting at similar rates through the weekend. A cold air mass aloft shifts into the Yukon and continues to moves southward through the weekend. A tightening pressure gradient over the northern panhandle will increase outflow winds through the weekend, helping to funnel the colder air south into the panhandle. Decreasing temperatures with ample available moisture will increase the potential for heavy snowfall in the northern panhandle, extending south through the weekend and into next week. Highest confidence of snowfall remains across the far N Panhandle and a Winter Storm Watch has been issued for Haines and Skagway starting Friday night, continuing through Saturday. Looking elsewhere, Yakutat will also see higher amounts of snow, but currently expecting just below warning levels. Forecast becomes more of a challenge moving towards the Icy Strait Corridor, starting as rain and transitioning into a mix by Saturday, limiting potential amounts initially. Snow level drop south following the colder temperatures, snow potential will also move further south towards the corridor, and the rain/snow mix will then follow into the central panhandle. Stay tuned to the forecast moving into the weekend as details come into clearer view regarding potential amounts and refined timing for the Icy Strait Corridor and Yakutat.

As the gale force low moves into the northern Gulf and a high sets up to the north of the panhandle into this weekend, northerly flow begins to set up over the northern panhandle into Lynn Canal. This cold air mass to the north contributes to the colder temperature trend over the weekend and into early next week, alongside bringing stronger winds down Lynn Canal. These winds will begin to increase Saturday into Sunday with northerly gales in northern Lynn Canal with 35 to 40 kt winds by Sunday afternoon as the gradient tightens over the northern panhandle. Winds will increase in Skagway at this time, however the stronger sustained winds will likely stay below 30 mph, with the northerly wind not being expected to be strong enough to dry out the air too much enough to reduce the snowfall amounts. Other land areas will see an increase in SE winds as the front moves through, with diminished winds between the waves of precipitation that push through this weekend into early next week.

AVIATION.../Until 18Z Friday/

Flight conditions look to primarily remain in the MVFR/IFR category range through the TAF period. Conditions may lower into the LIFR category with any FG encountered this morning or tonight. SFC winds remain light & LLWS stays benign through the period.

MARINE

Outside Waters: Winds continue their downward trend Thursday as ridging passes over the Gulf waters with seas 7 and 9 ft by. Winds and seas look to rise Thursday night into Friday, especially from Cape Edgecombe south, as a low is projected to pass through the southern Gulf and towards Haida Gwaii. For the weekend, a forecasted low near the northern Gulf will give the eastern Gulf waters 25 to 35kts and a building southwesterly swell, with seas becoming 15+ ft by Sunday. These elevated winds and seas will last into next week.

Inside waters: Winds continue their diminishing trend across the inner channels Thursday as ridging sets up in the Gulf. However, winds are expected to begin to increase Thursday night and Friday morning across the southern inner channels with a system passing south of the panhandle near Haida Gwaii, with brief northerly/easterly outflow developing to the north. Southerly winds return by Friday morning but Friday night, northerly flow returns to Lynn Canal. Speeds in the inner channels pick up to 20 to 25 kts by Friday night with the weekend seeing 25 to 35 kts.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Storm Watch from late Friday night through late Saturday night for AKZ318-319. MARINE...Small Craft Advisory for PKZ022-053-641>644-651-652-661>664-671- 672.