textproduct: Juneau

SYNOPSIS

Key Messages:

- An active pattern continues as multiple lows and associated fronts push into the panhandle through the week, bringing multiple rounds of strong winds and heavy rain across SE AK.

- Wind Advisories remain in effect for Yakutat and Sitka through Monday evening. Wind gusts up to 40 mph at Sitka, up to 55 mph at Yakutat.

- Winter Storm Warning continues through Monday evening for the Haines Highway near Haines Customs, with snowfall totals of 8 to 12 inches.

LONG TERM

/Thursday through the weekend/

Thursday morning sees the beginning of a stronger atmospheric river move into the area. Some rather impressive dynamics look to be associated with this storm, with strong initial warm air advection, and relatively cold air advecting eastward. These ingredients coupled with sea surface temperatures still around the mid 50s means that the environment leans more towards the convective. Furthermore, a strong jet aloft with plenty of divergence behind the warm front sets the stage for meso vertices forming along the front. These cause a number of issues: timing, location, and intensity of rainfall and highest winds can shift drastically. Individual model runs tend to struggle with these environments, with run to run consistency of both the GFS and EC inconclusive on individual features. Ensemble guidance provides a clue on the location of highest wind speeds and rainfall however. At this point, the southern half of the panhandle has the highest likelihood of longer duration, heavier rainfall. Looking towards the weekend, there is roughly a 60-40 split of active weather continuing and a stronger low passing south respectively. If active weather continues, then generally southerly winds will accompany mostly rain for the panhandle. For the low passing south, this would invite stronger, downsloping northerlies, which would dry out the panhandle and bring cooler temperatures overnight.

AVIATION

/through Tuesday afternoon/ No significant changes from 18z issuance. VFR conditions ongoing across the panhandle this morning with ceilings AoA 3500ft and visbys generally greater than 6SM, however a strong low continues to spin off shore in the Gulf with its attendant front and moderate to heavy rainfall pushing inland. Conditions will continue to deteriorate through the afternoon to general MVFR to low-end VFR as this low tracks NW towards Anchorage. Main impact for our area will be the strong surface wind gusts 30 to 40kts and LLWS up to 50kts across the coastal terminals from Yakutat southward to Klawock, and over to Ketchikan through the evening. For the Icy Strait terminals, Gustavus and Juneau, thinking periods of stronger gusts up to 30 kts will continue through the evening. Winds will gradually diminish through 03z to 06z this evening for terminals other than Yakutat as the low pushes NW, holding on at Yakutat through 12z.

By 09z tomorrow morning, another low pushes along the SEAK coast with front pushing into the southern panhandle, so expecting a brief lull this evening followed by yet another round of strong wind gusts for Klawock and Ketchikan with gusts up to 30 to 35 kt from 09z through 18z Tuesday morning.

MARINE

Outside: As of Monday afternoon, an impressive 954mb Storm Force low is dominating the gulf, with coastal buoys reporting building seas of 20 to 25 ft as of 1300 AKST. Fresh seas will continue to grow Monday as the main front moves north, with deep water wave heights reaching 30 to 40 ft along much of our northern coast. Tuesday an active storm track continues with multiple storm force lows impacting the eastern Gulf through Wednesday, driving storm force winds and seas of 20 to 25 ft. For folks looking to make moves across the Gulf from Cross Sound to PWS, at this time winds and seas look to diminish to more reasonable levels starting late Wednesday. Keep an eye on the storm force low currently forecasted to undercut the Gulf Thursday into the weekend, driving easterly winds across the Gulf. While our forecast, and confidence, is that this system will head toward Haida Gwaii, there are a few model outliers that want to bring this system further north.

Inside: Conditions continue to be unfavorable for the inner channels as multiple storm force lows move across Southeast through Wednesday. Simply put, expect a series of fronts to bring sustained winds up to strong breezes, with localized areas of gale force conditions, diminishing, and coming back. Dont get lulled out by any lighter winds as another front is likely moving in soon. Thursday winds will subside to below strong breezes for much of the inner channels, bringing a short break. Friday a storm force low is forecasted to undercut the Gulf, driving northerly outflow through the central and northern inner channels. Major north-to-south passages will likely see northerly fresh to strong breezes with Lynn Canal and Taku seeing a few hours of near-gale force conditions. For Dixon, southern Clarence and Revilla, another round of more easterly near-gale, to gale force, conditions are likely.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Wind Advisory until 5 AM AKST Tuesday for AKZ317. Winter Storm Warning until 6 PM AKST this evening for AKZ319. Wind Advisory until 9 PM AKST this evening for AKZ323. Wind Advisory from 6 AM to noon AKST Tuesday for AKZ323. Wind Advisory from midnight tonight to noon AKST Tuesday for AKZ328-330-332. MARINE...Storm Warning for PKZ642>644-651-652-663-664-671-672. Gale Warning for PKZ032-033-036-053-641-661-662. Small Craft Advisory for PKZ011-013-021-022-031-034-035.