textproduct: Juneau

SYNOPSIS

Key Messages:

-Moderate to heavy snow spreading over the panhandle Thursday with heaviest amounts expected along the outer coast.

-Northerly outflow intensifies as snow exits the region Friday, with strong gales developing for the northern inner channels by late Friday night ushering in colder temperatures for the weekend

LONG TERM

Friday the longwave trough begins to dig south, forming into a closed low along the western seaboard over the weekend. As this feature transits south, a very tight surface pressure gradient forms again between an arctic high in Canada and the relative warm waters of the Gulf, increasing the confidence that strong gale force outflow winds return for many inner channels through the weekend with the associated colder weather and freezing spray. For Juneau, a Taku wind event is becoming likely Saturday, driving gusts higher than 60 mph, with strong gusty winds persisting through the weekend.

Monday, outflow diminishes again as the Yukon high weakens and a new weather system moves in from the W. The possibility of precipitation returns for most areas by Tuesday with most of the areas likely still cold enough for it to be mostly snow.

AVIATION

VFR to MVFR CIGs continue this morning as the cloud cover continues to expand in coverage. Snow showers are expected to increase in coverage later this morning bringing CIGs and VIS down to around MVFR to IFR. It can't be ruled out though that some of the heavier snow showers could cause conditions to drop down to LIFR, especially along the outer coast as showers move onshore today. These conditions are expected to continue through the day today and into this evening.

MARINE

Outside: Waveheights will be on the rise by Thursday afternoon as a low approaches from the west. By Thursday night, waves over the outer coastal waters will reach 8-11 ft, and waves over the Gulf 15-20 ft. In the wake of the system on Friday, strengthening outflow winds will see gales and even storm force winds exiting out of outflow channels into the northern outer coastal waters from Cross Sound northward. Through the weekend, mariners should anticipate strong gale force northerly winds along major bays/inlets along the coast, with storm force NE winds likely near Dangerous River, bringing freezing spray and NE fresh seas.

Inside: Winds have largely diminished as the pressure gradient relaxes, opening a narrow wind through Thursday where lower winds and seas are in store for SE AK. a welcome break from the intense outflow conditions impacting the region over the last 48 hours. Anticipate winds largely less than 20 knots Thursday as snow moves across the Panhandle. Thursday night, winds begin to increase as a low transits south, with outflow winds building Friday. Mariners in Yakutat Bay will see gale force early Friday morning, with storm force in upper bay.

Expect gale force northerly winds in Lynn Canal by Friday afternoon and Taku Inlet, spreading south through the night. Gale to strong gale force will impact most areas along and north of Sumner Strait, with major inlets like the Stikine and Unuk seeing higher winds. Confidence is increasing for storm force conditions Sunday in Lynn Canal. These winds, along with cold temperatures, will generate large seas and freezing spray, complicating transits through our passages.

AJK WATCHES/WARNINGS/ADVISORIES

PUBLIC...Winter Storm Warning until 3 AM AKST Friday for AKZ317. Winter Weather Advisory until 3 AM AKST Friday for AKZ320-321- 324-325. Winter Storm Warning until 6 AM AKST Friday for AKZ322. Winter Storm Warning until 9 AM AKST Friday for AKZ323. Winter Weather Advisory from noon today to 6 AM AKST Friday for AKZ326-327-329. Winter Storm Warning from noon today to 9 AM AKST Friday for AKZ328. Winter Weather Advisory from 6 PM this evening to 9 AM AKST Friday for AKZ330-332. MARINE...Gale Warning for PKZ053-651. Small Craft Advisory for PKZ012-022-641>644-652-661>664-671-672.