Marine Weather and Tide Forecast for Thorne Bay, AK

SYNOPSIS...

Key Messages:

- Dry weather continues through the remainder of Friday.

- A front arriving on Saturday brings periods of rain and wind, especially to the northern and central panhandle. Drier weather will linger in the south.

- Periods of moderate to heavy rain expected for Sunday and Monday as a stronger system pushes across the entire panhandle.

- Slow drying trend from N to S next week; with widespread warm weather and drier conditions possible as we approach the weekend.

SHORT TERM...
Quiet weather comes to an end through the day on Saturday as a gale force front arrives in the northern gulf, ahead of a plume of moisture arriving on Sunday and Monday which will bring periods of widespread rainfall across SE AK.

Skies have largely cleared across the area, as offshore flow has eroded away what was left of a marine layer earlier this morning.
Aside from scattered cumulus clouds, along with a few broken decks for locations like Gastineau Channel. Expect the remainder of Friday to be similarly pleasant.

This situation will come to an end through Saturday as a gale force front moves into the northern gulf. Already, satellite imagery depicts the front and its associated low strengthening south of Kodiak, even as they swiftly move north. ASCAT wind passes are indicating the ongoing development of a band of gale force winds, which will impact the northern gulf Saturday evening.
As the front moves up, drier weather early Saturday morning gives way to rain and windy conditions, mainly for areas north of Sumner Strait with rain and wind especially prevalent along the NE Gulf Coast. The front will rapidly weaken as it tries to push inland, and think that much of the south/central panhandle will see little to no rain from this initial push. A significantly stronger plume of moisture will take aim Saturday night into Sunday at the northern Gulf Coast (specifically Yakutat), before moving E through the day on Monday across the panhandle. Operational guidance has fallen into better agreement on the the plume of moisture, bringing it initially into Yakutat late Saturday night before veering east into the rest of SE AK on Monday. Upwards of 2-4 inches of rain are likely to fall for Yakutat proper, with 1-2 inches of rain for the northern and central panhandle, and up to 1-1.5 inches inches for the south. While rainfall amounts are impressive for the dry season, they remain relatively lackluster when compared to stronger fall systems, and most locations are unlikely to break even 1 year Atmospheric Return Intervals (ARIs).
Beyond Sunday, the jet stream looks set to take up a relatively zonal flow across the far southern panhandle through the first half of the week, paving the way for additional shortwaves to bring in more precipitation. For additional information, see the long term forecast discussion.

Temperatures beyond Friday are likely to remain on the moderate side for the central and northern panhandle through early next week, with highs in the 50s and 60s for most locations.
Temperatures in the southern panhandle by contrast will be in the 60s and 70s, as drier weather and the potential for continuing breaks in the clouds remain until the second system sweeps eastward Sunday and Monday.

LONG TERM
/Monday through Friday/
After the heaviest rain passes through the area with the front Sunday, rain chances will decrease through the day Monday for the Northern Panhandle. With onshore flow across Southeast Alaska, there will be at least some rain chances for the area through next Friday.

Monday, high pressure will develop in the Gulf, and it will begin a drying and warming trend. By Friday, high temperatures look to approach 70 for the Northern Panhandle.

Tuesday, with the jet stream across southern portions of the area, there is potential for a low pressure system to develop. If this low can develop, it will increase wind speeds and rain chances for areas generally south of Fredrick Sound. As of now, ensembles keep rain chances fairly low for the Southern Panhandle. Confidence in this low pressure forming is fairly low, but it is a situation worth monitoring.

AVIATION
/Through 06z Sunday/
VFR conditions and light winds continue to rule the aviation weather across the panhandle this evening. Though signs of change are starting to creep in. A high cloud layer is starting to sweep the area ahead of the front that will be arriving Saturday morning. Expect rain to start up along the outer coast from Cape Decision northwestward as early as 12z and spreading inland across the N half of the panhandle through the morning. Lowest conditions for vis and ceilings will be along the outer coast from around Cross Sound NW to Cape Suckling with mainly ceiling lowering to around 2500 ft or so with some isolated lower areas. Not much wind associated with this front with most of the wind staying offshore though some gusts to 20 to 25 kt could be observed along the outer coast mid morning. The front will push through during the day Saturday with a period improving conditions for the north (to VFR for areas that did have lower conditions) toward evening. However another round of rain will be incoming for the north (especially areas W of Cape Fairweather)
late Saturday night with vis and ceilings dropping into MVFR and possible IFR due to heavier rain rates. Southern panhandle (south of Sumner Strait) will mainly stay VFR through all of this.

MARINE...
Outside (Eastern Gulf): For the weekend, gale force winds along the northern coast, fresh seas as high as 20 ft, and heavy rain are the main threats.

Further detail: For Friday afternoon, winds are light across the coast, with sea state dominated by southerly swell 17 seconds at 3 feet. Winds will continue to turn southeast in response to an approaching low; the mighty tug Arctic Titan is always showing SE winds near Cape St. Elias Friday morning. Currently, this system of interest is near 50N 152W and moving north, with ASCAT/OSCAT Satellite wind passes highlighting gale force easterly winds on the northern flank. Southeast winds continue to build along our coast; anticipate near-gale force to strong breezes by Saturday morning with seas building to 10 to 14 ft.

These winds will ebb a bit Saturday afternoon, don't let this lull you into a false sense of security. Winds will ramp up quickly Saturday night, with gale force winds expected to start sometime near 12 AM to 6 AM Sunday morning, with the heaviest winds west of the Fairweather Grounds to Cape St. Elias. There could be localized areas of storm force conditions for a brief period of time just south of Cape Suckling. Wave guidance has struggled with significant wave heights Sunday; keeping things simple, expect short period fresh seas of at least 17 ft to as high as 20 ft near Cape St. Elias. Again, the heaviest conditions will be near Cape St. Elias and east toward the Fairweather Grounds. For folks south of Cross Sound, especially along the coast of PoW, expect winds of fresh to strong breezes and seas of 9 to 12 ft. Winds and seas begin to relax Monday.

Inside (Inner Channels): Winds slowly ramp up Saturday, reaching peak intensity Sunday.

Further detail: For the inside, sea breezes are the main threat Friday afternoon, but winds look lighter than what we have seen the previous few days. Moving through the weekend, winds will become southerly as a gale force low moves into the gulf, pulling the winds up and out of the Panhandle. For this surface pressure regime, the main problem areas Saturday look to be Chatham Strait, Peril Strait, and Icy Strait, with the potential to see winds of at least moderate breezes by Saturday afternoon. For the remainder of the region, there will likely be much less wind until Sunday as the low begins to jump ashore, bringing widespread winds of moderate to fresh breezes across the inside.

A note on Glacier Bay for Sunday: Mariners navigating the upper arms of Glacier Bay Sunday should be aware of an occluding front moving over the region. Anticipate southeasterly to build Sunday before this front moves over, which could bring pretty intense southerly winds to inlets exposed to the south like Reid Inlet.

AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...None.
MARINE...Gale Warning for PKZ651-652-664-671-672.
Small Craft Advisory for PKZ022-053-641>644-661>663.