Marine Weather and Tide Forecast for Ketchikan, AK

PREV DISCUSSION
ISSUED AT 417 PM AKDT Wed Apr 15...

SYNOPSIS...

Key Messages:

- Clouds continue to move into the panhandle Wednesday evening before a band of precipitation moves into the northern and eventually central panhandle overnight

- A more organized frontal band will follow into the panhandle Thursday afternoon, continuing precipitation through Friday

- Showers/frontal bands continue to impact the panhandle through the weekend

SHORT TERM...

The forecast remains largely on track as mid-level clouds begin to push into the outer coast of the panhandle Wednesday afternoon.
This is preceding a band of precipitation associated with a shortwave trough that is expected to move from the west into the northern outer coast of the panhandle Wednesday evening. This band will continue to push into the northern and eventually parts of the central panhandle overnight, bringing light rainfall with short periods of snow for Yakutat and a rain/snow mix for Haines and Skagway. Behind this band, onshore flow will allow for developing showers in the gulf to push inland, continuing precipitation into Thursday morning. By early Thursday afternoon, a more organized frontal band is expected to reach the northeastern gulf coast and steadily push eastward into the northern panhandle and eventually the central panhandle by Thursday evening. The front is expected to reach the southern panhandle overnight into early Friday morning, with onshore flow pushing showers into the panhandle behind the front and continuing precipitation through Friday. The initial front on Thursday will bring around half an inch of rain to the northern panhandle and less than a quarter of an inch of rain to the central panhandle, though Yakutat may see closer to an inch of rain into Friday. With showers continuing Friday, the northern panhandle is expected to see anywhere between a half an inch to an inch of rain, with the southern panhandle seeing closer to a quarter to a half an inch.
Gusty winds are expected with the initial frontal bands, as well as with heavier showers behind them. Due to the relatively more northern track of this front, daytime high temperatures may not reach as high as they have been through the week, sitting around the mid 40s across the panhandle and only dropping to the mid 30s overnight into Friday.

LONG TERM...

Continuing from the short term discussion, moist onshore flow will persist through Friday with minimal breaks in the cloud deck for the northern panhandle as moisture funnels straight into the northern coast. Heading into Saturday morning, a broad, fast- moving low will jump up to around the 50th parallel north and send an occluding frontal band north into the far southeastern gulf.
Guidance is still somewhat split on how far north this front will go, but there is agreement that this will most likely scrape the southern portions of the panhandle. Combined with another frontal band from the remnants of the low in the northern gulf, a majority of the panhandle will be seeing around half an inch of precipitation through Saturday. Rainfall rates are expected to taper off through Sunday morning before another front moves along the northern gulf coast Sunday afternoon, forcing the lingering precipitation to shift southeast out of the panhandle. Uncertainty has somewhat improved from yesterday, with models coming more in line with a potential break in rainfall Sunday afternoon before the next frontal band moves into the northeast gulf coast.
Locations near Yakutat and along the northern gulf coast will see the most rainfall with this system on Sunday, but the frontal band is expected to spread into the rest of the panhandle by Monday.
Due to the northern track of this front, precipitation has the possibility of falling as snow overnight for northern locations near Yakutat and the northern highways. Gusty winds through the outer gulf waters and into the N/S oriented channels will be present with this frontal band. High temperatures look to slightly increase through the period, though low temperatures look to stay relatively consistent around mid 30s. Updates to the details of this late weekend system will be made as the period gets closer.

AVIATION...A disturbance on the north side of an area of high pressure is impacting southeast Alaska tonight and into the day Thursday. Conditions will steadily drop to MVFR and potentially IFR across northern portions of the Panhandle with showers. Places such as Petersburg, Wrangell, and Klawock could see some reduced visibilities tonight, but that should dissipate with daytime heating. During the day Thursday, some showery activity could make its way to the southern Alaska panhandle, and lead to some visibility impacts.

MARINE...

Outer Coastal Waters: Our northwesterly flow down the east side of the broad central Gulf of Alaska high pressure ridge has weakened a bit today, even going southwesterly for most of the eastern Gulf, as the ridge starts to essentially break down. By Thursday, we see weak low pressure forming at the top of the weakening ridge just south of Anchorage, moving slowly east across the northern Gulf through Thursday. We keep that light to moderate west to southwesterly flow over the eastern Gulf going tonight into Thursday, except for the northern Gulf zones from Icy Cape to Cape Suckling where we have posted Small Craft Advisories for Thursday when we see a tighter pressure gradient on the north side of the low center, with winds increasing to 25 kt and a small fetch area generating 8 ft seas.

Inner Channels: For today, we note an increased southerly flow down Lynn Canal to Portland Island where winds have picked up to 20 kt. We also see an uptick of southerly winds down parts of Stephens Passage and coming off the eastern Gulf of Alaska in Cross Sound.
As we progress through the evening, these areas of increased winds will drop off a bit and we will see a light southeasterly to easterly flow through morning, then another uptick in southerly winds tomorrow. To the south, a generally light southerly to easterly flow expected tonight into Thursday before we do see an uptick in east to southeasterly winds around 15 kt late Thursday through late week. Overall, marine impacts over the inside waters remain benign to minor.



AJK WATCHES/WARNINGS/ADVISORIES
PUBLIC...None.
MARINE...Small Craft Advisory for PKZ652-672.