Marine Weather and Tide Forecast for Old Harbor, AK

.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days 1 through 3)...

Key Messages:

* Scattered showers persist tonight over Southwest and the northeastern Alaska Peninsula as a front continues to move through.

* Showers and southwesterly winds as high as storm-force (with higher gusts) move through the Bering on Sunday and reaches the Southwest Coast by Sunday evening.

* A new Coastal Flood Advisory is in effect for the Kuskokwim Delta (Kipnuk, Toksook Bay, Kwigillingok, and Kongiganak) Sunday evening into Monday for minor-moderate flooding.

* A Wind Advisory is in effect for the Kuskokwim Delta for 30 to 40 mph winds and 55 mph gusts, as the push of strong winds approach late Sunday into Monday.

Discussion:

Tonight, a front advances inland across Southwest Alaska, with the core of strongest rainfall over the eastern Bristol Bay and Lower Kuskokwim Valley. West of the front, conditions have cleared for much of the eastern Aleutians, southern Alaska Peninsula and places northward up to the western portions of the Southwest Coast. The front continues eastward and slowly weakens as it pushes into higher pressure. Most showers over interior portions of Southwest Alaska look to taper off by Sunday morning, with highest chances of precipitation lingering along the Alaska Range.
Some showers may move through the Kuskokwim Delta this evening and persist over the Kilbuck Mountains through tomorrow.

Focus shifts westward later this weekend and into the workweek as a series of lows look to track through the Bering. The first of these develops off the Kamchatka Peninsula today and moves into the western Bering by Sunday morning. This low continues northeast to the Seward Peninsula by Monday morning before rapidly dissipating. South of the low, rain and southwesterly gale-force winds are expected throughout the Bering, with showers and strong winds reaching the Kuskokwim Coast by Sunday evening. Wind gusts up to 55 mph are possible from the Kuskokwim Coast up to Bethel Sunday evening into Monday morning. As such, a Wind Advisory has been issued for the Kuskokwim Delta, in effect Sunday afternoon through Monday morning. Additionally, another round of coastal flooding is expected for the Kuskokwim Coast Sunday evening. A new Coastal Flood Advisory is in effect for the Kuskokwim Delta coast, with the water levels expected to reach up to 2 to 3 above the normal high tide line for Kipnuk. Kwigillingok is not expected to see as relatively high of water levels or impacts from flooding, but will still see waters 1 to 2 feet above the normal highest tide line. Widespread precipitation across Southwest Alaska Sunday night into Monday becomes more scattered throughout Monday morning then tapers off Monday afternoon.

Another low moves north from the Pacific and crosses the western Aleutians Monday morning, bringing more showers and gale to storm- force sustained winds, and hurricane-force gusts to the western Bering. This low looks to be a bit stronger and tracks further west and north compared to Sunday's low. By Monday afternoon, the low begins to push a front eastward through the Aleutians and Bering. Southerly gale-force winds and showers will be seen along this front. Currently, this low is not expected to bring another round of flooding potential to the Southwest Coastline, but will maintain southwesterly flow into the area, potentially limiting the ability for flood waters from the Sunday/Monday system to recede quickly.

-CL

.LONG TERM FORECAST (Days 4 through 7: Wednesday through Saturday)...

The long term forecast continues to favor an unsettled weather pattern across much of Alaska as broad upper-level troughing becomes established over the state. Model guidance remains in fairly good agreement with the overall pattern, showing a series of upper-level lows moving across the Bering Sea and into mainland Alaska. However, differences remain regarding the strength, timing, and placement of individual disturbances, particularly toward the end of the period.

By Wednesday, an upper-level trough will continue digging southward across western Alaska as ridging over the Gulf weakens.
A more organized upper-level low is expected to move into western Alaska Wednesday into Thursday, bringing colder air and increasing chances for precipitation across Southwest Alaska. Rain will likely remain the primary precipitation type along coastal locations, while colder temperatures inland will support a mix of rain and snow, with snow becoming more likely across higher elevations and portions of the Kuskokwim. Meanwhile, Southcentral Alaska will begin to see increasing precipitation chances as the upper-level pattern becomes more amplified and disturbances move eastward.

Heading into Thursday and Friday, model guidance continues to indicate a more active pattern as a strong upper-level low develops over the Bering Sea and gradually shifts eastward. This system will help reinforce broad troughing across western Alaska, with additional shortwaves rotating around the larger circulation. Periods of precipitation and gusty winds will remain possible across the Aleutians, Bering Sea, and Southwest Alaska.
Farther east, an upperl-level low moving across the northern Gulf will maintain precipitation chances across Southcentral Alaska, particularly along coastal areas and the eastern Kenai Peninsula.
Colder air moving into the region may also support snow across higher elevations and some inland locations, although precipitation type will depend on how quickly colder air becomes established.

By Friday into Saturday,broad upper-level troughing looks to persist across much of Alaska as the Bering Sea low gradually weakens and additional disturbances move through the region. This will maintain an unsettled pattern across Southwest and Southcentral Alaska, with continued chances for precipitation.
The potential for colder air to spread farther south may increase snow chances across inland locations, while coastal areas will likely continue to see primarily rain or a rain and snow mix.
Additional shortwaves moving through the broader trough may also bring periods of gusty winds, particularly along coastal areas.

While model guidance remains in reasonable agreement with overall transition toward a more amplified troughing pattern, uncertainty increases toward the end of the week regarding the timing, strength, and placement of individual upper-level lows. These differences will play an important role in determining precipitation coverage, precipitation type, and where the strongest winds may develop.

LM


AVIATION

PANC...VFR conditions are expected to prevail through Sunday morning with the possibility of MVFR to IFR ceilings through the remainder of the period as chances for scattered showers increases. Overall winds are expected to remain light, but gusty Turnagain Arm winds may bend into the terminal at times resulting in wind gusts of 15-25 kt.