Marine Weather and Tide Forecast for Valdez, AK

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

The Bering Sea, Aleutian Islands, and coastal Southwest Alaska are currently under the influence of two low pressure systems: one near Saint Matthew Island in the Northern Bering Sea, and one just south of the Alaska Peninsula in the North Pacific.
Meanwhile, high pressure is bringing clearer skies and warmer temperatures to interior Southwest Alaska.

For the Bering Sea, Aleutian Islands, and Southwest coastline, expect more active weather to persist through tomorrow afternoon, especially around the Alaska Peninsula. Mariners can expect some gales south of the Alaska Peninsula tonight, and the Pacific side of the peninsula can expect moderate to heavy rain along the front. The low weakens and exits south through Monday morning, bringing a reprieve through mid-week. By Wednesday afternoon, another North Pacific low begins to approach the Western and Central Aleutians. Gale-force winds are possible, and the decent moisture advection associated with this storm will likely bring moderate to heavy rain for the Central Aleutians.

For Southwest Alaska, hot and drier conditions continue, especially along Kuskokwim Valley. Temperatures will likely hit their peak tomorrow afternoon, with highs of 70-79 degrees for Kuskokwim Valley and highs of 60-69 degrees for most other parts of Southwest Alaska. These warmer surface temperatures will create a favorable environment for convection. Chances are high that we'll see some lightning by Tuesday over interior Southwest Alaska, with the most likely location being Kuskokwim Valley, Lime Village, and the northern reaches of Bristol Bay Borough.
However, the intensity and location of these thunderstorms continues to be a bit challenging to forecast. Models have generally been trending towards more organized upper level shortwaves moving east to west across Southwest Alaska. This could lead to greater cloud cover, making the environment less conducive to thunderstorms than currently forecast. In addition, the more organized upper level shortwaves could lead to the development of a weak surface low near Bristol Bay, which could advect in a more stable, maritime air mass that limits convection.
Given these trends, have cut back a bit on thunderstorm coverage with this latest forecast. Stay tuned as we continue to refine the forecast.

-Chen

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

For much of the long term, the operational models agree that the upper level ridge of high pressure that has been situated across interior Southcentral will remain steady-state and anchored in place, keeping temperatures generally warmer than average. The ridging will also keep an upper level easterly to northeasterly flow, allowing for more hazy skies from the Canadian wildfires, particularly for the Copper River Basin. This flow regime will be reinforced by a large upper level low across the Gulf of Alaska.
Afternoon and evening showers and thunderstorms will be likely confined to the northern Susitna Valley and Copper River Basin.
There is also fair agreement at the end of the long term of a large upper low in the Bering with smaller shortwaves rotating around its periphery that may help nudge and erode the ridge across Southcentral and force it to lift to the north. At the same time, for the Aleutian chain, there is average confidence of a large low pressure system moving out of the North Pacific and across the islands and retrograding to the northwest with its front becoming more elongated and pushing into the western Gulf of Alaska.

-AM


AVIATION

PANC...A stubborn marine layer crept into the airport Sunday morning into the early afternoon and brought in IFR ceilings. This marine layer will be the big forecast challenge for around the airport again overnight tonight and into Monday morning as the low-level flow will remain southwesterly up Cook Inlet and continue to push any marine stratus toward Anchorage. While there is a good chance that the low ceilings develop again tonight shortly after midnight, the presence of an upper level wave tomorrow and the increased vertical mixing due to that makes it more likely to clear out the low clouds earlier on Monday than what happened today. However, this marine layer and potential periods of lower ceilings may come and go over the next few days.