Marine Weather and Tide Forecast for Chevak, AK

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Warming conditions expected through this weekend with highs in the mid or upper 60s with southerly flow over the Alaska Range and clearer skies possible.

- Gusty winds are possible for the Alaska Range passes beginning Saturday morning and last through the weekend. Wind gusts as high as 60 mph are possible, especially Sunday morning.

- Areas north of the Alaska Range are currently quite dry. Any showers that will occur within the next few days are likely to be isolated due to drier air in the lower levels.

West Coast and Western Interior...

- Warming temperatures are expected the next few days, with highs rising into the mid to upper 50s and lows 60s across the Western Interior and the Interior Seward Peninsula.

- Generally dry conditions are expected for the next few days with only scattered showers possible for portions of the YK Delta and Seward Peninsula. Chances for precipitation will be more likely on Saturday for the YK Delta.

North Slope and Brooks Range..

- High temperatures on the North Slope will range from the mid 20s to the lower 30s through the weekend, potentially reaching around 40 in the Southwestern Brooks Range.

- Mainly dry conditions expected to prevail across the region for the next several days.

FORECAST ANALYSIS AND DISCUSSION
The general pattern across Alaska remains in place with a large upper low located over the southern Bering Sea while ridging prevails from the southern Beaufort Sea through the Yukon and along the Canadian west coast. While this pattern tends to focus the most impactful weather to our south and west, there will be a few things to watch in the short term period that includes the upcoming weekend.

One subtle feature is an Arctic upper low that is currently traversing through the mean ridge from it's current position over the Yukon Flats enroute to a position along the Northwest Arctic Coast where it will become absorbed by the primary Bering trough.
This is a very dry feature which is temporarily preventing much moisture from moving north through the Interior, thus keeping any precipitation limited to scattered convection at best. By Sunday a rather strong 975 mb surface low will track into the southern Bering and manage to draw additional moisture northwards, allowing for better precip chances across the western zones including the YK Delta, Seward Penn and portions of the Western Interior.

Further east strong southerly flow will become focused perpendicular to the Alaska Range. As the upper low over the Bering sends shortwave energy north over the Alaska Range, models show a 50 knot jet streak at 700 mb which is close to mountain top level. This will begin to produce very strong winds through the passes with the orientation of the flow favoring Windy pass for the strongest winds. This will also set up a decent Chinook event for the Tanana Valley north of the range further dying the boundary layer while enhancing temps, all of which will lead to an enhanced fire weather threat across part of the middle Tanana Valley.



FIRE WEATHER
The upper-level pattern is a bit messy this afternoon, with the relatively weak features producing generally benign weather across our area this afternoon. However, we will be transitioning into a pattern which is more impactful, particularly for the Interior.

Through the rest of the day Friday, winds should be light but occasionally gusty as they mix down in the evening. In the Interior, winds will generally be out of the northeast, turning northerly in the Central and Eastern Interior and northwesterly into Delta Junction. Farther west, winds will be easterly. Chances for precipitation are near zero in the Interior where dry upper- level air is allowing evening cumulus to develop. In the western half of Alaska, there are slightly better chances for showers this evening and even a stray thunderstorm or two in the Seward Peninsula. Temperatures will peak in the 60s and the dry weather will put relative humidities in the Interior in the 20s.

This weekend, the low over the Aleutians will press up against a ridge building over Canada, resulting in a pattern that is directing southerly flow across the Alaska Range and into the Interior. The largest impact will be strong winds through the Alaska Range passes, particularly Isabel Pass and up towards Delta Junction. In fact, a Red Flag Warning has been issued for Delta Junction for Saturday and Sunday for wind gusts up to 50 mph and RHs in the low 20s. Winds will strengthen slightly in the rest of the Interior, predominantly easterly with stronger gusts in the evening. Temperatures will get up into in the mid 60s for most spots in the Interior and we may even see a peak into 70 in the Yukon Flats on Sunday. Relative humidities may get into the teens in Interior Valleys and the Yukon Flats. Conditions will fair slightly better in the Western Interior where moisture advection is higher and chances for showers are more likely. Thunderstorms are not expected this weekend, apart from along the AlCan border in the higher terrain around Fortymile Country on Saturday.

HYDROLOGY

Yukon River: The ice jam at the Yuki river, which had remained in place for nearly two and a half days, finally released Thursday afternoon sending a strong surge of ice and water downstream toward Galena.
The release triggered rapid downstream breakup with rapidly changing conditions along the river. The initial surge carried large intact sheets through Bishop Rock, which has reduced the threat of an ice jam forming there. Late Thursday evening the main ice run was seen moving steadily past Galena.

At Koyukuk, ice was moving steadily past the community while water levels continued to rise and back up the Koyukuk River, however no significant flood has been reported as of this morning.

Water levels are expected to continue rising in both Galena and Koyukuk as large volumes of water previously locked up behind the ice jam continues to move downstream. The River Watch team reports that water levels behind the previous jam are comparable to the 2023 breakup season. Thus it is expected that minor flooding will remain possible in Galena and Koyukuk in the coming days. Thus flood watches will remain in effect for these areas.

Further upstream, high water continues to move downstream from Stevens Village through Tanana.

Chena River: The Chena River continues to respond to warmer temperatures with higher elevation snowmelt leading to rivers running higher than normal, but likely remaining below action stage.

Additional Information: Visit www.weather.gov/aprfc for the latest hydro information.

Please report observed flooding to local emergency services, law enforcement, or to the National Weather Service when you can do so safely.

.EXTENDED FORECAST DAYS 4-7...(Tuesday through Friday)
The persistent upper low over the Bering will still be in place to start the period. However the blocking ridge extending from the high Arctic into the Yukon will be breaking down a bit with ridging shifting a bit farther east through the period. This should allow for troughing to extend further east across southern and central Alaska with additional storm centers making their way into the Gulf late in the period. This pattern will continue to support a generally southerly flow pattern for the central and eastern parts of the state with occasional shortwaves tracking north into the region. Strongest surface winds will remain across the West Coast closer to the main storm center. In addition east winds will be picking up again along the Arctic Coastline as the Arctic surface high will be re-strengthening as well. As for precipitation chances, they will remain the highest from the YK Delta into the Seward Penn thanks to proximity to the low. However southerly transport of moisture will allow for scattered convection throughout the Interior on a near daily basis as energy pivots north through the main trough.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES
AK...Flood Watch for AKZ829.
PK...Small Craft Advisory for PKZ801-850.
Brisk Wind Advisory for PKZ815-861.