textproduct: Fairbanks

SYNOPSIS

Spring-time is here for portions of the West Coast and Interior as the snow continues to melt, river breakup progresses further downstream, and temperatures remain steadily in the 50s and 60s today and into the weekend. The North Slope, however, is expected to continue to see temperatures in the upper 20s and lower 30s. Scattered showers are expected today for Western Interior and Seward Peninsula today. As a low approaches from the Aleutian Islands, it will be joined by another low from the Gulf of Alaska. These two lows will bring lots of moisture resulting in relatively steady precipitation for the West Coast this weekend and isolated showers for the Interior with gusty winds through the Alaska Range passes.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Cooler temperatures will be possible today with increasing cloud cover and occasional showers possible. Warmer conditions will return this weekend with highs back 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 the large dewpoint depression.

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.

FORECAST ANALYSIS AND DISCUSSION

Weak, upper-level shortwave energy will be moving westward over the Yukon Flats today, bringing minimal impacts to the Interior besides the possibility of an isolated shower. This energy will continue to travel westward and eventually be pushed into the Chukchi Sea by the end of this weekend.

Our main weather-maker will be a low currently in the Bering Sea that will approach the YK Delta, but not quite make landfall. This low will bring more widespread showers for the YK Delta and Seward Peninsula Saturday. A secondary, more moist low will push northward from the Gulf of Alaska, bringing more precipitation to the southern portions of the state, along with the West Coast and Western Interior on Sunday. There is also a very slight, nonzero percent chance of a thunderstorm with these showers. Accompanying these showers will be gusty easterly/southerly winds for the YK Delta and Western Interior. Areas north of the Alaska Range currently have a large dewpoint depression, meaning any showers that fall will have to rise the dew point, likely resulting in the showers being isolated.

Due to the first low remaining in the Bering Sea throughout the weekend and an Eastern Arctic High, a pressure gradient will form over the state, especially over the Alaska Range. Upwards of 6 mb of a pressure gradient and southerly flow through the Alaska Range will create gusty winds this weekend, beginning Saturday morning with the strongest wind gusts as high as 60 mph possible Sunday morning.

FIRE WEATHER

Surface troughing continues to weaken in the Gulf of Alaska as it gradually moves east towards Canada. By Friday morning, a new low makes its way into the southeastern Bering Sea, helping to reestablish strong southerly flow over the state. As the low pushes further into the Alaska Peninsula, the surface pressure gradient over the Alaska Range tightens allowing for southerly gap winds to develop through passes. Winds gusting as high as 60 mph are possible Saturday morning through Sunday night through Isabel Pass, with gusts as high as 40 mph near Delta Junction. Across the Interior, winds are expected to remain mostly light with gusty winds possible during the afternoon hours, especially at higher elevations.

High temperatures across the Interior will rise into the lower to mid 60s through the weekend, with highs in the upper 40s and 50s with the chance of isolated areas seeing low 60s across the West Coast. Min RH values will remain dry around 20% this weekend across the Interior Valleys, Yukon Flats, and Fortymile Country with the Western Interior seeing values around 30%. Downsloping effects will keep precipitation chances to a minimum for the Central and Eastern Interior with scattered showers possible across the West Coast beginning Saturday morning through early next week. A non-zero chance for lightning is possible for portions of the Seward Peninsula Friday afternoon, but due to limited atmospheric lift and instability, chances remain unlikely.

Overall, expect low fire risks this weekend with moderate fire risks possible near Delta Junction beginning Saturday.

HYDROLOGY

Koyukuk River: The ice jam on the Koyukuk River downstream of Hughes flushed out Tuesday night, allowing water levels to fall back to near normal with no flooding observed in the community. The river was nearly ice free for at least 20 miles downstream of Hughes as well as upstream of the village.

Yukon River: An ice jam at the Yukon River breakup front, about 20 miles downstream of Ruby at the mouth of the Yuki River, has caused water levels to rise upstream in Ruby and the Big Eddy area. In the Big Eddy area, several structures were observed surrounded by floodwaters. In Ruby, water levels rose by several additional feet and were just below River Road. Downstream of the jam, water levels in Galena leveled off and slowly fell through the day. Little movement was observed in the intact ice sheets downstream to Bishop Rock. A Flood Warning has been issued for Galena through tonight for the potential for ice jam flooding from an ice jam downstream, including near Bishop Rock.

High water levels on the Porcupine River continues moving downstream along the Yukon River. Heavy runs of bank-to-bank ice were seen moving past Rampart all day Wednesday. A Flood Watch for potential snowmelt flooding in the Fort Yukon area and a Flood Warning for high water levels near Stevens Village remain in effect.

Chena River: The Chena River has begun to respond to warmer temperatures with increased snowmelt leading to rivers running higher and gages getting closer to or reaching 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

Monday through next Thursday. At the start of the extended forecast period, the pattern remains dominated by a strong upper level high over the Arctic Ocean. A strong upper level low in the Bering Sea is prevented from moving east towards the Gulf by a ridge extending over the Gulf and into the Yukon. All the while a weak upper level low that split off from a low far to the east in Canada slowly moves west across the state. Unfortunately this somewhat chaotic collection of upper level features complicates how the pattern will evolve early next week. Generally speaking most solutions favor higher pressure to the north and east and lower pressure to the south and west. The majority of the variance in the overall pattern lies south of the region, but there is enough variance to keep the forecast uncertain. Should the upper level high over the Arctic Ocean continue to remain steadfast in its position, then the weather over the majority of the region will remain similar to this past week with generally mild conditions and occasional bouts of showers. Should this high be pushed aside or weaken, the influence of the low in the Bering Sea will be felt further inland increasing east to northeasterly winds across the Interior and causing more widespread showers as well as possible thunderstorms. Shower and or thunderstorm chances will peak in areal coverage diurnally each afternoon, with light precipitation amounts expected as conditions remain predominantly dry. Temperatures will continue to hold steady through the extended forecast, with coldest conditions still holding north of the Brooks Range with near normal to above normal temperatures south of the Brooks Range.

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.