textproduct: Fairbanks

SYNOPSIS

Most of the area south of the Brooks Range can expected highs in the upper 50s to low 60s today and Friday, with periodic showers in the Southern Interior. Easterly winds will continue on the Arctic coast, especially from Nuiqsut east, through tomorrow before finally weakening. As a low moves into the eastern Bering Sea this weekend, southeasterly winds will pick up across southeastern Alaska and some of the higher terrain in the Interior. Southerly winds will also be likely through the Alaska Range and its passes. This will allow for clearer, drier, and warmer conditions in the Interior Friday and Saturday, with many areas rising into the mid 60s or higher. Warm conditions with increasing showers are likely next week.

KEY WEATHER MESSAGES

Central and Eastern Interior...

- Easterly winds of 15 to 25 mph will be possible over higher terrain of the Central and Northeastern Interior and could last into Thursday night before weakening.

- Cooler temperatures will be possible today and Friday 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.

West Coast and Western Interior...

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

- It will be generally dry for the next few days with only scattered showers expected, with better chances for rain Friday and Saturday.

North Slope and Brooks Range...

- Gusty winds will continue across the Central and Eastern North Slope through tonight. Winds will be strongest along the Eastern Arctic Coast where winds could gust to over 35 mph. Areas of fog in the area which will reduce visibility in spots.

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

FORECAST ANALYSIS AND DISCUSSION

A 1024 mb high persists north of the Beaufort Sea this morning. It is fueling easterly gradient winds on the Arctic Coast, especially from Nuiqsut eastward, which could last the next couple days before the high finally shifts east and out of the area. Sky conditions are fairly clear from Utqiagvik east, but parts of the Western North Slope were under the cover of dense fog until around 4 AM, which could linger just offshore through the morning. The 500 mb reflection of the surface high in the Arctic has a narrow ridge extending southeastward across the Central/Western North Slope into the Eastern Interior. With a trough aloft over the southeastern Bering Sea and Gulf of Alaska, there is southeasterly flow across the southwestern half or so of Northern Alaska (from the AK Range north). This moist flow, combined with some supportive shortwave energy for extra support, will allow for showery activity in the Southern Interior to continue into the weekend. It will somewhat limit the extent of warm air in the Eastern Interior today and Friday with increasing cloud cover while also bringing the potential for isolated thunderstorms in the Fortymile Uplands and perhaps in parts of the Lower Yukon/ region where the lower levels can become thoroughly mixed.

By Friday morning, a low currently over the western Aleutians will cross into the eastern Aleutians with a central pressure in the low 980s or upper 970s mb. By Friday evening into Saturday morning, it will begin affecting southwestern Alaska with a strong southeasterly gradient wind and periods of rain. For the Fairbanks forecast area, this would be most notable in the Lower Yukon Valley, including the YK Delta, and at St. Lawrence Island. By Saturday afternoon, this vertically-stacked low and a ridge to its east will begin driving southerly winds across the Alaska Range, which will not only allow for gusty southerly gap winds in the passes but allow for some general warming and clearing in the Central/Eastern Interior. Highs in the mid or upper 60s will be possible in these areas through the weekend. Occasional showers will remain possible south of the Brooks Range during this time frame but will increase in coverage significantly Monday with isolated thunderstorms possible in the southern Interior as moisture makes a push inland with southwesterly flow and the low shifts north.

FIRE WEATHER

Upper level troughing in the southern Bering Sea continues to weaken and gradually move east into the Gulf of Alaska. As this troughing moves east, southeasterly flow over the state briefly weakens Thursday and Friday before reestablishing itself Saturday as troughing builds back in over the southern Bering Sea. With the return of southerly flow, temperatures quickly rise back into the mid to upper 60s across the Interior with the warmest temperatures expected across the Yukon Flats and Fortymile Country. Min RH values will see brief improvement Thursday before rapidly dropping to around 20% this weekend across the Interior Valleys, Yukon Flats, and Fortymile Country. Downsloping effects will keep precipitation chances to a minimum for much of the area with the exception of the Upper Tanana Valley where a few afternoon convective showers may develop on Thursday. A non-zero chance for lightning remains possible between Tok and Northway, but due to limited atmospheric lift and instability, chances remain unlikely. Marginal to light winds will continue through the weekend, with diurnally driven gusty winds possible in the afternoon hours. Southerly gap winds return to the Alaska Range passes Saturday as the pressure gradient tightens and southerly flow returns. Winds gusting as high as 40 to 50 mph is possible through Isabel Pass, but confidence remains low if the winds will reach Delta Junction. We will continue to monitor wind conditions over the next few days. Otherwise, relatively low fire risk is expected Thursday and Friday, with low to moderate threats possible this weekend.

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 Watch has been issued for Galena 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, contributing to flooding at Fort Yukon and Stevens Village. 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

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.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Flood Watch for AKZ829-833. PK...Brisk Wind Advisory for PKZ813. Gale Warning for PKZ814. Gale Warning for PKZ815. Brisk Wind Advisory for PKZ858. Brisk Wind Advisory for PKZ860. Brisk Wind Advisory for PKZ861.