textproduct: Fairbanks

SYNOPSIS

A broad area of low pressure continues over the western portions of the state. This will allow for multiple waves of precipitation to move across the Central/Western Interior and West Coast over the next couple of days. Meanwhile, the positioning of the trough has set up southerly flow across the Interior. This will allow for warm, dry, and windy conditions to persist through the middle portions of the week. However, another surface low will work its way into the northern Gulf of Alaska, stationing itself in a favorable setup for some wrap around precipitation into the Interior starting Wednesday night. In addition, the southerly flow through coming over the Alaska Range will allow for additional chances for Wind Advisory Criteria winds through the Alaska Range passes today and Thursday. High water along the Lower Yukon River has caused flooding impacts in Grayling, Holy Cross, and Russian Mission. Flood Warnings have been issued for these communities.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Isolated to scattered showers continue across the Interior, today, with a non-zero chance of embedded thunderstorms amongst the showers. - Best chances for thunderstorms today will be across the middle portions of the Central Interior.

- Another round of gusty southerly winds are expected through the Alaska Range passes today. Wind gusts through Isabel and Windy Pass are expected to be between 45 and 55 mph. A Wind Advisory is in effect for Isabel Pass and Delta Junction.

- Mostly dry conditions expected across the Interior interrupted by occasional rain showers. A Red Flag Warning has been issued for Delta Junction. - Seasonably warm temperatures are expected to continue across the Interior through much of the week.

West Coast and Western Interior... - Gusty S-SE winds are expected across the West Coast this afternoon with an upper-level shortwave passage.

- Thunderstorm chances for this afternoon shift north over the central portions of the Western Interior.

- Showery conditions are expected along the Lower Yukon and Yukon Delta regions throughout the week. Heavier showers are expected today and Thursday. These showers will be mostly rain, especially nearer the Western Interior, but some periods of snow and light wintry mix are possible near St. Lawrence Island and the Bering Strait Coast.

North Slope and Brooks Range.. - Showery conditions are expected to continue along the southern portions of the Brooks Range today. Little to no precipitation is expected across the North Slope.

- Chilly temperatures persist with highs in the 20s and lows in the teens along the North Slope. A gradient of temperatures across the Brooks Range with highs in the 50s to near 60 along the southern slopes and low 40s for the northern slopes.

- Breezy northeasterly winds along the Western North Slope weaken slightly and shift more easterly. E to ENE winds 15 to 25 mph are expected across the Arctic Coast through Wednesday.

- Low clouds and areas of fog persist across the Arctic Coast and will likely remain through much of the week, especially along the Eastern Arctic Coast.

FORECAST ANALYSIS AND DISCUSSION

Not much change to the overall forecast as persistence continues to hold on strong. The main driver of the forecast continues to be the Bering low that has slowly been filling in since yesterday afternoon. Farther north, high pressure continues to linger over the Arctic. This has resulted in a decent pressure gradient across the state, with the strongest winds occurring around peak heating. High pressure is expected to continue over the Arctic for much of the forecast period, allowing the easterly winds, fog, and cooler conditions to continue across the North Slope.

A shortwave continues to make its way, NW, toward the Norton Sound. Guidance shows the surface low to move around St. Lawrence Island and get wrapped back in to the flow of the trough over the Bering. As this happens, another low will be moving east along the Aleutians. Models show this low to gradually weaken as it progress, reaching Bristol Bay coast sometime Thursday afternoon. This set-up will allow for the broad troughing to continue across northern Alaska, which will result in isolated showers and non- zero chances for thunderstorms through the end of the week. Compared to the previous low, this one is able to progress farther east, which will be a better set up for potential gap winds as bands of energy move across the Alaska Range over the coming days. The strongest gap winds are expected to be today and Thursday. To add on, latest model runs have shown the low to fill in slower with each run, which could help keep the surface gradient tighter as it moves towards Bristol Bay. This will play more of a role for the increased wind potential on Thursday. Meanwhile, another low will move into the northern Gulf of Alaska by Wednesday afternoon. Models are showing the potential for the low to set up between the 150 and 140 longitude lines, allowing the potential for wrap around precipitation into some portions of the Interior. Nonetheless, the prevailing southerly flow over the Alaska Range could keep areas north of the range drier with the downsloping. This, in combination with the previously mentioned gap winds, could bring Red Flag conditions through Isabel Pass and Delta Junction today and Thursday when the winds are strongest.

With this next low showing the potential to progress farther east than the previous one, this will allow for easterly flow to return across portions of the Northern Interior and Yukon Flats by Thursday. These will be the best chances for isolated thunderstorms on Thursday as models are showing cape values to be around 150 J/kg, which is more than enough to get a pop-up thunderstorm with the help of topographical forcing. This will spread across to other portions of the Interior by the end of the week as a series of lows continue to move into the northern Gulf of Alaska.

FIRE WEATHER

The overall pattern remains mostly the same through much of the week with a low in the Bering Sea and ridging over Western Canada. This pattern will continue to support broad southerly flow across the region. Downsloping effects will work to keep most of the central and eastern Interior dry and warm with a few afternoon rain showers possible. Accumulations should remain light with localized higher amounts expected in southwest Alaska and where thunderstorms are present. Although chances are low, a non-zero chance for lightning is possible this afternoon across portions central portions of the Western and Central Interior. Thunderstorm chances largely diminish after today with a slight chance for very isolated thunderstorm development later this week across the Interior, Brooks Range, and Yukon Flats. Expect high temperatures in the 60s and lows in the 40s through the week, with min RH values ranging between 20 to 30% in the central and eastern Interior and 30 to 40% in the western Interior.

The greatest area of fire concern this week will be near Delta Junction as strong southerly gap winds develop Tuesday and Thursday through Isabel Pass. Sustained winds between 20 to 30 mph gusting as high as 55 mph are possible this afternoon with similar conditions expected to develop again Thursday as the pressure gradient over the Alaska Range restrengthens later this week. A Red Flag Warning was issued for Delta Junction beginning this afternoon through late Tuesday night for a combination of dry fuels, strong winds, and dry air with min RHs values near 25%. We will continue to monitor the situation near Delta Junction on Thursday as conditions are expected to near critical fire weather criteria once again.

HYDROLOGY

Yukon River: The breakup front on the Yukon has passed Russian Mission. As of Monday morning, an ice jam was reported downstream of Russian Mission that has caused water levels to rise. A Flood Warning remains in effect. Water remains high on the Yukon upriver from the breakup front due to snowmelt and the Yuki Ice Jam release. Water has inundated the road to the airport at Grayling and Holy Cross. Flood warnings have been issued.

High water is expected to continue until the ice jam releases. Water levels will likely rise near the jam as higher water levels continue to move downstream towards the jam. Water levels are continuing to drop at Galena and beginning to drop at Koyukuk. No additional water level rises are expected at Koyukuk or Galena. As of 1:50pm AKDT, Monday, the river gauge at Galena shows the water levels dropping down to 122.6 ft which is below the minor flooding stage.

Buckland River: Water levels are falling and the river upstream of Buckland is open. Open leads have been reported downstream of Buckland and flooding is no longer expected.

Chena: 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

To start the extended time frame on Friday, a front will have pushed well into the Interior ahead of a low in southwestern Alaska. This will bring another chance for scattered thunderstorms across a good portion of the Interior on Friday. High pressure in the Arctic will allow for persistent easterly winds to blow along the Arctic coast and northerly winds along the West Coast through the weekend. Along the front in the Northern Interior and in the Seward Peninsula/Kotzebue Sound area will be a band of numerous rain showers, with scattered showers in the Southern Interior in its wake. Periods of heavy snowfall will also be possible in the Alaska Range, with gap winds diminishing by mid to late Friday. As the front crosses the Brooks Range by Saturday morning, snow will decrease in the Alaska Range, with scattered showers continuing on the north side, including on the North Slope. Generally warm conditions will persist throughout the period south of the Brooks Range, with highs in the 50s and 60s. The West Coast will likely see highs in the 30s and 40s, with 20s and 30s on the North Slope. Additional showers will be possible across Northern Alaska early next week ahead of another potential system in southwestern Alaska.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ837-849. Flood Watch for AKZ826-830. Red Flag Warning for AKZ937. PK...Small Craft Advisory for PKZ801-850. Small Craft Advisory for PKZ812. Brisk Wind Advisory for PKZ814. Brisk Wind Advisory for PKZ815. Small Craft Advisory for PKZ816. Small Craft Advisory for PKZ817. Small Craft Advisory for PKZ854. Brisk Wind Advisory for PKZ860.