textproduct: Fairbanks

SYNOPSIS

Broad scale troughing persists over the state as a low pressure system in Bristol Bay gradually moves east into the Gulf of Alaska by Thursday. Scattered showers and isolated thunderstorms are possible through the weekend, with coverage expanding southward towards the Alaska Range. As high pressure builds over Siberia and the Canadian Yukon later this week, warmer and drier weather is expected across Northern Alaska.

KEY WEATHER MESSAGES

Central and Eastern Interior... - Isolated thunderstorms and scattered showers are expected to continue across most of the Interior throughout the week. The greatest chances for thunder will be in the higher terrain of the Central and Eastern Interior this afternoon, with coverage expanding to most of the Interior by Thursday.

- Southerly gap winds through the Alaska Range passes will continue this morning, with gusts up to 40 mph possible. Gusty winds are expected to subside by late morning.

- High temperatures will remain in the low to mid 60s through the weekend with a warming trend expected early next week.

West Coast and Western Interior... - Scattered showers and isolated afternoon thunderstorms continue across the Western Interior and parts of the Seward Peninsula this week. Showers and thunderstorm chances gradually decrease and become more isolated going into the weekend.

- Gusty north/northeast winds are expected to continue through the Bering Strait today through Friday with winds gradually weakening by Thursday. Gusts as high as 30 to 40 mph are possible.

- Temperatures will remain in the upper 50s to low 60s through the weekend before steadily increasing early next week.

- Patchy dense fog is possible across the West Coast each morning this week.

North Slope and Brooks Range... - Slightly cooler than normal temperatures continue across the North Slope with highs in the mid to upper 20s and lows in the upper teens.

- East/northeast winds will continue across the Arctic Coast this week with limited impacts expected. Winds shift towards the south/southwest by the late weekend.

- Low clouds and patchy fog are expected to persist across the North Slope through the week with gaps in the clouds becoming more common farther west. Clearer skies are possible this weekend into next week as winds weaken and offshore flow sets up along the coast.

FORECAST ANALYSIS AND DISCUSSION

For Wednesday through Friday night. Broad scale troughing continues over the state as a vertically stacked low sitting in Bristol Bay gradually moves east into the Gulf of Alaska. This system will work to keep scattered showers and isolated thunderstorm chances around through the weekend across much of Northern Alaska. Wetting rain chances are expected to remain low this afternoon as RH values drop into the 30% range across much of the region. As the low moves east, the pressure gradient over the Alaska Range weakens, allowing for winds through Isabel Pass to gradually dissipate through the afternoon. By Thursday, the low will have reached the Gulf of Alaska and pulled a large swath of moisture and shortwave energy south towards the Alaska Range. This will work to increase precipitation and thunderstorm chances over the Central/Eastern Interior Thursday and Friday afternoon.

By the end of the week, the two high pressure systems over Siberia and Canada will have strengthened enough to push the Gulf low farther southeast. As the Siberian high pushes inland form the west, gusty winds from the Lisburne Peninsula south towards the Bering Strait are expected to gradually weaken through the weekend. With broad scale ridging likely by early next week, warmer and drier weather may finally bring the first 70F day of the summer season.

FIRE WEATHER

As upper level troughing remains over Northern Alaska, scattered rain showers are expected to persist over the majority of the region. These showers gradually move southeast throughout the week as a Siberian high brings in upper level ridging from the west starting around Friday morning. This pattern change is expected to bring warmer and drier conditions to most of the region this weekend and into next week.

Isolated afternoon thunderstorms are likely for the Yukon Flats, most of the Interior, and Seward Peninsula this afternoon. By Thursday afternoon, isolated thunderstorm chances spread farther south to include the Alaska Range and Western YK Delta. These convective storms are expected to move south/southeast out of the region throughout the week and into the weekend. Southerly winds through the Alaska Range passes are expected to remain elevated through this afternoon, with gusts up to 50 mph possible through Isabel Pass. This afternoon is expected to be a relatively drier with min RH values in the mid to upper 20s percent range over the Upper Tanana Valley and portions of the Forty Mile Country. Increased moisture is expected across the area by Thursday afternoon with min RH values increasing into the 40s percent range by the weekend. Temperature-wise, highs remain in the low to mid 60s south of the Brooks Range. As upper level ridging arrives this weekend, models show the potential for highs to exceed 70F early next week across portions of the Central and Eastern Interior Valleys.

HYDROLOGY

Yukon River: River Watch reported that ice was able to move through Casey Channel and the South Mouth with relative ease. The remaining upstream ice is thinning quickly and will likely move through the area early this morning. Residents should still use caution near the banks as the ice run continues to be very dynamic and water levels can fluctuate quickly.

Flood warnings remain in effect for St. Mary's, Emmonak, and Alakanuk. A Flood Watch remains in effect for the Yukon Delta.

St. Mary's: At 840pm, flood waters continue to slowly recede. Due to the extensive high water and inundation, this process could take several days. Residents should use caution in and around areas that were flooded.

Emmonak: At 845pm, local observers report that the ice ran out quickly Tuesday evening with water levels dropping. However, the roads to the airport remain impassable by vehicle at this time. Given that there is little to no ice upstream in the Yukon, the flood threat is greatly diminishing and waters should continue to recede. Residents should use caution in and around high water.

Alakanuk: At 850pm, local observers report that the water levels have dropped 2 feet since Tuesday morning and are below bankfull throughout the village. The roads to the airport were covered with water as of 2pm Tuesday. River Watch observed the Alakanuk Slough was jammed and backing up at the mouth at roughly 5pm. However, given that there is very little to no ice upstream in the Yukon, the flood threat is greatly diminishing. Residents should continue to exercise caution near the ice chunks and high water.

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

Saturday through Tuesday. The long term forecast can be broken up into Friday/Saturday, and Sunday into early next week. Friday and Saturday see a continuation of the upper level low near the northern gulf with broad troughing across the state. While some uncertainty exists regarding the speed at which the low will move out, there is better concensus that the upper level low will dig south, bringing in ridging from both western Canada and near Siberia. Therefore, isolated daily showers and storms will continue to shift south as a warmer and drier pattern develops. This setup will be conducive for warming temperatures in the Interior ranging from the upper 60s to mid 70s for highs, with around a 50-60% likelihood of exceeding 70F by June 1st. Outside of the Interior, temperatures are also expected to broadly warm. On average in Fairbanks, our first 70F day is May 20th so while we are a bit behind average, we are expecting to be ahead of the record latest first 70F day which was set last year on June 11th. Overall, we are looking at a warmer and drier start to June across Northern Alaska as a ridge of high pressure establishes itself in the Bering and pushes the more favorable storm track down farther to our south.

Coastal Hazard Potential Days 3 and 4...None

AFG WATCHES/WARNINGS/ADVISORIES

AK...Wind Advisory for AKZ849. Flood Watch for AKZ825. PK...Small Craft Advisory for PKZ801. Small Craft Advisory for PKZ806-811-854. Brisk Wind Advisory for PKZ807-810-856. Small Craft Advisory for PKZ812-857. Small Craft Advisory for PKZ817. Small Craft Advisory for PKZ858.