UPDATE 8:30 a.m. Friday:
A National Weather Service forecaster said Friday morning that a storm likely to hit some Aleutian islands this weekend will generate stronger winds and higher seas on the Pacific side of the islands.
Seas are exceeding 60 feet and winds are up to 80 mph, said Anchorage-based forecaster Joe Wegman. As the storm enters the western and central Aleutians, seas will be greater than 40 feet, with winds up to about 60 mph, he said.
"There have been stronger storms in the past that have gone into the Bering Sea. In fact, just last year we had former typhoon Nuri," Wegman said. "I wouldn't say it's going to be the strongest ever, but it's certainly going to be a very powerful storm nonetheless."
A storm over the Bering Sea this weekend will bring high seas and winds of nearly hurricane force to the Aleutian Islands, while northern areas of the state will experience harsh wind chill temperatures, forecasters said Thursday.
The U.S. Coast Guard said Wednesday night that it had stationed an MH-65 Dauphin helicopter from Air Station Kodiak aboard the cutter Mellon, in preparation for any rescue operations that may be required during the storm.
"Our highest priority is protecting the safety of life at sea," Capt. Diane Durham, the Coast Guard 17th District's chief of response, said in the statement. "We are encouraging all mariners to monitor National Weather Service reports and take appropriate safety precautions, such as pulling into a safe harbor or taking shelter in the lee of an island, in order to safeguard their crews."
The National Weather Service's Alaska conditions map early Thursday showed waters west of Nome and Bethel under heavy freezing spray advisories through Friday, with winds up to 30 mph and seas up to 10 feet.
Joe Wegman, an Anchorage-based forecaster with the weather service, said forecasters have been developing more precise forecasts of the storm's effects headed into the weekend.
"The weather models have been pretty consistent on having a storm move into the Bering, and a very strong one too," Wegman said.
Wegman said the system, currently over the western Pacific Ocean, is expected to move northward into the western Bering Sea over the next few days. In the process, it will be strengthened Friday night by a contrast between Siberian polar air and warmer air from the equator -- as well as a wind pattern at higher altitudes.
"It's close to Japan right now, but right now it's nowhere near the strength we expect it to be when it enters the Bering," Wegman said. "Essentially, we're just bringing in a lot of ingredients that are favorable for the development of storms all at the same time."
The storm's distance from Alaska's coast is expected to mitigate coastal flooding concerns, Wegman said. Both the western and central Aleutian Islands, however, can expect 60-knot winds -- just below the weather service's 65-knot threshold for declaring them hurricane-force -- during the storm's passage.
"For the Central Aleutians we are forecasting winds of 60 knots, and seas of 50 feet on Sunday on the Pacific side," Wegman said.
In Interior Alaska, windchill advisories took effect at 6 a.m. Thursday for the northern Brooks Range and the Beaufort Sea coast. The advisories call for wind chill down to 55 degrees below zero, amid relatively modest winds from 15 to 20 mph.
Bob Fischer, the lead forecaster at the weather service's Fairbanks office, said prevailing winds were forecasted to carry the wind chill deep into the state.
"We have some very cold air over the Interior Arctic Slope," Fischer said. "We're looking for southwest winds along the coast area bringing that cold air inland -- we're expecting that to cause the wind chill temperatures."
Fischer said the advisories, which are slated to end at 6 a.m. Friday, aren't likely to be extended.
"The cold air will remain in place, but we're expecting the winds to become light," Fischer said. "That will reduce the wind chill."
By weekend's end, the Bering storm should reduce in intensity as well, Wegman said.
"The storm is expected to begin weakening once it reaches the central Bering, and that will be on Sunday," Wegman said. "Even after it begins weakening, it will be a very strong storm."