Weekly Outlook for SIWO

Date: Thursday, May 15, 2025

St. Lawrence Island

Shorefast ice extends 0.5 mile (1 km) offshore of Gambell and Savoonga, and up to 5 miles (8 km) offshore between the two. Between Ataakas Camp and Camp Kulowiyi, shorefast ice extends up to 6 miles (12 km) offshore. Ice beyond the shorefast ice north of the island is very close to consolidated pack ice mostly consisting of small to big floes, with some isolated vast floes up to 30 miles (50 km) to 50 miles (80 km) offshore. 

East of the island, close pack ice consisting of medium to big floes extends up to 5 miles (8 km) to 10 miles (16 km) beyond the shorefast ice, then open pack ice consisting of big to vast floes extends up to 20 miles (32 km) east of the close pack ice. West of the island is a band of close pack ice consisting of small to medium floes extending up to 5 miles (8 km) offshore west of Gambell, then open water extends west off the close pack ice. To the south of the island is open water consisting of small floes and ice cakes beginning 15 miles (24 km) south of Siknik Training Camp and extending to the south. Generally sea ice free conditions extend off of the southwest portion of the island.

Shorefast ice extends 0.5 miles (1 km) from Wales to 18 miles (29 km) offshore Ikpek. Shorefast offshore Shishmaref extends 14 miles (23 km). Beyond the shorefast ice west and northwest of Wales is open water to very open pack ice consisting of small to big floes extending 6 miles (10 km) to 12 miles (19 km) to the northwest.

Shorefast ice extends between the islands. To the north, very close pack ice consisting of small to medium floes extends 1.5 miles (2.4 km) from the shorefast ice. Surrounding the islands is very open pack ice consisting of small to vast floes. Open water exists beyond 8 miles (13 km) east and 13 miles (21 km) west of Diomede.

Open water exists along the Nome coastline and extends up to 15 miles (24 km) to the southwest and 25 miles (40 km) to the south of Nome. Southwest of the open water is close pack ice consisting of medium to vast floes. Due south of the open water is very close pack ice consisting of medium to big floes. Ice free waters begin about 20 miles (32 km) southeast of Nome.

Shorefast ice extends up to 15 miles (16 km) southwest of Brevig Mission, then consolidated ice consisting of big to giant floes extends another 5 miles (8 km) beyond the shorefast ice. Open water exists about 6 miles (10 km) beyond the shorefast ice with widely scattered small to medium floes within the open water area. Beyond the open water is close pack ice consisting of medium to vast floes.

Sea ice will generally continue to drift south roughly 5-10 miles/day through Saturday (May 17). By Sunday (May 18), winds increase and sea ice will drift south/southeast roughly 10-15 miles/day. Sea ice across the Bering Sea will continue to gradually melt through the weekend.

Wind Synopsis

St. Lawrence Island/Wales/Diomede:

Winds over the St. Lawrence Island⁠–Wales/Diomede areas on Friday (May 16) will blow from the north at about 12 to 17 mph (10 to 15 kt) before weakening and shifting to the northwest-to-west during the afternoon and overnight hours. By Saturday afternoon, Wales/Diomede can expect northwest winds at about 12 to 17 mph (10 to 15 kt) while winds at St. Lawrence Island will remain light from the west. From Sunday through Wednesday, north to northwest winds will blow at 17 to 29 mph (15 to 25 kt) at Wales/Diomede and 17 to 23 mph (15 to 20 kt) at St. Lawrence Island. Thereafter (from Thursday onward), winds will potentially weaken, but there is very high uncertainty. There is a chance that a low moves into the Bering Sea from the southwest, which could lead to winds picking up into the 17 to 29 mph (15 to 25 kt) range from the southeast over St. Lawrence Island by Thursday afternoon and lasting into Friday (May 23).

Shishmaref area:

Winds at Shishmaref will generally blow from the east at around 6 to 12 mph (5 to 10 kt) from Friday (May 15) through Saturday morning before shifting to the west-to-northwest by Saturday afternoon. From Saturday afternoon through Wednesday morning, winds will blow from the north-to-northwest at around 12 to 17 mph (10 to 15 kt), with winds weakening to under 12 mph (10 kt) and turning to the west from Wednesday evening through Thursday morning. Depending on the trajectory of a potential low pressure system moving into the Bering Sea, winds could increase up to 12 to 23 mph (10 to 20 kt) from the south to southwest by Friday afternoon (May 23).

Nome/Brevig Mission area:

Winds in the Nome/Brevig Mission area will initially blow from the north at about 12 to 17 mph (10 to 15 kt) on Friday morning (May 16). In the afternoon, they will become light and variable but tend to blow more from the west to northwest at Nome and the north at Brevig Mission. Winds will remain weak at Nome but strengthen to 14 to 21 mph (12 to 18 kt) at Brevig Mission from Saturday night through Monday night before weakening to about 12 mph (10 kt). Winds will remain generally northerly at Brevig Mission around 12 mph (10 kt) and around 6 to 12 mph (5 to 10 kt) from the west at Nome through Friday morning. By Friday afternoon (May 23), there is a slight chance for winds to increase to 23 to 35 mph (20 to 30 kt) from the south at Brevig Mission and Nome ahead of another system which may enter the Bering.

At St. Lawrence Island and Wales/Diomede, highs will tend to rise into the lower-to-mid 30s, with lows falling into the mid-to-upper 20s. Shishmaref will mostly see highs rise into the mid-to-upper 30s each day, with lows falling into the upper teens to mid 20s. At Nome, highs will generally rise into the mid-to-upper 40s, with lows falling into the 30s. Brevig Mission will be a few degrees cooler than Nome but follow a similar temperature trend, with highs in the upper 30s to mid 40s and lows in the upper 20s and 30s.