Near St. Lawrence Island
Sea ice along the northern coastline of St. Lawrence Island continued to break apart and destabilize during the past week. Shorefast ice remains along the northern coastline extending offshore up to 5 nautical miles. West of Savoonga, beyond the shorefast ice of the northern coast lies a polynya with open water to very open pack ice consisting of first year ice floes. Beyond the shorefast ice of the northern coast, east of Savoonga, there is close pack ice. Open water currently lies off the coast near Gambell with open pack ice drifting with the winds and ocean currents further offshore. Belts of ice are being pulled down past the east coast of the island with open to close pack ice. Rotting first year ice floes are currently drifting past the southeastern coastline of the island. These ice floes are riding low in the water and are expected to melt out rapidly in the coming week. West of Sekinak Lagoon on the south coast lies open water with very open pack ice drifting with the winds and ocean current further offshore.
Wales to Shishmaref
Some shorefast ice along the coast from Wales to Shishmaref has broken off in the past week. It still remains in place near Mugisitokiwik (stretching up to 9 nautical miles offshore) and Shishmaref (stretching approximately 5 nautical miles offshore). Beyond the shorefast ice from Mugisitokiwik to Ikpek lies a region of very open pack with first year floes, while beyond the shorefast ice from Ikpek to Shishmaref lies a region of close pack ice consisting of first year floes. There is also a giant floe off the coast of Ikpek that has broken off from the shorefast ice. A very narrow polynya with isolated first year ice floes has opened near the coastline, from approximately Shishmaref to Espenberg. Beyond the coastline from Tin City to Wales lies an area of open water with first year floes drifting past. Much of the eastern half of the Bering Strait is open water to open pack ice at this time, and the main ice pack in the southern Chukchi Sea continues to collapse with first year floes breaking apart and shifting.
From now through May 24th, we expect the shorefast ice along the northern coastline of St. Lawrence Island to continue to destabilize with mainly southerly to southwesterly wind flow. During this time the close pack ice will shift northward along the east coast of the island.
For the Wales to Shishmaref region we expect the outer edges of the shorefast ice to slowly continue to destabilize in the coming week. The close pack ice will drift southwestward along the shorefast ice through May 21st. Polynyas will continue to form off the shorefast ice edge as winds become southerly again on May 22nd.
Weather System/Wind Synopsis
Low pressure will move from the Alaska Peninsula on Friday, 20 May to north of the Bering Strait on 21 May. Another, weaker low-pressure system will move from Bristol Bay to Norton Sound on 22 May. High pressure will build over the southern Bering Sea starting 22 May, with low pressure over Chukotka. With these rapidly moving weather systems, wind directions will be variable and quickly changing. However, except for a brief period of south winds 20 to 30 mph (15 to 25 kt) through the Bering Strait late on 21 May, wind speeds will generally be 15 mph (13kt) or less. Starting 23 May, a prolonged period of south to southwest winds 15 to 25 mph (10 to 20 kt) is likely, with the potential for briefly higher winds through the Bering Strait.
Temperatures will generally remain warmer than normal for the next two weeks, except for a period of near-normal temperatures 21-23 May. During the period of 21-23 May, daytime temperatures are forecast in the 30s to low-40s, with overnight lows in the upper 20s. After that, daytime temperatures will generally be 40 to 50 with overnight lows in the 30s. The coolest temperatures throughout the next two weeks will be near St. Lawrence Island.