FZAK30 PAFC 241753 ICOAFC Sea Ice Outlook for Western and Arctic Alaskan Coastal Waters National Weather Service Anchorage Alaska 952 AM AKDT Thursday 24 April 2025 ...APRIL 2025 MONTHLY SEA ICE OUTLOOK... April continued the trend from late-February through March of spurts of northerly flow as the storm track for the beginning of the month was predominately from the north Pacific into the Gulf of Alaska and southern Mainland. A very cold upper-level low pressure sank southward from the Chukchi Sea into the Bering Sea, reinforcing the anchor for the overall longwave pattern and prevailing storm track into the Gulf of Alaska. However, in April, lengthening days and increasing sun angles makes it increasingly difficult to grow ice. While there has been new growth in polynyas further north in the Bering Sea, the ice pack has mainly advected southward as is, with strips of ice coming off of the main pack. The warmer sea surface temperatures along the ice edge in the Bering Sea are melting the strips of ice as they come off of the main pack. The break-up outlook for this season remains tricky due to the rapid retreat then regrowth. The edge has come so far south over the last month that the analog years have changed completely from last month’s outlook. The edge is closest to 2024 and 2023, which gives some confidence in choosing break-up dates to have recent analogs. The other was 2015. As we look forward into the heart of break-up, ENSO-neutral conditions have already taken hold over the equatorial Pacific Ocean, which should favor general climatology of the last 10 years. ...BREAK-UP OUTLOOK FOR THE BERING SEA... Within Kuskokwim Bay, sea ice is expected to no longer be shorefast during the second week of May. Sea ice concentration for the entire Bay is open water at this point. When the shorefast ice breaks up there may be a period of three tenths again. Sea ice free conditions are expected during the second week of May. Etolin Strait sea ice is expected to reach three-tenths during the second week of May and be sea ice free during the third week of May. For Etolin Strait to Cape Romanzof, ice will no longer be shorefast around mid-May. Three-tenths coverage is expected during the third week of May. Ice free conditions are expected during the last week of May. For Cape Romanzof to Nunam Iqua, ice is no longer expected to be shorefast in during the last week of May. Three-tenths coverage is expected in during the last week of May. Ice free conditions are expected during the first week of June. For Nunam Iqua to Unalakleet, ice is no longer expected to be shorefast during the last week of May. Three-tenths concentration is expected during the first week of June. Ice free or open conditions are expected during the second week of June. For Shaktoolik, ice coverage is going to depend on the overall melt of Norton Sound. Currently, open water exists off of the shorefast ice, but favorable winds from the south or west will bring pack ice back to the area. Ice free conditions are expected during the third week of May. For Norton Bay, ice is no longer expected to be shorefast during the last week of May. Three-tenths of ice is expected during the last week of May. Ice free conditions are possible in late May but more likely during the first week of June. For Golovin Bay, sea ice is no longer expected to be shorefast during the last week of May. Three-tenths concentration of ice expected during the last week of May. Ice free conditions are not expected until the first week of June. For the Nome area, ice is no longer expected to be shorefast in late- May. Three-tenths coverage of ice is expected during the last week of May. Ice free conditions are expected during the first week of June. For Norton Sound, three-tenths coverage is expected during the first half of June. Ice free conditions are expected in mid-June. For Port Clarence, ice will no longer be shorefast during the first half of June. Three tenths coverage is expected around mid-June. Ice free conditions are expected mid-June. For the Bering Sea south of 60N, ice free conditions are expected during the second week of May. South of Saint Lawrence Island, ice free conditions are expected during the first half of June. From St. Lawrence Island to the Bering Strait, three tenths coverage is expected around mid-June. The Being Strait to 20 nm N/S of Center Line, is expected to be ice free during the second half of June. The Bering Sea will be ice free during late-June. ...BREAK-UP OUTLOOK FOR THE CHUKCHI SEA... For Wales to Espenberg, ice is no longer expected to be shorefast during the first half of June. Three tenths coverage is expected in the second half of June. Open water is expected by the end of June. For Kotzebue Sound, ice is no longer expected to be shorefast in early-June. Three tenths coverage is expected around mid-June. Open water is possible during the second half of June, but more likely in during the first week of July. For Cape Krusenstern to Point Hope, ice is no longer expected to be shorefast during the first half of June. Three-tenths coverage is expected during mid-June. Open water is possible during the last week of June, but more likely during the first week of July. For Point Hope to Icy Cape, West to 170W, three-tenths coverage is expected in during the second half of June. For Point Hope to Wainwright, ice is no longer expected to be shorefast around mid-June. Three tenths coverage is possible by the during the last week of June, but more likely into the first week of July. Open water is expected around mid-July. For Wainwright to Point Barrow ice is no longer expected to be shorefast during the the last week of June. Three tenths coverage is possible by the last week of July, but more likely into August. ...BREAK-UP OUTLOOK FOR THE BEAUFORT SEA... For Point Barrow to Cape Halkett, ice could no longer be shorefast by the end of June, but is more likely in early-July. For Cape Halkett to Flaxman Island, ice could no longer be shorefast by the end of June but is more likely in early-July. For Flaxman Island to Demarcation Point Ice could no longer be shorefast by the end of June but is more likely during the first half of July. Three-tenths coverage is possible in late-July but more likely in August. $$ Lawson