Tropical Storm Lorenzo formed in the central tropical Atlantic at 5 a.m. EDT Monday, Oct. 13. At 11 a.m. EDT Monday, Lorenzo was located midway between the coast of Africa and the Lesser Antilles Islands, headed northwest at 16 mph (26 km/h). Lorenzo had top winds of 50 mph (85 km/h) and a central pressure of 1002 mb. Lorenzo is predicted to recurve to the north and northeast out to sea, peaking as a high-end tropical storm with 70 mph winds on Thursday. Lorenzo poses no threat to any land areas.
Lorenzo’s formation date of Oct. 13 comes close to the 1991-2020 average formation date of the season’s 12th named storm of Oct. 11. This pulls the 2025 Atlantic hurricane season to near-average status in three out of four categories, with 12 named storms, four hurricanes (Category 5 Erin, Category 4 Gabrielle, Category 5 Humberto, and Category 2 Imelda), three major hurricanes, and an accumulated cyclone energy, or ACE, index 91% of average. The 1991-2020 averages by this point in the season are 12.2 named storms, 5.9 hurricanes, and 2.7 major hurricanes. Typically, about 15% of hurricane season activity remains after October 13 (as measured by ACE index).
A rare location for a late-season storm
As documented by Michael Lowry today, it’s rare for a named storm to form this far east in the deep tropics (south of 20°N) this late in the hurricane season. This last occurred back in 2003 when both Nicholas and Peter formed very late (Oct. 13 and Dec., 7, respectively) far east over the Atlantic Main Development Region, an area typically reserved for August and September formations.
Lorenzo is the second Atlantic named storm in the past four days to form in an unusual location. On Thursday, Oct. 9, Subtropical Storm Karen formed while located at 44.5 degrees north, 33.0 degrees west, or about 545 miles northwest of the Azores. That made it the northernmost system in Atlantic history to be designated as a tropical or subtropical storm by the National Hurricane Center. Karen survived as a subtropical storm in its unlikely location for only 18 hours, being declared post-tropical by NHC at 5 p.m. EDT Friday.
The runner-up for northernmost named storm in the Atlantic behind Karen since NHC began naming subtropical storms in 2002 was Tropical Storm Grace, which developed northeast of the Azores on October 4, 2009, while at 41.2 degrees north and 20.3 degrees west. As reported by Michael Lowry, the HURDAT 2 database also includes a single entry for a hurricane on August 5, 1858, located at 45.0°N.
Keep an eye on the Caribbean next week
A tropical wave emerging from the west coast of Africa today is predicted to move west at 15-20 mph this week and arrive in the Lesser Antilles Islands around Monday, Oct. 20. As the disturbance approaches the islands, wind shear is predicted to be low enough to allow the wave to develop into a tropical cyclone, as predicted by the Monday morning runs of the GFS and European models and many of their ensemble members. While it’s too early to be concerned about a specific threat, the model signal is strong enough that residents of the Caribbean islands should be paying attention to future forecasts of this disturbance. As of 8 a.m. EDT Monday, NHC had not yet highlighted the wave in their Tropical Weather Outlook.
Bob Henson contributed to this post.
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