Ileana — 2024

A low pressure area that began as part of a tropical wave moved into the eastern Pacific and became a tropical depression at 1200 UTC 12 September about 140 nautical miles southwest of Cabo Corrientes, Mexico. The depression strengthened into Tropical Storm Ileana six hours later and moved north-northwestward just offshore the west-central coast of Mexico, passing very near Cabo Pulmo (southern Baja California Sur) around 0000 UTC 14 September. Ileana slowed in the southern Gulf of California and reached peak intensity late on 14 September, then wind shear removed its convection and the system degenerated to a remnant low by 0600 UTC 15 September. The remnant low tracked northwestward over the Gulf of California and dissipated near Bahía Kino, Sonora, just after 0000 UTC 17 September. Ileana did not make a definitive landfall; operationally it was thought to have crossed northern Sinaloa late on 14 September, but post-storm analysis shows the low‑level center remained over the Gulf of California and did not come ashore. The circulation passed within a few nautical miles of Isla de San Ignacio (near Topolobampo) and came very close (less than 10 n mi) to Cabo Pulmo in Baja California Sur while producing tropical-storm conditions along parts of the coast. The storm’s maximum sustained winds peaked at 45 knots (about 52 mph) from 1800 UTC 14 September to 0000 UTC 15 September, and the estimated minimum central pressure was 997 millibars at 0000 UTC 15 September. Topolobampo recorded a sustained wind of 44 kt (about 51 mph) with a 56‑kt gust at 2215 UTC 14 September, and Los Mochis airport reported sustained winds of 39 kt (about 45 mph) with a 42‑kt gust at 2345 UTC 14 September. Storm surge impacts were not large in the record, but coastal tropical-storm-force winds and gusts affected northern Sinaloa and extreme southern Baja California Sur. Rainfall totals of note include 9.51 inches (241.5 mm) at La Jaina, 9.49 inches (241.0 mm) at Gustavo Díaz Ordaz, and 7.68 inches (195.0 mm) at Guasave in Sinaloa; in Baja California Sur, San José del Cabo reported 8.61 inches (218.7 mm) and Boca del Salado 5.63 inches (143.0 mm). Gusts to 38 kt and 37 kt were measured at Cabo San Lucas and Cabo Pulmo, respectively. No direct fatalities were reported. Damage in Sinaloa and Baja California Sur included downed trees and transformers that caused power outages, closure of the port of Topolobampo, canceled flights at Los Mochis airport, overflow of the Corerepe Canal in Guasave that forced about 70 people to evacuate to a school, and flooding and landslides in San José del Cabo. About 200 people were reported in temporary shelters in La Paz and Los Cabos. Forecasts noted the possibility of formation more than a week beforehand, though confidence in genesis only rose within a day or two of formation. NHC track forecast errors were larger than recent 5‑year means at 12–48 hours and tended to place the center too far west (over southern Baja California Sur) compared with the actual near‑offshore track and subsequent north-northeast turn toward Sinaloa. Intensity forecasts were relatively skillful and several correctly anticipated Ileana’s modest peak intensity of 45 kt.