Tropical Storm Iselle formed over the Eastern North Pacific Ocean south of Baja California on Sunday morning. At 11:00 a.m. EDT on Sunday the center of Tropical Storm Iselle was located at latitude 15.3°N and longitude 114.2°W which put the center about 595 miles (955 km) south-southwest of the southern tip of Baja California. Iselle was moving toward the west-northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1003 mb.
A low pressure system over the Eastern North Pacific Ocean south of Baja California strengthened on Sunday morning and the U.S. National Hurricane Center designated the system as Tropical Storm Iselle.
The distribution of thunderstorms in Tropical Storm Iselle was asymmetrical. Thunderstorms were occurring in bands in the southern part of Iselle’s circulation. Bands in the northern side of Tropical Storm Iselle consisted primarily of showers and lower clouds. Storms near the center of Iselle generated upper level divergence that pumped mass away to the south and west of the tropical storm. The removal of mass caused the surface pressure to decrease.
Wind to tropical storm force extended out 105 miles (165 km) from the center of Tropical Storm Iselle.
Tropical Storm Iselle will move through an environment that will be somewhat favorable for intensification during the next 24 hours. Iselle will move over water where the Sea Surface Temperatures are near 29°C It will move under the southeastern part of an upper level ridge that is south of Baja California. The upper level ridge will produce northeasterly winds that will blow toward the top of Iselle’s circulation. Those winds will cause moderate vertical wind shear. The moderate vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification. Tropical Storm Estelle could intensify during the next 24 hours.
Tropical Storm Iselle will move around the southwestern part of a high pressure system that is over the Eastern North Pacific Ocean. The high pressure system will steer Iselle toward the northwest during the next 24 hours. On its anticipate track, Tropical Storm Iselle will remain far to the southwest of Baja California.
Elsewhere, Tropical Storm Moke was passing south of the Big Island of Hawaii and Tropical Storm Lala was spinning far to the northwest of Hawaii.
At 11:00 a.m. EDT on Sunday the center of Tropical Storm Moke was located at latitude 15.2°N and longitude 155.0°W which put the center about 310 miles (500 km) south of Hilo, Hawaii. Moke was moving toward the west at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1002 mb.
At 11:00 a.m. EDT on Sunday the center of Tropical Storm Lala was located at latitude 32.1°N and longitude 173.9°W which put the center about 365 miles (590 km) northeast of Kure Atoll. Lala was moving toward the west-northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 988 mb.
