Tropical Storms Hernan and Iselle formed west of Mexico.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Hernan was located at latitude 19.1°N and longitude 106.2°W which put it about 95 miles (155 km) south-southwest of Cabo Corrientes, Mexico.  Hernan was moving toward the north-northwest at 5 m.p.h. (8 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 1001 mb.

The circulation around Tropical Storm Hernan was not well organized.  An upper level ridge over the southwestern U.S. and northern Mexico was producing northeasterly winds which were blowing toward the top of Hernan.  Those winds were causing strong vertical wind shear.  As a result of the shear, the stronger thunderstorms were occurring in bands in the southern part of the circulation.  Bands in the other parts of Tropical Storm Hernan consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 100 miles in the southern half of Hernan.  Winds in the northern half of the circulation were blowing at less than tropical storm force.

Tropical Storm Hernan will move through an environment unfavorable for intensification during the next several days.  Hernan will move over water where the Sea Surface Temperature is near 29°C.  So, there will be plenty of energy in the upper ocean to support intensification.  However, the upper level ridge will continue to cause strong vertical wind shear, which will inhibit potential intensification.  Tropical Storm Hernan is likely to weaken on Friday when it moves over colder water.  Hernan could approach the southern end of Baja California on Friday.

At 11:00 a.m. EDT on Thursday the center of Tropical Storm Iselle was located at latitude 17.0°N and longitude 115.8°W which put it about 560 miles (900 km) southwest of the southern tip of Baja California.  Iselles was moving toward the northeast at 5 m.p.h. (8 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 1001 mb.

The circulation around Tropical Storm Iselle was also not well organized.  It was being sheared by the same upper level ridge that was causing strong vertical wind shear over Tropical Storm Hernan.  Most of the thunderstorms in Iselle were also occurring in the southern half of the circulation.  Tropical storm force winds extended out 100 miles from the center in the southern half of Tropical Storm Iselle.  Iselle will also move through an environment unfavorable for intensification.