Norma Rapidly Intensifies to a Major Hurricane

Hurricane Norma rapidly intensified to a major hurricane over the Eastern North Pacific Ocean on Thursday morning. At 8:00 a.m. EDT on Thursday the center of Hurricane Norma was located at latitude 17.0°N and longitude 107.5°W which put it about 430 miles (690 km) south-southeast of Cabo San Lucas, Mexico. Norma was moving toward the north at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 950 mb.

A Hurricane Watch was in effect for the portion of the coast from Todos Santos to Los Barriles, Mexico. The Hurricane Watch included Cabo San Lucas.

Hurricane Norma rapidly intensified to a major hurricane on Thursday morning. A circular eye with a diameter of 23 miles (37 km) was at the center of Norma’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Norma. Storms near the core generated strong upper level divergence that pumped mass away from the hurricane.

Winds to hurricane force extended out 25 miles (40 km) from the center of Hurricane Norma. Winds to tropical storm force extended out 150 miles (240 km) from the center of Norma’s circulation. The Hurricane Intensity Index (HII) for Hurricane Norma was 23.6. The Hurricane Size Index (HSI) was 10.6 and the Hurricane Wind Intensity Size Index (HWISI) was 34.2. Hurricane Norma was similar in size and intensity to Hurricane Dennis when Dennis hit Northwest Florida in 2005.

Hurricane Norma will move through an environment favorable for intensification during the next 12 hours. Norma will move over water where the Sea Surface Temperatures are near 29°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Norma could continue to intensify during the next 12 hours. An upper level trough west of Baja California will approach Norma later on Thursday. The upper level trough will produce southwesterly winds that will blow toward the top of Norma’s circulation. Those winds will cause the vertical wind shear to increase. Hurricane Norma will start to weaken when the wind shear increases.

Hurricane Norma will move around the western part of a high pressure system over Mexico. The high pressure system will steer Norma toward the north during the next 24 hours. On its anticipated track, Hurricane Norma could approach the southern end of Baja California on Friday night. Norma will bring strong winds and locally heavy rain to the southern end of Baja California. Heavy rain is likely to cause flash floods in some locations.