Tropical Cyclone Emnati Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Emnati strengthened to the equivalent of a major hurricane east of Madagascar on Sunday morning. At 10:00 a.m. EST on Sunday the center of Tropical Cyclone Emnati was located at latitude 17.3°S and longitude 55.5°E which put it about 220 miles (355 km) north-northwest of St. Denis, La Reunion. Emnati was moving toward the west-southwest at 8 m.p.h. (15 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 945 mb.

Tropical Cyclone Emnati rapidly intensified to the equivalent of a major hurricane east of Madagascar on Sunday morning. A circular eye with a diameter of 14 miles (22 km) was at the center of Emnati’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Emnati. Storms near the core generated strong upper level divergence that pumped mass away from the tropical cyclone. Microwave satellite images showed that the inner end of a rainband was wrapping around the existing eye and eyewall. Concentric eyewalls could be forming and an eyewall replacement cycle could be starting.

The potential start of an eyewall replacement cycle caused the size of the circulation around Tropical Cyclone Emnati to increase. Winds to hurricane/typhoon force extended out 40 miles (65 km) from the center of Emnati’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Emnati was 22.0. The Hurricane Size Index (HSI) was 17.8 and the Hurricane Wind Intensity Size Index (HWISI) was 39.8. Tropical Cyclone Emnati was capable of causing regional major damage.

Tropical Cyclone Emnati will move through an environment favorable for intensification during the next 24 hours. Emnati will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the northern side of an upper level ridge over the Southwest Indian Ocean. The ridge will produce easterly winds that will blow toward the top of Emnati’s circulation. The winds in the lower atmosphere are also blowing from the east and there will be little vertical wind shear. Even though Tropical Cyclone Emnati will be in an environment favorable for intensification, if an eyewall replace cycle occurs Emnati will weaken when the current eyewall dissipates. Tropical Cyclone Emanti could eventually strengthen again after the eyewall replacement cycle is completed.

Tropical Cyclone Emnati will move north of a high pressure system over the Southwest Indian Ocean. The high pressure system will steer Emnati toward the west-southwest during the next 24 hours. On its anticipated track Tropical Cyclone Emanti will move away from La Reunion on Sunday. Tropical Cyclone Emnati could reach the east coast of Madagascar in 48 hours. Emnati could be the equivalent of a major hurricane when it reaches Madagascar. Tropical Cyclone Emnati will bring strong destructive winds and locally heavy rain to southern Madagascar. Heavy rain is likely to cause flash floods in some locations. Emanti will also cause a significant storm surge along the southeast coast of Madagascar.