Tropical Cyclone Horacio passed south of Diego Garcia as it moved over the South Indian Ocean on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Horacio was located at latitude 17.0°S and longitude 71.3°E which put the center about 675 miles (1095 km) south of Diego Garcia.  Horacio was moving toward the west at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 998 mb.

Tropical Cyclone Horacio struggled to intensify on Saturday.  Horatio was under the northern side of an upper level ridge that was over the South Indian Ocean.  The upper level ridge produced easterly winds that blew toward the top of Horacio’s circulation.  Those winds caused moderate vertical wind shear.  The wind shear inhibited intensification.

The easterly winds in the upper levels and the vertical wind shear also affected the distribution of thunderstorms in Tropical Cyclone Horacio.  Thunderstorms were occurring in bands in the western and northern parts of Horacio’s circulation.  Bands in the eastern and southern sides of Tropical Cyclone Horacio consisted primarily of showers and lower clouds.

The vertical wind shear also affected the distribution of wind speeds in Tropical Cyclone Horacio.  Winds to tropical storm force extended out 100 miles (160 km) in the southern half of Horacio’s circulation.  Winds to tropical storm force extended out 60 miles (95 km) in the northern half of Tropical Cyclone Horacio.

Tropical Cyclone Horacio will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Horacio will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the northern part of an upper level ridge that is over the South Indian Ocean.  The upper level ridge will continue to produce easterly winds that will blow toward the top of Horacio’s circulation.  Those winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but it may not be enough to prevent intensification.  Tropical Cyclone Horacio is likely to intensify during the next 24 hours. Horacio is likely to strengthen to the equivalent of a hurricane/typhoon by Monday.

Tropical Cyclone Horacio will move around the northern part of a high pressure system that is over the South Indian Ocean.  The high pressure system will steer Horatio toward the west-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Horacio will move closer to Rodrigues.  Horacio could approach Rodrigues in 36 hours.

Tropical Cyclone Horacio developed over the South Indian Ocean south of Diego Garcia on Thursday night.  At 10:00 a.m. EST on Friday the center of Tropical Cyclone Horacio was located at latitude 15.5°S and longitude 75.3°E which put the center about 610 miles (985 km) south-southeast of Diego Garcia.  Horacio was moving toward the south-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 999 mb.

A low pressure system over the South Indian Ocean south of Diego Garcia strengthened on Thursday night and Meteo France La Reunion designated the system as Tropical Cyclone Horacio.

The circulation around Tropical Cyclone Horacio was organizing quickly on Friday morning.  Thunderstorms were forming near the center of Horatio’s circulation.  Thunderstorms were also developing in bands revolving around the center of Tropical Cyclone Horacio.  Storms near the center of Horacio generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Cyclone Horacio was fairly large.  Winds to tropical storm force extended out 175 miles (280 km) from the center of Horacio’s circulation.

Tropical Cyclone Horacio will move through an environment favorable for intensification during the next 24 hours.  Horacio will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the northern part of an upper level ridge that is over the South Indian Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Horacio’s circulation.  Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification.  Tropical Cyclone Horacio will intensify during the next 24 hours.  Horacio is likely to strengthen to the equivalent of a hurricane/typhoon during the weekend.

Tropical Cyclone Horacio will move toward the northern part of a high pressure system that is over the South Indian Ocean.  The high pressure system will steer Horacio toward the west-southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Horacio will move toward Rodrigues.  Horacio could approach Rodrigues in three days.