Tropical Cyclone Horatio 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 Horatio 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.  Horatio 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 Horatio 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 Horatio’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 Horatio.  Thunderstorms were occurring in bands in the western and northern parts of Horatio’s circulation.  Bands in the eastern and southern sides of Tropical Cyclone Horatio consisted primarily of showers and lower clouds.

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

Tropical Cyclone Horatio will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Horatio 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 Horatio’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 Horatio is likely to intensify during the next 24 hours. Horatio is likely to strengthen to the equivalent of a hurricane/typhoon by Monday.

Tropical Cyclone Horatio 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 Horatio will move closer to Rodrigues.  Horatio could approach Rodrigues in 36 hours.

Tropical Cyclone Horatio 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 Horatio 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.  Horatio 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 Horatio.

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

Tropical Cyclone Horatio will move through an environment favorable for intensification during the next 24 hours.  Horatio 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 Horatio’s circulation.  Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification.  Tropical Cyclone Horatio will intensify during the next 24 hours.  Horatio is likely to strengthen to the equivalent of a hurricane/typhoon during the weekend.

Tropical Cyclone Horatio will move toward 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 Horatio will move toward Rodrigues.  Horatio could approach Rodrigues in three days.