Tag Archives: Tropical Cyclone Iggy

Tropical Cyclone Grant Moves Northeast of Rodrigues

Tropical Cyclone Grant moved northeast of Rodrigues over the South Indian Ocean on Friday.  At 10:00 a.m. EST on Friday the center of Tropical Cyclone Grant was located at latitude 15.2°S and longitude 66.4°E which put the center about 375 miles (605 km) north-northeast of Rodrigues.  Grant was moving toward the west-northwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1000 mb.

Tropical Cyclone Grant was maintaining its intensity on Friday morning.  An upper level ridge over the South Indian Ocean continued to produce easterly winds that blew toward the top of Grant’s circulation.  Those winds were causing strong vertical wind shear.  The strong vertical wind shear was affecting the structure of Tropical Cyclone Grant.  Thunderstorms were still occurring in bands in the western half of Grant’s circulation.  Bands in the eastern half of Grant consisted primarily of showers and lower clouds.  Storms near the center of Grant still generated upper level divergence that pumped mass away to the west of the tropical cyclone. However, the removal of mass in the upper levels was about the same as the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure remained nearly constant.

The vertical wind shear was also affecting the distribution of wind speeds in Tropical Cyclone Grant.  Winds to tropical storm force extended out 70 miles (110 km) in the western side of Grant’s circulation.  The winds in the eastern side of Tropical Cyclone Grant were blowing at less that tropical storm force.

Tropical Cyclone Grant will move through an environment that will be marginally favorable for intensification during the next 24 hours.  Grant 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 over the South Indian Ocean.  The upper level ridge will continue to produce easterly winds that will blow toward the top of Grant’s circulation.  Those winds will cause moderate vertical wind shear.  The moderate wind shear will inhibit intensification.  Tropical Cyclone Grant is likely to maintain its intensity during the next 24 hours.

Tropical Cyclone Grant will move around the northern side of a high pressure system over the South Indian  Ocean. The high pressure system will steer Grant toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Grant will pass north of Rodrigues on Saturday.  Grant will pass north of Mauritius and La Reunion on Monday.  Tropical Cyclone Grant could approach the east coast of Madagascar on Tuesday.

Elsewhere over the South Indian Ocean, Tropical Cyclone Iggy weakened south-southeast of Christmas Island.  At 10:00 a.m. EST on Friday the center of Tropical Cyclone Iggy was located at latitude 16.8°S and longitude 1086°E which put the center about 455 miles (735 km) south-southeast of Christmas Island.  Iggy was moving toward the southwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1003 mb.

Tropical Cyclone Grant Weakens

Tropical Cyclone Grant weakened as it moved over the South Indian Ocean northeast of Rodrigues on Thursday.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Grant was located at latitude 15.7°S and longitude 67.1°E which put the center about 370 miles (600 km) northeast of Rodrigues.  Grant was moving toward the west-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 997 mb.

Tropical Cyclone Grant weakened rapidly on Thursday.  An upper level ridge over the South Indian Ocean produced easterly winds that blew toward the top of Grant’s circulation.  Those winds caused strong vertical wind shear.  The strong wind shear caused Tropical Cyclone Grant to weaken rapidly.

The strong vertical wind shear also affected the structure of Tropical Cyclone Grant.  Thunderstorms were still occurring in bands in the western half of Grant’s circulation.  Bands in the eastern half of Grant consisted primarily of showers and lower clouds.  Storms near the center of Grant still generated upper level divergence that pumped mass away to the west of the tropical cyclone.  However, the removal of mass in the upper levels was much less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased rapidly on Thursday.

The circulation around Tropical Cyclone Grant was small.  Winds to tropical storm force extended out 100 miles (160 km) from the center of Grant’s circulation.

Tropical Cyclone Grant will move through an environment that will be marginally favorable for intensification during the next 24 hours.  Grant 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 over the South Indian Ocean.  The upper level ridge will continue to produce easterly winds that will blow toward the top of Grant’s circulation.  Those winds will cause moderate vertical wind shear.  The moderate wind shear will inhibit intensification.  Tropical Cyclone Grant is likely to maintain its intensity during the next 24 hours.

Tropical Cyclone Grant will move around the northern side of a high pressure system over the South Indian Ocean.  The high pressure system will steer Grant toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Grant will pass north of Rodrigues on Saturday.  Grant will pass north of Mauritius and La Reunion on Monday.

Elsewhere over the South Indian Ocean, Tropical Cyclone Iggy moved farther away from Christmas Island.  At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Iggy was located at latitude 15.4°S and longitude 106.5°E which put the center about 425 miles (685 km) south-southeast of Christmas Island.  Iggy was moving toward the south-southeast at 8 m.p.h. (13 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 1000 mb.

Tropical Cyclone Iggy Forms Southeast of Christmas Island

Tropical Cyclone Iggy formed over the South Indian Ocean southeast of Christmas Island on Wednesday evening.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Iggy was located at latitude 12.5°S and longitude 107.9°E which put the center about 200 miles (320 km) southeast of Christmas Island.  Iggy was moving toward the south-southeast at 11 m.p.h. (17 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 998 mb.

A low pressure system over the South Indian Ocean southeast of Diego Garcia strengthened on Wednesday evening and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Iggy.

More thunderstorms developed near the center of Tropical Cyclone Iggy on Wednesday evening.  Thunderstorms also formed in bands revolving around the center of Iggy’s circulation.  Storms near the center of Iggy began to generate 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 Iggy was small.  Winds to tropical storm force extended out 80 miles (130 km) from the center of Iggy’s circulation.

Tropical Cyclone Iggy will move through an environment favorable for intensification during the next 24 hours.  Iggy will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southwestern part of an upper level ridge that is northwest of Australia.  The upper level ridge will produce northwesterly winds that will blow toward the top of Iggy’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Cyclone Iggy will intensify during the next 24 hours.

Tropical Cyclone Iggy will move around the southwestern side of a high pressure system that is northwest of Australia.  The high pressure system will steer Iggy toward the southeast during the next 24 hours.  On its anticipated track, Tropical Cyclone Iggy will move farther away from Christmas Island.

Elsewhere over the South Indian Ocean, Tropical Cyclone Grant weakened as it moved farther away from Diego Garcia.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Grant was located at latitude 16.2°S and longitude 68.5°E which put the center about 670 miles (1080 km) south-southwest of Diego Garcia.  Grant was moving toward the west-southwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 984 mb.