Tag Archives: SH01

Tropical Cyclone Rita Develops North of Vanuatu

Tropical Cyclone Rita developed over the South Pacific Ocean north of Vanuatu on Sunday.  At 4:00 p.m. EST on Sunday the center of Tropical Cyclone Rita was located at latitude 11.5°S and longitude 169.4°E which put it about 455 miles (730 km) north of Port Vila, Vanuatu.  Rita was moving toward the south-southeast at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 987 mb.

A center of circulation in an area of low pressure north of Vanuatu exhibited greater organization on Sunday and the system was designated Tropical Cyclone Rita.  Rita had a distinct low level center of circulation.  A band of showers and thunderstorms wrapped around the western and northern sides of the center.  Other rainbands were revolving around the center of circulation.  Storms near the center were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation.

Tropical Cyclone Rita will move through an environment relatively favorable for intensification during the next 24 hours.  Rita will move over water where the Sea Surface Temperature is near 28°C.  It will move under the western end of an upper level ridge over the South Pacific Ocean.  The ridge will produce northerly winds which will blow toward the top of the tropical cyclone.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be strong enough to prevent Tropical Cyclone Rita from getting stronger.  Rita could strengthen into the equivalent of a hurricane/typhoon during the next 24 hours.

The ridge over the South Pacific Ocean will steer Tropical Cyclone Rita toward the south during several days.  On its anticipated track the center to Rita could approach Vanuatu in 48 to 72 hours.

Tropical Cyclone Abela Forms over the South Indian Ocean in the Middle of Winter

Tropical Cyclone Abela formed over the South Indian Ocean in the middle of winter on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Cyclone Abela was located at latitude 12.9°S and longitude 62.4°E which put it about 640 miles (1030 km) northeast of Port Louis, Mauritius.  Abela was moving toward the west-southwest at 18 m.p.h. (29 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 989 mb.

Enough spiral banding developed in a low pressure system over the South Indian Ocean to allow the system to be classified as Tropical Cyclone Abela.  The circulation is not well organized.  Most of the thunderstorms were located in a thin primary rainband that wrapped around the western side of the center of circulation.  The other rainbands contained shallower clouds.  There was enough convection to produce some upper level divergence.  Winds to tropical storm force extend out about 150 miles (240 km) from the center of circulation.

The environment around Tropical Cyclone Abela is only marginal for further intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 26°C.  Northeasterly winds in the upper levels are creating a moderate amount of vertical wind shear.  The wind shear will limit the potential for intensification during the short term.  In about a day or so Abela will move over cooler SSTs and it should start to weaken.

A ridge of high pressure located east of Abela is steering the tropical cyclone toward the west-southwest and that general motion is expected to continue for another day or two.  On its anticipated track Tropical Cyclone Abela will pass north of Mauritius and La Reunion.  Abela is expected to reach the western end of the ridge and recurve toward the south as it nears the east coast of Madagascar.