Tropical Cyclone Errol rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean northwest of Australia during Tuesday night.  At 5:00 a.m. EDT on Wednesday the center of Tropical Cyclone Errol was located at latitude 14.2°S and longitude 119.1°E which put the center about 325 miles (520 km) northwest of Broome, Australia. Errol was moving toward the west-southwest at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 940 mb.

A Watch is in effect for the coast of Western Australia from Kuri Bay to Broome.  The Watch includes Derby.

Tropical Cyclone Errol rapidly intensified to the equivalent of a  major hurricane during Tuesday night.  A very small circular eye with a diameter of 8 miles (13 km) was at the center of Errol’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Errol.  Storms near the core of Errol 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 Errol was small.  Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Errol’s circulation.  Winds to tropical storm force extended out 75 miles (120 km) from the center of Tropical Cyclone Errol.

The Hurricane Intensity Index (HII) for Tropical Cyclone Errol is 28.3.  The Hurricane Size index (HSI) is 7.2 and the Hurricane Wind Intensity Size Index (HWISI) is 35.5  Tropical Cyclone Errol is similar in size and intensity to Hurricane Charley when Charley hit Southwest Florida in 2004.

Tropical Cyclone Errol will move through an environment favorable for intensification during the next 24 hours.  Errol will move over water where where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge over Australia and the South Indian Ocean.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Tropical Cyclone Errol could continue to intensify during the next 24 hours unless an eyewall replacement cycle occurs.  If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could cause Errol to weaken.

Tropical Cyclone Errol will move around the northwestern part of a high pressure system over Australia.  The high pressure system will steer Errol toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Errol will remain north of Western Australia during the next day or so.  Errol could start to move back toward the southeast on Thursday.