At 0600 UTC (1 a.m. EST) on December 15, System 91S was located about 310 miles northwest of Learmonth, Australia near 18.1 South latitude and 110.6 East longitude. Learmonth is located in the extreme western coast of Australia.
When NASA’s Aqua satellite passed over System 91S on Dec. 15 at 06:05 UTC (1:05 a.m. EST) the Atmospheric Infrared Sounder (AIRS) Instrument captured an infrared image that showed a large area of strong convection around the center of the system’s circulation. The cloud tops were as cold as or colder than -63 Fahrenheit, indicating high, strong thunderstorms. The circulation of the low was clearly evident in the visible image from the AIRS instrument.
The strongest surface winds appear to be on the northeastern side of the storm between 25-30 knots (28-34 mph or 46-55 km/hr) where the strong convection is occurring. Minimum estimated pressure is 1000 millibars. System 91S is moving southwest near 5 mph.