Wednesday, January 26, 2011

Two More Huge Storms Strike Australia: Anthony and Bianca Send More Pounding Rain To Flooded Nation

NASA's Aqua Satellite sees Tropical Depression Anthony heading toward Australia

NASA's Aqua Satellite captured a visible image of the former Tropical Storm Anthony, now weakened to a tropical depression, but forecasters aren't counting Anthony out yet. Despite its weakened condition Anthony continues to move west toward Queensland, Australia and into a more favorable area for sustaining a tropical cyclone.

NASA's Aqua Satellite captured this visible image on Jan. 26 at 03:23 UTC of a now weakened Tropical Depression Anthony as it continues to weaken in the South Pacific Ocean. Eastern Australia can be seen on the left side of this image.
Credit: NASA JPL, Ed Olsen

The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured a visible image on Jan. 26 at 03:23 UTC of Tropical Depression Anthony in the South Pacific Ocean. The image revealed a cloud-filled center of the storm.

At 0600 UTC (1 a.m. EST) on January 26, Anthony had progressed west and was now about 455 nautical miles west-northwest of Nomeau, New Caledonia. That places Anthony's center near 19.2 South and 159.1 East. Maximum sustained surface winds are estimated at 25 to 30 knots (28 mph/46 km/hr to 34 mph/55 km/hr) meaning that Anthony is still at tropical depression status.

The infrared imagery from the AIRS instrument showed a well-defined low level circulation center, although dry air is now wrapping into Anthony's northern quadrant. Dry air saps the moisture that creates the thunderstorms that power a tropical cyclone. Generally, the storm's convection (rapidly rising air that creates those thunderstorms) is weak throughout the storm, and only isolated strong areas of convection appear in the southeastern quadrant. That may change in the next day or two, however, as Anthony moves into an area more conducive to maintaining a tropical cyclone.

Vertical wind shear (winds that can weaken a tropical cyclone) has lessened and sea surface temperatures are warm enough to sustain and strengthen a tropical cyclone (between 28 and 30 Celsius/82 and 86 Fahrenheit). Computer forecast models have shown forecasters at the Joint Typhoon Warning Center that as the system tracks westward toward Australia, there is a fair chance that Anthony will regenerate or re-strengthen in the next 24-36 hours. Forecasters in Queensland, Australia will be watching Anthony very closely.

NASA's TRMM Satellite sees TD10S strengthen into Tropical Storm Bianca

The life of a cyclone is a complex one, and NASA satellites have kept track of a low that has now become Tropical Storm Bianca just off the northern coast of Western Australia.

What began as a low pressure system designated as System 98S on January 24, brought rains near Kuri Bay, Australia. On January 25, System 98S strengthened into the tenth tropical depression of the Southern Pacific Ocean hurricane season and was designated as "10S." Today, January 26, that low intensified into a tropical storm and was named Bianca.

NASA's TRMM satellite captured Tropical Storm Bianca's rainfall on Jan. 26. The yellow and green areas indicate moderate rainfall between .78 to 1.57 inches (20 to 340 mm) per hour. Over open waters, in the northwestern quadrant of the storm, there were some areas of heavy rainfall at almost 2 inches (50 mm) per hour.
Credit: NASA/SSAI, Hal Pierce

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite has been monitoring rainfall in the storm to assist area forecasters. NASA's TRMM satellite captured Tropical Storm Bianca's rainfall on January 26 at 01:09 UTC (Jan. 25 at 8:09 p.m. EST). Most of the rainfall around the storm was moderate, falling at rates between .78 to 1.57 inches (20 to 340 mm) per hour. Over open waters, in the northwestern quadrant of the storm, there were some areas of heavy rainfall at almost 2 inches (50 mm) per hour. The TRMM image also clearly showed the storm's center was located off the coast and over open waters. The TRMM satellite is managed by both NASA and JAXA, and images are created at NASA's Goddard Space Flight Center in Greenbelt, Md.

On January 26 at 02:20 UTC (Jan. 25 at 9:20 p.m. EST) NASA's Terra satellite passed over Bianca and the Moderate Resolution Spectroradiometer (MODIS) instrument captured an image of Bianca. The image showed a cloud-filled center of circulation just north of the northern coast of Western Australia. Most of the cloud cover associated with Bianca appeared over open waters at that time. The Terra satellite image can be found here. The image was created by NASA's MODIS Rapid Response Team, located at NASA Goddard.

At 1500 UTC (10 a.m. EST) on January 26, Tropical Storm Bianca had maximum sustained winds near 60 knots (69 mph/111 km/hr). It was centered about 225 nautical miles northeast of Learmonth, Australia near 19.8 South latitude and 116.2 East longitude. It was moving westward near 14 knots (16 mph/25 km/hr) and its center was staying off-shore.

Radar imagery from Port Hedland, Australia showed a well-defined low level circulation center with thunderstorms surrounding it. The Joint Typhoon Warning Center forecast indicates that the center of Bianca will stay over open waters as it continues to intensify over the next 24 hours. It is then expected to curve to the southeast and westerly winds are expected to increase and it will move into cooler waters, two factors that will help weaken the storm.

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NASA's Hurricane page: www.nasa.gov/hurricane

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