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Hurricane Season 2009: Tropical System 95S (Southern Pacific)
03.04.09
 
March 4, 2009

Tropical Cyclone 95S Made Landfall in Northwestern Australia

95S AIRS image> Click for larger image
Credit: NASA/JPL, Ed Olsen
Tropical Cyclone 95S is just a memory now, but on February 27, it caused some oilfields to stop production in northwestern Australia as it was making landfall in that region.

The Australian weather bureau reported that Cyclone 95S made landfall late on Saturday (Feb. 28) near the town of Port Hedland, Western Australia. It dumped up to 110 millimeters (4 inches) of rain. The last advisory from the Joint Typhoon Warning Center placed the center of the storm 15 miles southeast of Port Hedlund at 1100 Zulu Time (6 a.m. EST) on Feb. 28. That put the center of the storm near 18.4 south and 118.6 east.

The Bureau of Meteorology said the Low pressure area that was formerly 95S moved south and affected the Goldfields region on March 2.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured an infrared image of Cyclone 95S on Feb. 27 at 16:59 Zulu Time (1:59 p.m. EST).

The infrared image clearly shows a large temperature difference between 95S's high cold cloud tops (in purple) and the warm land temperatures in northwestern Australia (in yellow and orange which are around 80F).

The temperatures for the areas in purple (cloud tops) are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F.

The storm dissipated on Monday, March 2.

Text credit: Rob Gutro/NASA Goddard Space Flight Center


February 27, 2009

System 95S Will Likely Power up into a Tropical Cyclone This Weekend

AIRS image of System 95S Credit: NASA JPL, Ed Olsen
> Larger image
Forecasters at the Joint Typhoon Warning Center expect the area of low pressure off the northwestern coast of Australia to "power up" and become a tropical cyclone over the weekend of Feb.28-March 1.

On Feb. 27, the low, also designated as "System 95S" was located 545 miles east-northeast of Learmonth, Australia. That's near 17.5 degrees south latitude and 122.4 degrees east longitude. It was previously located over land, but is now moving over water. The winds were sustained between 25-30 knots (28-34 mph). The system is moving southwestward at 17 knots (19 mph). Minimum sea level pressure is estimated to be near 1002 millibars. The Joint Typhoon Warning Center noted that "sea surface temperatures will be very favorable for the low to continue developing as it tracks to the southwest.

The Australian government still has a tropical cyclone watch in force from Exmouth to Wallal. That's a large area that stretches from the New South Wales territory on the eastern side of the country to Western Australia territory, including the Northern Territory and the Queensland territory.

The Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite captured this visible image of System 95S on Feb. 27 at 06:05 UTC (1:05 a.m. EST). AIRS generates infrared, microwave and visible images, and in this image of cloud temperatures in infrared light, System 95S's swirling clouds are visible to the northwest of Australia.

The infrared image clearly shows a large temperature difference between System 95S's cloud tops and the warm ocean temperatures. The storm's lowest temperatures (in purple) are associated with high, cold cloud tops. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F.

AIRS infrared signal doesn't penetrate through clouds, so where there are clear skies AIRS reads the infrared (heat) signal from the ocean and land surfaces, revealing warmer temperatures (colored in orange and red). The orange temperatures are 80F (300 degrees Kelvin) or greater (the darker they are, the warmer they are). In this infrared image, the southwestern portion of Australia is a deep red color, indicating very warm land surfaces due to the heat wave that region has been experiencing. Tropical cyclones need sea surface temperatures of 80F to strengthen and maintain their strength.

The AIRS infrared data creates an accurate 3-D map of atmospheric temperature, water vapor and clouds, all of which are helpful to forecasters.

Text credit: Rob Gutro/NASA Goddard Space Flight Center


February 26, 2009

Northwestern Australia Posts Tropical Cyclone Watch Up in Anticipation

AIRS image of tropical system 95S> Click for larger image
Credit: NASA JPL, Ed Olsen
Forecasters in northwestern Australia are eyeing a low pressure area that has a chance for developing into a tropical cyclone. Already deemed "system 95S," the system is located 415 miles west-southwest of Darwin, Australia.

At 1800 Zulu Time (1 p.m. EST) on Feb. 26, 95S was located near 16.0 degrees south latitude and 124.7 degrees east longitude. Although the Joint Typhoon Warning Center, the organization that forecasts storms in this region of the world, gives it a fair chance of development, there is a tropical cyclone watch in effect from the towns of Exmouth to Wallal, Australia.

NASA's Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured this visible image of Cyclone 95S on Feb. 26 at 5:23 UTC (12:23 a.m. EST). 95S is the round area of clouds in the top left part of this satellite image.

Text credit: Rob Gutro/NASA Goddard Space Flight Center