December 14, 2009
TRMM Sees 05B Winding Down off the Sri Lanka Coast
Hurricane Season 2009: Tropical Cyclone 5B (Northern Indian Ocean)
Tropical Depression 05B is dissipating on the east coast of Sri Lanka today and over the next couple of days, but not before bringing some moderate and heavy rain over the next couple of days to some areas in Sri Lanka and the southeast coast of India, from Chennai, southward.
The Joint Typhoon Warning Center issued its final advisory on Tropical Depression 05B, also known as Tropical Storm Ward, on Sunday, December 13 at 2100 UTC (4 p.m. ET). At that time, 05B's maximum sustained winds were near 34 mph. At that time, its center of circulation was located about 140 miles northeast of Colombo, Sri Lanka near 8.8 North latitude and 81.3 North longitude. It was crawling to the west-southwest near 4 mph.
The Tropical Rainfall Measuring Mission (TRMM) satellite is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA) designed to monitor and study tropical rainfall, and it captured 05B's rainfall on December 11.
The TRMM satellite monitors the global tropics as it circles the earth every 92.5 minutes at a height of 403 km (~250.4 miles). The TRMM satellite passed over 05B when it was newly formed in the Bay of Bengal on December 11, 2009 at 1610 UTC. TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) instruments were used in the rainfall analysis. That data is used to create visual images at NASA's Goddard Space Flight Center, located in Greenbelt, Md. The TRMM data showed a large area of rainfall near the center of the storm with some areas of intense rainfall greater than 50 mm/hr (~2 inches). The analysis was overlaid on an infrared image from TRMM's Visible and Infrared Scanner (VIRS). Tropical cyclone 05B was above tropical storm strength with winds over 35 knots (~40.3 mph) at that time.
The Precipitation Radar (PR) instrument has the unique capability of seeing through clouds to show tropical cyclones such as 05B in 3-D. An intense thunderstorm near the center of 05B was found by TRMM's PR to extend to heights above 13 km (~8 miles). Since that time, 05B has weakened into a tropical depression and its cloud heights have dropped.
Tropical cyclone 05B (Ward) that had been predicted to impact the southeastern coast of India, weakened to a tropical depression while moving over northeastern Sri Lanka. 05B was producing heavy rainfall over areas of the southwestern Bay Of Bengal and eastern Sri Lanka when the TRMM satellite passed over on December 14, 2009 at 0509 UTC. The rainfall analysis was derived from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) instruments and was overlaid on a combination infrared and visible image from TRMM's Visible and Infrared Scanner (VIRS).
Chennai and southeastern India will see scattered thunderstorms over the next several days as the system winds down. The areas in the southeast will experience scattered thunderstorms with light winds. Some downpours could be heavy at times. The current forecast calls for thunderstorms to diminish over southeastern India by Thursday, December 17.
In Sri Lanka, the Meteorology Department issued a cyclone warning on Sunday, December 13, and noted that the effects from the storm would peak by mid-day on Monday, December 14. Fishermen were cautioned against going out to sea because of rough seas and gusty winds. Scattered showers are expected today in the Northern, Eastern, Uva and North-Central Provinces of the country
Hal Pierce, NASA/SSAI and Rob Gutro, NASA/Goddard Space Flight Center
December 11, 2009
Tropical Cyclone 05B Forms Southeast of Chennai, India
Tropical Cyclone 05B has formed out of "System 96B" in the Northern Indian Ocean and is forecast to approach southeastern India by Sunday, December 13 and make landfall on Monday.
On Friday, December 11 at 15:00 UTC (10 a.m. ET or 8 p.m. local Asia/ Kolkata time in Chennai, India), Tropical Storm 05B had maximum sustained winds near 40 mph. It was located about 370 nautical miles southeast of Chennai, India, near 9.3 North latitude and 85.1 East longitude. It was moving north-northeast near 7mph, but is expected to gradually turn west and head for landfall.
Today, the Tropical Storm 05B is in an area of low wind shear, so it can continue to intensify. The only thing currently in 05B's path is a strong zonal jet stream over central India, but forecasters expect that to lift north in the next two days, and that means 05B can strengthen. Tropical Storm 05B is projected to turn west in the Bay of Bengal and make landfall in the state of Tamil Nadu by December 14.
The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured Tropical Storm 05B on Dec. 10 southeast of the Indian state of Tamil Nadu. Infrared imagery shows temperatures and the colder the cloud tops of thunderstorms in a tropical cyclone are the higher they are, and the stronger they are. The imagery from AIRS indicated some strong thunderstorms in Tropical Storm 05B.
Residents along the coast of southeastern India in the Tamil Nadu state should make preparations. Some cities that may be affected by heavy rains and gusty winds include: Chennai, Thanjavur, Mahabalipuram, Chengalpattu, Maraimalai Nagar, Mudichur, Madhurantakam and others in that region.
The Joint Typhoon Warning Center forecasts Tropical Storm 05B to make landfall south of Chennai before 12:00 UTC or 5 p.m. local Asia/Kolkata time on Monday, December 14.
Rob Gutro, NASA/Goddard Space Flight Center