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Hurricane Season 2011: Tropical Storm Keila (Northern Indian Ocean/Arabian Sea)
11.04.11
 
This radar image of Tropical Storm Keila's rainfall was captured by the TRMM satellite on Nov. 3, 2011 at 0254 UTC. › View larger image
This radar image of Tropical Storm Keila's rainfall was captured by the TRMM satellite on Nov. 3, 2011 at 0254 UTC (10:54 p.m. EDT, Nov. 2). Red areas indicate heavy rainfall spiraling into Keila's center. Light to moderate rainfall (green and blue) around much of the storm was falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour).
Credit: SSAI/NASA, Hal Pierce
MODIS captured Tropical Storm Keila Mon 07:10 UTC (3:10 a.m. EDT) on Nov. 1, 2011. › View larger image
This visible image of Tropical Storm Keila was captured by the MODIS instrument on NASA's Terra satellite on 07:10 UTC (3:10 a.m. EDT) on Nov. 1, 2011. At that time, Tropical Cyclone Keila was off the Arabian Peninsula and bringing rainfall to coastal Oman.
Credit: NASA Goddard MODIS Rapid Response Team
NASA's TRMM Satellite Views Oman's Tropical Depression Keila's Deadly Rains

Floodwaters created by Tropical Depression Keila's heavy rainfall were responsible for several deaths in Oman this week. NASA's TRMM satellite captured an image of that heavy rainfall as Tropical Depression Keila was over the Oman coast yesterday.

Tropical Storm Keila caused the deaths of at least 14 people when it came ashore in Oman on Thursday, November 3, 2011, according to Reuters News.

NASA's Tropical Rainfall Measuring Mission (TRMM) satellite flew overhead after Keila's landfall. TRMM's Microwave Imager (TMI) had a good early morning view Keila on November 3, 2011 at 0254 UTC (Nov. 2 at 10:54 p.m. ET).

The TMI rainfall analysis from these data was done at NASA's Goddard Space Flight Center in Greenbelt, Md. The data was overlaid on a sunlit visible and infrared image from TRMM's Visible and InfraRed Scanner (VIRS). The rainfall analysis showed a large band of moderate to heavy rainfall wrapping around the eastern side of the storm and drenching coastal Oman. Some of the rainfall within Tropical Depression Keila was falling at heavily at a rate of 2 inches/50 mm per hour. Heavy rainfall from Keila flooded major roadways, and a valley, according to Reuters News. Some cars were reported swept away.

The Joint Typhoon Warning Center noted on Nov. 4, that the center of Keila was located near 17.3 North and 55.3 East, about 80 nautical miles east-northeast of Salahlah, Oman. Keila's remnants continue to weaken and remain quasi-stationary while bringing more rains to the coastline. NASA's infrared satellite imagery from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite have shown warming cloud top temperatures. That means there's less strength in the atmosphere to uplift air and create the thunderstorms that power the tropical cyclone, and its weakening.

Keila's remnants are also battling moderate to strong wind shear (25 to 30 knots) which will help continue weakening the storm. Remants of Keila is forecast to hug the coast until Saturday, November 5, bringing more unwanted rainfall.

Text credit: Rob Gutro/Hal Pierce
NASA's Goddard Space Flight Center/SSAI, Greenbelt, Md.




November 3, 2011

Radar image of Tropical Storm Kelia's rainfall captured by the TRMM satellite on Nov. 2, 2011 at 1843 UTC › View larger image
This radar image of Tropical Storm Keila's rainfall was captured by the TRMM satellite on Nov. 2, 2011 at 1843 UTC. Red areas indicate heavy rainfall south of Keila's center, and over the Arabian Sea. Light to moderate rainfall (green and blue) was occurring around much of the storm, falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour).
Credit: SSAI/NASA, Hal Pierce
NASA's TRMM Satellite Sees Fading Rains in Tropical Depression Keila Over Oman

Tropical Storm Keila weakened to a tropical depression late yesterday, Nov. 2, and its center was over land in Oman. NASA's TRMM satellite saw the waning rainfall rates in the storm, as cloud top temperatures dropped.

A radar image of Tropical Storm Keila's rainfall was captured by NASA's Tropical Rainfall Measuring Mission (TRMM) satellite on Nov. 2, 2011 at 1843 UTC (2:43 p.m. EDT). The only area of heavy rainfall (2 inches/50 mm per hour) was south of Keila's center, and over the Arabian Sea. Light to moderate rainfall was occurring around much of the storm was falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour.

On November 2 at 2100 UTC (5 p.m. EDT) the Joint Typhoon Warning Center noted that Tropical Depression Keila is now over land and had weakened. Keila's maximum sustained winds are near 30 knots (35 mph). At that time Keila was about 55 nautical miles northeast of Salalah, Oman and moving to the north-northwest near 4 knots (5 mph).

Because Keila moved inland, and is now not expected to move southwest along the coast, it is expected to dissipate quickly. Infrared imagery from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite showed that cloud top temperatures are warming. Warming cloud tops mean the strength that creates the thunderstorms that make up the tropical cyclone is waning as there's not enough punch in the atmosphere to push the cloud tops higher (into colder air).

Although Keila is dealing with light wind shear the center is over land, and cut off from the warm powering waters of the Arabian Sea. Keila is expected to dissipate later today.

Text credit: Rob Gutro/Hal Pierce
NASA's Goddard Space Flight Center/SSAI, Greenbelt, Md.



November 2, 2011

This 3-D image from the TRMM satellite was captured on Nov. 2, 2011 at 0350 UTC (11:50 p.m. EDT, Nov. 1). › View larger image
This 3-D image from the TRMM satellite was captured on Nov. 2, 2011 at 0350 UTC (11:50 p.m. EDT, Nov. 1). Thunderstorms within Keila were reaching to heights of almost 17km (~10.6 miles).
Credit: SSAI/NASA, Hal Pierce
TRMM image of Tropical Storm Keila's rainfall on Nov. 2, 2011 at 0350 UTC (11:50 p.m. EDT, Nov. 1). › View larger image
This radar image of Tropical Storm Keila's rainfall was captured by the TRMM satellite on Nov. 2, 2011 at 0350 UTC (11:50 p.m. EDT, Nov. 1). Red areas indicate heavy rainfall spiraling into Keila's center. Light to moderate rainfall (green and blue) around much of the storm was falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour).
Credit: SSAI/NASA, Hal Pierce
TRMM Satellite Sees Tropical Storm Keila Form in the Arabian Sea

NASA's TRMM Satellite captured moderate rainfall and some high, towering clouds in the Arabian Sea's newborn Tropical Storm Keila.

The TRMM satellite passed directly above a recently formed tropical cyclone in the Arabian Sea on November 2, 2011 at 0350 UTC (11:50 p.m. EDT, Nov. 1). An analysis of rainfall was done using TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) instruments. TRMM data showed that rainfall rates with tropical storm Keila ranged from light to moderate along the south-eastern coast of Oman. Moderate to heavy rainfall was revealed to be spiraling into Keila's center of circulation in the Arabian Sea near the southeastern coast of Oman.

TRMM Precipitation Radar data was used to create a 3-D vertical structure of Tropical Storm Keila. It showed that a few towers near Keila's center were reaching heights of about 13 km (~8.1 miles). Powerful storms were shown in a large feeder band converging into Keila from the Arabian Sea.

At 1500 UTC (11 a.m. EDT) today, Nov. 2, Tropical Storm Keila had maximum sustained winds near 35 knots (40 mph). Keila's center was over the Yemen coast and about 630 nautical miles northeast of Aden, Yemen. It was near 17.0 North and 54.9 East. Although Keila was moving at 5 knots (6 mph) to the northeast, a building mid-level ridge (elongated area) of high pressure is building to the north of the storm, and will re-route it to the west-southwest.

Also this morning, infrared data from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite saw a burst of convection (developing thunderstorms) around the center of circulation and a band of thunderstorms to the south of the center.

Keila is expected to weaken a little as it continues to interact with the coastline, but slowly intensify tomorrow or Friday because of warm sea surface temperatures.

Keila made landfall early today (Nov. 2) in Oman, and is forecast to track to the west-southwest along the Oman and Yemen coastlines.

Text credit: Rob Gutro/Hal Pierce
NASA's Goddard Space Flight Center/SSAI, Greenbelt, Md.