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Hurricane Season 2011: Tropical Depression 04A (Northern Indian Ocean/Arabian Sea)
11.10.11
 
Tropical Depression 04A's rainfall was captured by the TRMM satellite on Nov. 9, 2011 at 10:30 a.m. EDT. › View larger image
This radar image of Tropical Depression 04A's rainfall was captured by the TRMM satellite on Nov. 9, 2011 at 10:30 a.m. EDT. The red areas near the center and northeast of 04A's center indicate heavy rainfall of 2 inches (50 mm) per hour. 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
NASA Sees Some Heavy Rain in Oman's Dissipating Tropical Depression

The remnants of Tropical Depression 04A is still off the coast of Oman and continues to weaken, but NASA satellite data showed some areas of very heavy rainfall over the Arabian Sea.

The Joint Typhoon Warning Center (JTWC) may have issued its last warning on dissipating tropical depression 04W on November 9, but the remnants of the tropical depression are still lingering off the coast of Oman today. When the Tropical Rainfall Measuring Mission satellite called "TRMM" passed over 04A on Nov. 9 at 15:30 UTC (10:30 a.m. EDT) the instruments aboard gathered data that provided a rainfall analysis. The TRMM satellite is co-managed by NASA and JAXA, and the data was created into an image at NASA's Goddard Space Flight Center in Greenbelt, Md.

The data from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) showed heavy rainfall extended from 04A's location in the Arabian Sea north-eastward toward Pakistan. Some of the heaviest rainfall was occurring over the Arabian Sea and was falling at a rate of over 2 inches (50 mm) per hour.

On November 10, the Times of Oman reported that because of 04A's proximity to the Oman coast, the Al Wusta, Al Sharqiya and Dhofar regions can expect some of those heavy rains seen by NASA's TRMM satellite yesterday. Rainfall is expected to continue today over the Muscat Governate as well as the Al Hajr Mountains, so flooding and landslides may be possible. Many areas have already reported light and moderate rainfall from the remnants of Tropical Depression 04A as it continues to weaken off-shore.

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



November 9, 2011

NASA'S TRMM satellite flew over Tropical Depression 4A (TD4A) on Nov. 9 at 1529 UTC (10:29 EST) › View larger image
NASA'S TRMM satellite flew over Tropical Depression 4A (TD4A) on Nov. 9 at 1529 UTC (10:29 EST), and the Precipitation Radar instrument onboard measured rainfall rates between 1 and 1.2 inches (2.5 to 3 centimeters) per hour (orange) falling just off-shore from Oman.
Credit: NRL/NASA/TRMM
Tropical Depression 4A Near Oman

Oman can't seem to get a break from tropical cyclones this month. Tropical Storm Keila dropped heavy rainfall just last week and now another tropical depression has formed off the Oman coast. NASA's TRMM satellite identified heavy rainfall occurring in Tropical Depression 4A just off the Oman coast.

When the Tropical Rainfall Measuring Mission (TRMM) satellite flew over Tropical Depression 4A (TD4A) on Nov. 9 at 1529 UTC (10:29 EST), the Precipitation Radar instrument onboard measured rainfall rates between 1 and 1.2 inches (2.5 to 3 centimeters) per hour falling just off-shore from Oman. At that time, maximum sustained winds were near 30 knots (35 mph) and it was centered near 15.7 North and 58.5 East, about 465 nautical miles south of Mucat, Oman. TD4 had a minimum central pressure of 1000 millibars and was moving to the north-northwest near 2 knots (3 mph).

Satellite data shows that the low-level center of circulation is fully-exposed to outside winds, and the strongest convection (rising air that forms the thunderstorms that make up the tropical depression) a limited and mostly to the north of the center. That's an indication of strong wind shear from the south. The Joint Typhoon Warning Center forecast calls for TD4A to slowly move to the north-northwest and dissipate over the water.

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




November 7, 2011

Another Possible Tropical Cyclone Approaches Oman

On November 2011, TRMM passed over another stormy area heading toward Oman from the Arabian sea.
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On November 2011 at 1541 UTC the TRMM satellite passed over another stormy area heading toward Oman from the Arabian sea. Another tropical cyclone may be forming in this area less than a week after deadly tropical storm Keila hit Oman. A rainfall analysis from TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) is shown in the image on the upper left. Rainfall derived from PR data, shown in a lighter shade, reveals that an area of extremely heavy rainfall was located in the center of this stormy area.


TRMM's PR data show the 3-D structure of this stormy area.
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TRMM's PR data were again used to show the 3-D structure of this stormy area. Some of these very powerful storms were towering to heights of about 17km (~10.6 miles). Radar Reflectivity values of over 55 dBZ within these storms is additional evidence of very heavy rainfall.

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