Sunday, October 28, 2007

The well marked low in the Arabian Sea could now develop into a depression, after a day of stagnation. The JTWC announces the chances of it forming into a cyclone in the the next 24 hrs. as "good".

Meanwhile, on the eastern side, carrying on from yesterday's blog, the low is now centered east/south-east of Chennai, as on night of 27th. The rains have commenced along the south Tamil Nadu coast. The system may not gather too much strenght now, and may not go beyond a dperession level, as the low lies just south of an upper level ridge axis, and the minimum sea level pressure isestimated to be near 1005 mb. But the interiors of Tamil Nadu and Karnatak a will get rains from 29th. onwards.

The "power house" of the North-East monsoon is actually over North China/Siberia. This region is normally dominated by a large anti cyclone, or high pressure area. Similarity of this with the summer monsoon is that the "power house" of the summer monsoon is the Mascerenes High off Madagascar.
From these "power houses, the summer monsoon winds blow, and change direction on crossing the equator, and the North-East monsoon is fed by the strong winds blowing from the Siberia High, across the Bay.
During the North-East Monsoon, occasional strong flows of cold air from the Siberian High is associated with the development of low pressure systems over the regions of Sarawak and East Malaysia. Remnants of these low pressure systems that affect Malasia, cross into the bay, and move westwards to Tamil Nadu.
Also, the sub tropical westerly jet stream is a characteristic feature of the NE Monsoon.

Hence, as mentioned, we can expect some more low's to follow till the middle of November from the Bay.



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