No. IV-18.4 - (IMD), Pune

31
12.3.6 The remaining sections of the report will deal with typical synoptic
situations causing strong and weak northeast monsoon conditions in the various
meteorological sub—divisions of the south Peninsula.
13. Severe cyclonic storm in the Bay of Bengal crossing Tamil Nadu
coast and causing strong to vigorous monsoon-
2 to 6 November 1966.
13.1 Storms and depressions form a very important category of synoptic
situations which cause active to vigorous northeast monsoon in the south Peninsula.
The heaviest falls occur when they cross coast and the extension of rainfall
to the north (discussed in paral2.1.4) is characteristic of these systems
during this season.
13.2 Storms and depressions coming close to or crossing the coast of the
Peninsula are mostly in October and November; their number decreases considerably
in December. In November and December, cyclonic storms are more numerous
than depressions. The entire Andhra Pradesh - Tamil Nadu coast is liable to be
affected by the storms and depressions in October; later in the season south
coastal Tamil Nadu is more vulnerable than the coastal line further north. The
coastal area near about Pondicherry-Cuddalore-Nagapattinam is the place where
the maximum number of storms and depressions cross coast in November and December.
In this section, we will discuss a typical cyclonic storm which crossed Tamil
Nadu coast and caused strong to vigorous monsoon conditions in the south
Peninsula.
13.3 A depression which formed over the south Andaman Sea on 1 November
1966, moved westwards, intensified into cyclonic storm and was over southeast
Bay with its centre near 9.5°N 88°E on the morning of 2 November (Fig. 13.1).
24 hour pressure change pattern became more organised/and the maximum negative
pressure changes were along Tamil Nadu coast and North
about —3 mbs).
Except for a feeble cyclonic circulation over Kerala in the very low levels,
the upper air flow pattern (Fig. 13.2) was mainly one of northeasterlies over