eastern region oil spill disaster contingency plan - Indian Coast Guard

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CHAPTER III
Annex-8
SYNOPTIC AND CLIMATOLOGICAL FEATURES IN EASTERN REGION
January
1. General. The month of January and February constitute the winter
season. However, of the northern India, December is also considered as winter
month. The weather is usually fine over most ports of the Bat of Bengal with
steady NEly winds. Equally weather accompanied by thunder activity may occur
off East Coast particularly along with Andhra to North Tamil Nadu coast becomes
insignificant in this month, During this season rainfall mainly occurs over the
Northern and Central parts of the Country and is mainly associated with the
passage of Western Disturbances and induced laws.
2. Surface Pressure Pattern. The pressure gradient continues to be
weak over the entire country as in the month of December, with the features
high pressure cell in the northern parts and low pressures over southern parts of
India. A ridgeline running along the East Coast of Peninsula and two well-marked
trough one extending from Gujarat to Kerala and another along the Tenassarim
coast are the seasonal features.
3. Surface Wind & Visibility. The winds blow chiefly from NEly all over the
Bay of Bengal with speeds of the order of 5-10 kts over north Bay and 10-15
kms. Over Central Bay, South Bay and Andaman sea. Visibility is generally good
except for fog and haze off West Bengal and Orissa coast due to passage of
Western Disturbance over the sea.
4. Cyclonic Storms and Depression : Cyclonic. storms and Depression
normally do not form in the Arabian sea during this season. In the Bay of
Bengal, they are very few. They usually originate between latitude 5 deg to 9
deg North and west of longitude 92 deg East during the winter season. The
frequency of formation of Cyclone and Depression per year is 0.14 and 0.16
respectively. They move in Westerly/Northwesterly direction and strike the North
Tamil Nadu coast or East coast of Sri Lanka. They bend to weaken at times over
the sea areas during the course of their movement. Heavy rainfall occurs over
North Eastern sector of the track of system.
5. Western Disturbances. The normal fine to fair weather of the
Northern India and Northern parts of Bay and Arabian Sea occasionally changes