eastern region oil spill disaster contingency plan - Indian Coast Guard

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of low pressure running from Bihar plateau to extreme South peninsula is a
general feature of the month. A similar trough is also seen from Bihar plateau to
Northeast India as the season progresses. Two high pressures cells one each
over Bay of Bengal and Arabian sea are typical features. The pressure gradient
over the country continues to bed slack except near the coastal area where by
the end of the month, strong pressure gradient prevails. In general the pressure
field over the entire country is diffused and the difference in pressure from
extreme north and south of the subcontinent is of the order of 2 to 3 millibars. A
single isobar is generally seen running parallel to the coastal line of the country
in the month of April.
22. Winds. A common observation during this month is the wind
discontinuity line along longitude 78-degree East. The surface winds along the
East Coast are generally light and blow from SEly / SWly direction. Land and sea
breezes are very prominent in this month due to the strong pressure gradient
along the coast. The surface winds over the open waters follow clockwise
circulation with its central region near East central and adjoining South East Bay.
23. Sea State. Average sea state is 2-3 over North Bay, Central Bay and
Northern parts of South Bay and greater than and equal to 3 over Southern parts
of South Bay greater than and equal to 3 over Southern parts of South Bay. Sea
State may worsen in case of a Depression /Storm.
24. Visibility: Visibility is generally good except when restricted by falling
rains of a thunderstorm activity over the Head Bay region and formation of
Depression / Cyclonic Storms over Bay.
25. Thunder Storm Activity. This is the main weather phenomenon of
the Pre-monsoon period. It is confined to the land / coastal areas. An increase in
the frequency, intensity and special distribution of the Thunder Storm activity is
generally observed as the season progresses. Preferred areas of this activity are
Madhya Pradesh in Central India, Orissa, Bihar, Gangetic West Bengal and
adjoining states of NE India.
26. Norwesters. The frequency of Norwesters over Gangetic West
Bengal and adjoining states also increases and these are accompanied by
stronger thunder squalls during the month. On rare occasions they attain the
intensity of Tornado.
27. Squalls. Thunderstorms during pre-monsoon period are mostly
accompanied by squalls. In the central parts of the country and over peninsula