KARACHI/ LAHORE: The Pakistan Meteorological Department said on Wednesday that a strong weather system in the eastern Arabian Sea might turn into a tropical cyclone by Thursday evening and cause heavy rain over coastal areas of Balochistan and Sindh, including Karachi, on Friday.

A cyclone advisory issued by Met Department's Director General Arif Mehmood said that a well-marked low pressure area in the eastern Arabian Sea on Tuesday had intensified into a depression (strong weather system) on Wednesday.

It said the current sea surface temperature was favourable for the development of this weather system into a tropical cyclone on Thursday evening, adding that the sea surface temperature and other meteorological parameters indicated that the tropical cyclone might intensify on Friday and Saturday. It will initially move in north-westerly direction.

“Based on probable track and estimated intensity of the expected cyclone, widespread thunderstorm rain with scattered heavy fall accompanied by strong gusty winds is expected along the Sindh-Makran coast on Friday evening,” the advisory said.

The department warned that the sea condition would become rough to very rough on Friday and advised fishermen who were in the open sea to return to the coast before Friday. “All fishermen of Sindh and Balochistan are advised not to venture in the open sea from Friday to Monday.”

S. Sarfaraz, Director of the Tropical Cyclone Warning Centre in Karachi, told Dawn that the distance and track of the expected cyclone, the speed with which it travelled and how far it was from Karachi could only be determined after the strong weather system, or depression, converted into a cyclone.

According to the classification of cyclonic disturbances for Pakistan, in case of a strong weather system, the speed of corresponding wind is 22-27 knots and the effect of depression during landfall is gusty winds which can damage detaching fruits from trees.

In June last year, cyclone Phet roared past Karachi before it made landfall over the coast of Thatta district. It left a trail of destruction in its wake, particularly along the Makran coast.

Meanwhile, most areas in the country, especially Sindh and southern Punjab, continued to suffer from an intense heat wave, although maximum temperatures dropped by one to two degrees centigrade.

The maximum temperature on Wednesday was 51 degrees centigrade in Jacobabad, Dadu and Larkana, 50 in Turbat, 49 in Sukkur and Rahimyar Khan, 48.3 in Bahawalpur, 48 in Dera Ghazi Khan, 45 in Multan and 43 in Peshawar.

Karachi's maximum temperature dropped by about four degrees centigrade to 35.2 from Tuesday's 39. The level of humidity, a measure of the amount of moisture in the air, increased to 67 per cent from Tuesday's 38 per cent.

The maximum temperature in Lahore dropped to 41 degrees centigrade from Tuesday's 43 because of strong winds. Humidity was 57 per cent in the morning and 31 per cent in the evening.