Cyclone Nilofar Targets India's Gujarat State, Southern Pakistan (FORECAST)

By Jon Erdman
Published: October 27,2014



 
Cyclone Nilofar is steadily gaining strength in the Arabian Sea about 750 miles south-southwest of Karachi, Pakistan.
(MORE: Expert Analysis | Hurricane Central)
As of early Tuesday morning local time (9.5 hours ahead of U.S. Eastern time), Nilofar had strengthened to the equivalent of a Category 2 hurricane, with winds estimated at 105 mph, according to the U.S. Joint Typhoon Warning Center.
(MORE: Tropical Terms You Need to Know)
Incidentally, the term "hurricane" is not used in this case. In the southwestern Pacific and Indian Basins, tropical cyclones are simply called "cyclones."
(MORE: Hurricane vs Typhoon vs Cyclone - What's the Difference?)
Nilofar is expected to begin a track toward the north or north-northwest through late Tuesday under the steering influence of an upper-level high pressure system centered over southern India. During this time, Nilofar will be experiencing minimal wind shear and is, therefore, expected to intensify to a Category 3 equivalent tropical cyclone.
By mid-week, Nilofar will then curl sharply and accelerate toward the east-northeast, as upper-level jet stream winds grab hold of the cyclone. On this track, Nilofar is likely to pass well to the east of the Arabian Peninsula.
These jet stream winds will impart increasing vertical wind shear, and drier air may also work into the cyclone. Both of these factors are expected to weaken Nilofar by the time it makes landfall somewhere along the coast of India's Gujarat state or extreme southeast Pakistan Thursday.
The India Meteorological Department (IMD) -- the agency responsible for tropical cyclone advisories in the northern Indian Ocean, including the Arabian Sea -- has issued a yellow message cyclone alert for the northern coast of India's Gujarat state.
The IMD warned of "extensive damage to thatched roofs and huts" near the landfall location of Nilofar Thursday and urged fishermen along and off the Gujarat coast to return to port. Coastal hut dwellers were urged to move to safer location.
The Pakistan Meteorological Department warned of isolated heavy rainfall and strong gusty winds in the Lower Sindh including Karachi, and coastal areas of Balochistan from Wednesday night into Friday.
Karachi, one of the world's most populous megacities (2014 population estimate: 23.5 million), only averages about 7.9 inches of rain each year. Depending on the track of Nilofar, over one inch of total rainfall is possible, which could trigger flash flooding.
(FORECAST: Karachi | Mumbai)

How Unusual Is This?

The image below of global tropical cyclone tracks indicates that Arabian Sea tropical cyclones are not as unusual as they sound.
(MORE: Strangest Locations Hurricanes Have Formed Around the World)
Each year, an average of 1-2 tropical cyclones form in the Arabian Sea, according to a 2011 climatology study by Amato Evan and Suzana Camargo.
These cyclones are most likely to form in two periods: from May - June and October - November. The mid-late summer period is typically not favorable, thanks to increased wind shear from the wet phase of the Asian monsoon.
(MORE: Where the Hurricane Season Peaks Twice)
In June 2007, Cyclone Gonu was the most intense Arabian Sea storm on record, making landfall in Oman, then in southern Iran.
Gonu claimed 100 lives in Oman, Iran and the United Arab Emirates and was responsible for $4 billion in damage, according to the Evan and Camargo study.
Almost exactly three years later, Cyclone Phet alarmingly intensified to a Category 4 equivalent cyclone, before weakening to a Category 1 storm upon making landfall on the eastern tip of Oman, east of the capital city of Muscat.
In May 1999, Cyclone ARB 01 slammed into Pakistan near Karachi as a strong Category 3 equivalent storm, killing at least 700 in Pakistan. This was the strongest tropical cyclone on record to hit Pakistan.
(MORE: Deadliest Tropical Cyclones in World History)
In the limited historical record, however, strong cyclones in the Arabian Sea are more rare than other basins, due to the proximity of dry air from the Arabian Desert, the aforementioned increased wind shear during the wet phase of the Asian monsoon, and the basin's overall small size.