Tropical Storm IALY has intensified to a tropical cyclone stage and is now less than 300km from Mombasa, the Kenya Meteorological department has said.
A tropical cyclone is generally deemed to have formed once mean surface winds in excess of 35 knots (65 km/h) are observed.
In a marine update issued Tuesday evening, director David Gikungu said the new development marks a historic event in the South–West Indian Ocean and the intense system is forecast to cause adverse weather conditions at the coast.
“The center of IALY is currently 250km from Pemba Island and less than 300km from Mombasa. Peripheral bands of the system are beginning to affect parts of the East African coast,” he said.
The systems generally have a well-defined center which is surrounded by deep atmospheric convection and a closed wind circulation at the surface.
"Moderate rain, storms and windy conditions are forcast in the western periphery of the system along the coastal areas of Kenya and neighbouring countries," Gikungu added.
He said the tropical cyclone is positioned notably northwest 5°S/45°E, noting that tropical cyclones within 5°S/5°N are very rare.
The weatherman said strong southerly winds at 10-30 knots are expected over Kenya and Tanzania waters with waves of 1.5 to 3.6 meters expected along the Kenya coast resulting in moderate to rough sea conditions.
Gikungu said small boats and crafts are advised to avoid deep-sea areas throughtout the forecast period.
"IALY is expected to weaken starting Tuesday evening and into the night, ultimately dissipating by Wednesday, while remaining offshore despite passing within 150km of the Kenyan coast."
In the meantime, the weatherman said waves from the southeast are forcast to reach heights of 5-12 feet accompanied by large short period waves of 8-9 seconds in Kwale, Mombasa, Kilifi and Lamu counties from Wednesday through Thursday.
He said the sea will remain breezy in the afternoons characterised by rough waves during the forecast period due to moderately strong southerly winds of 10-23 knots.
"Wave heights from from the southeast are expected to decrease to 4-8ft with shorter periods of 9 seconds. Visibility is predicted to be moderate ranging from 9 to 10km in Kwale, Mombasa, Kilifi and Lamu," Gikungu said.
In its update earlier in the day, the Kenya Red Cross advised residents at the coastal strip to exercise caution after strong winds blew off roofs in the Majajani area of Kilifi county.
"Electric posts in Casuarina, Olimpia, Madunguni in Malindi and Garashi in Magarini, Kilifi County, fell down, while two posts in Jilore Trading Centre caught fire."
No casualties were reported, the humanitarian agency said.
