KUALA LUMPUR, July 21 — Thunderstorms, heavy rain and strong winds are expected to hit several areas across the country, including parts of Perlis, Kedah, Perak, Selangor, Johor and Sarawak, according to the Malaysian Meteorological Department (MetMalaysia).

In an advisory issued at 3.45pm today, MetMalaysia said the weather conditions were expected to persist until 6pm in affected areas.

The warning covers Kedah, including Langkawi, Kubang Pasu, Padang Terap, Sik, Baling, Kulim and Bandar Baharu, as well as Perak and several districts in Kelantan, Terengganu and Pahang.

In Selangor, affected areas include Sabak Bernam, Kuala Selangor, Hulu Selangor, Klang, Gombak, Petaling and Hulu Langat, while Kuala Lumpur has also been placed under the thunderstorm warning.

Other affected areas include Jelebu in Negeri Sembilan, parts of Johor including Mersing, Pontian, Kulai, Kota Tinggi and Johor Bahru, as well as several divisions in Sarawak and Sabah.

MetMalaysia said the warning was issued when there were signs of thunderstorms with rainfall intensity exceeding 20mm per hour that were either imminent or expected to occur for more than an hour.

The department added that thunderstorm warnings are short-term alerts valid for no longer than six hours for each issuance.