Thunderstorms and heavy rainfall are forecasted to occur starting from 23 May 2026, 22:30 WIB in parts of Sumatera Utara especially in: Aek Natas, Ajibata, Bahorok, Bandar Pasir Mandoge, Barusjahe, Besitang, Binjai, Binjai Utara, Bonatua Lunasi, Dolok Panribuan, Dolok Pardamean, Dolok Silau, Gunung Meriah, Habinsaran, Halongonan, Hamparan Perak, Jorlang Hataran, Kuala, Kutalimbaru, Kutambaru, Lumban Julu, Lumut, Medan Johor, Medan Selayang, Na Ix - X, Nainggolan, Nassau, Onan Runggu, Padang Tualang, Palipi, Panei, Parmaksian, Pematang Sidamanik, Porsea, Purba, Salapian, Sawit Seberang, Sei Bingei, Sei Lepan, Selesai, Siantar Narumonda, Sibabangun, Sibolangit, Sidamanik, Silaen, Silou Kahean, Simangambat, Simanindo, Sirapit, Stabat, Uluan, Wampu. These conditions may lead to reduced visibility, strong winds, and localized flooding. The public is strongly advised to remain vigilant during this period, limit outdoor activities, and take all necessary precautions to ensure safety. Conditions are expected to gradually improve by 24 May 2026, 02:30 WIB.