29 Jun 2023 | 04:00 PM UTC
Japan: Adverse weather forecast across much of the country through at least July 1 /update 1
Severe weather forecast across much of Japan through at least July 1. Possible transport, business, and utility disruptions.
Event
Severe weather is forecast across much of Japan through at least July 1. The Japan Meteorological Agency (JMA) has warned a low-pressure and associated weather front will bring unstable conditions over a wide area from Kyushu to northern and western Japan. Thunderstorms may bring heavy downpours, strong wind gusts, lightning, and hail across the affected areas. Rainfall totals of up to 20 cm (8 inches) are expected in parts of northern Kyushu region, 18 cm (7 inches) in parts of the Hokuriku and Kinki regions, 15 cm (6 inches) in southern Kyushu and Tokai regions, 12 cm (5 inches) in Chugoku and Kanto-Koshin regions, and 10 cm (4 inches) in Tohoku region late June 29-30. Further rainfall amounts of 10-20 cm (4-8 inches) are expected in parts of northern and southern Kyushu and Kinki regions from late June 30-July 1, as well as 10 -15 cm (4-6 inches) in parts of Chugoku, Hokuriku, Tokai, and Kanto-Koshin regions.
As of June 29, the JMA has issued the following weather warnings across the country:
Red heavy rain and landslide warnings (the middle level on a three-tier scale): Parts of Fukui Prefecture in Hokuriku Region and Saga Prefecture in northern Kyushu Region.
Yellow heavy rain and inundation warnings: Isihikari, Kamikawa, and Sorachi regions in Hokkaido Prefecture and parts of Shimane Prefecture in Chugoku Region.
Yellow heavy rain and landslide warnings: Parts of Gifu Prefecture in Tokai Region, Ishikawa and Toyama Prefectures in Tohoku Region, Shiga Prefecture in Kinki Region, Shimane and Tottori Prefectures in Chugoku Region, and Fukuoka, Kumamoto, Oita, and Saga prefectures in northern Kyushu Region.
Yellow flood warnings: Isihikari, Kamikawa, and Sorachi regions in Hokkaido Prefecture.
Yellow thunderstorm warnings: Across Tokai, Hokuriku, Kinki, Shikoku, and northern and southern Kyushu regions, as well as Isihikari, Kamikawa, Rumoi, and Shirbeshi, and Sorachi regions in Hokkaido Prefecture, Saitama and Tochigi prefectures in Kanto Koshin Region, and Yonagunijima region in Okinawa Prefecture.
Yellow storm gale warnings: Much of northern Kyushu Region and parts of Kanagawa Prefecture in the Kanto Koshin Region, Ishikawa Prefecture in the Hokuriku Region, Wakayama Prefecture in the Kinki Region, and Shimane Prefecture in Chugoku Region.
Yellow high wave warnings: Parts of Kanagawa Prefecture in the Kanto Koshin Region, Shimane Prefecture in the Chugoku Region, Fukuoka, Kumamoto, Nagasaki, and Yamaguchi prefectures in northern Kyushu Region, and Kagoshima Prefecture in southern Kyushu Region.
Yellow storm surge warnings: Parts of Fukui and Toyama prefectures in Hokuriku Region and Hyogo and Kyoto prefectures in Kinki Region.
Yellow dense fog warnings: Across Hokkaido Prefecture and parts of Aomori Prefecture in the Tohoku Region and Chiba, Gunma, Ibaraki, and Tokyo prefectures in the Kanto Koshin Region.
Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.
As of June 29, authorities have issued evacuation orders for a small number of households in parts of Aichi, Hyogo, Nagasaki, and Nara prefectures due to the threat of heavy rainfall and landslides.
Hazardous Conditions
Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall.
Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.
Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.
Severe weather could also trigger flight delays and cancellations at airports in the affected areas. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.
Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.
Advice
Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Charge battery-powered devices in the case of prolonged electricity outages.
