Japan: High temperatures are forecast to persist across much of the country through at least July 16 /update 1

Forecast models indicate that high temperatures will persist across much of Japan through at least July 16. As of July 4, the Japan Meteorological Agency (JMA) has issued a weather bulletin advising that high temperatures are expected across western regions through July 8 and in Okinawa and the Amami Islands through July 11. High temperatures have also been recorded across many other parts of the country in recent days, with highs of up to 39 C (102 F) in Shizuoka Prefecture July 4. Temperatures of around 35-37 C (95-99 F) are forecast in central regions July 5 and heatstroke alerts have been issued for parts of Okinawa Prefecture, Kagoshima Prefecture, Nagasaki Prefecture, Kochi Prefecture, Tokushima Prefecture, Wakayama Prefecture, Kyoto Prefecture, Mie Prefecture, Aichi Prefecture, Shizuoka Prefecture, and Chiba Prefecture. Longer-term forecasts indicate temperatures well above average are expected in northern regions and the Okinawa islands and slightly above average across the rest of the country July 12-16.

The extended period of oppressive heat and dry conditions may produce ideal circumstances for wildfire growth throughout the region. Heatwaves also threaten vulnerable groups - such as the elderly, children, pregnant women, and those with respiratory illnesses - due to the increased possibility of heat stroke or heat exhaustion during prolonged exposure to high temperatures. These health risks could also affect relatively healthy individuals during significant heatwave events.

Very high temperatures could warp rail tracks and force passenger and freight trains to operate at reduced speeds. Damage to road surfaces is also possible, and overheated vehicles could worsen traffic problems in urban areas where congestion is already a problem. Commercial trucking disruptions might occur, as very high temperatures put more stress on vehicles and make tire blowouts more common. Major flight disruptions are unlikely at regional airports; however, general aviation disruptions are possible, and some air freight carriers could reduce cargo loads. High temperatures could lead to an increased demand for electricity, which might trigger localized brownouts or blackouts, exacerbating hazardous conditions when air conditioning is no longer possible.