TOKYO - Severe heat is forecast across much of Japan on July 16, with temperatures reaching 37 degrees Celsius in Nagoya and Kofu and sudden thunderstorms threatening the Kanto-Koshin and Tohoku regions through late at night.
Clouds are expected in parts of Kyushu, Tohoku and Hokkaido, while most other areas will see sunshine. Temperatures are forecast to rise sharply, particularly in eastern Japan, with many locations recording highs of at least 35 degrees.
A heatstroke alert has been issued for the largest number of regions so far this year. High humidity will add to the danger, while many areas are expected to remain above 25 degrees overnight, raising the risk of heatstroke even after sunset.
Forecast highs include 35 degrees in Tokyo, Osaka, Okayama, Hiroshima and Fukuoka, 36 degrees in Kochi, 34 degrees in Nagano and Kagoshima, 33 degrees in Aomori and Matsue, 32 degrees in Kanazawa, and 31 degrees in Sapporo, Sendai, Niigata and Naha. Kushiro is forecast to reach 22 degrees.
Atmospheric conditions will become increasingly unstable as temperatures rise in the afternoon, bringing scattered showers and thunderstorms to Kanto-Koshin and Tohoku. The probability of lightning is particularly high in inland Kanto, and residents are being urged to watch for lightning strikes and flooded roads caused by intense rain.
Rain clouds have already developed across northern and western Kanto, bringing sudden downpours to locations including Hachioji in western Tokyo and Ebina in Kanagawa Prefecture. Reports of particularly heavy rain have been concentrated in Tochigi, Gunma and western parts of the region.
Easterly and southeasterly winds are blowing across Kanto, causing air currents to converge over western and northern areas and encouraging the rapid development of rain clouds. Clouds have also begun forming over the Boso Peninsula in Chiba Prefecture, parts of Ibaraki Prefecture and central Kanagawa Prefecture.
Because the rain clouds are expected to move slowly, thunderstorms may develop directly over individual locations rather than approaching from elsewhere. The influence of a frontal zone in the upper atmosphere could prevent the clouds from weakening quickly after nightfall, leaving a risk of intense rain and lightning into the late evening, particularly in Gunma Prefecture and surrounding areas.
Conditions are expected to remain unstable on July 17 as southeasterly winds from waters off Kanto collide with winds from other directions, creating a shear line similar to a localized front.
Rain clouds extending north to south are forecast to approach from the sea while storms remaining over mountainous areas persist from the previous night. Rain is expected mainly in eastern Kanto during the morning, particularly in Chiba and Ibaraki prefectures, with temporary showers also possible in central Tokyo.
The area of rain is then forecast to shift westward during the afternoon, increasing the likelihood of showers and thunderstorms in mountainous and inland areas. Weather conditions could change suddenly anywhere in Kanto throughout the day, and residents are advised to carry umbrellas and check the latest forecasts before traveling.
Cloudy or rainy weather is expected mainly in northern Japan over the weekend. Although isolated showers may continue in Kanto, no prolonged or widespread rainfall is forecast, raising the possibility that the end of the rainy season could be announced as early as July 19 or July 20.
Source: ウェザーニュース
