The meteorological bureau in Shanghai issued a red alarm, indicating extreme heat, early on Thursday afternoon, as the mercury climbed to 39 C by about 1 pm, a new high this summer.

For the first time this year, the meteorological authorities updated their orange heat alarm, released on Thursday morning, to red at 1:18 pm.

Under the influence of a subtropical anticyclone, the mercury is forecast to reach 39 C to 40 C on Thursday, the city’s meteorological bureau said.

Organizations and companies are urged to take emergency measures to protect employees from the heat, suspend outdoor work and take special care of the elderly, young and weak people.

Meteorologists said the highest temperature will still top 39 C on Friday and the current heat wave is not expected to break until next week.