When a relatively stable anticyclone forms on the east side of Shanghai, the possible weather in Shanghai is

The influence of subtropical high edge may include: thunderstorm (summer)

North of subtropical ridge: sunny, hot and humid.

South of subtropical high ridge: convective weather.

So it should be: sunny or strong convective weather. (depending on the season)

You can refer to the entrance examination paper of Chinese Academy of Sciences, which contains (subtropical high and weather in China).