The Met Office has published a yellow alert that covers the city and the rest of Hampshire.
It comes into force at 8pm and remains in place until 5am tomorrow.
Residents are being warned that there is potential of ‘some flooding’ and ‘disruption’ this evening.
Portsmouth, Gosport, Havant, Fareham, Waterlooville and Hayling Island are all covered by the weather warning.
On its website, the Met Office warns: ‘There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes or hail.
‘Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services.
‘Spray and sudden flooding could lead to difficult driving conditions and some road closures.
‘There is a slight chance that power cuts could occur and other services to some homes and businesses could be lost.’
The forecaster adds: ‘Whilst some places will remain dry, a few places may see 20-30 mm of rain fall in less than an hour, with frequent lightning and hail additional hazards.’