Whilst the thunderstorm may miss certain areas, it is likely storms will develop across London and the South East throughout Tuesday afternoon.
This will potentially bring torrential rain, gusty winds, frequent lightning and hail.
It is thought these thunderstorms could produce 30mm to 60mm of rain within the space of one to two hours.
There is a chance that travel and power supplies could be affected, so the Met Office has advised planning journeys ahead.
The yellow thunderstorm warning currently overlaps with the amber extreme heat warning across the South West.
The amber alert, which is valid for the western half of Hampshire, is forecast to remain in place until Thursday.
The yellow thunderstorms warning has been issued from 1pm today (Tuesday).