Jul 10 2012 By Jenny Gray. Video by Carl Gavaghan
There are no Met and Piccadilly line trains running after a lightening strike knocked out a signal at Hillingdon station.
A Transport for London spokesman said engineers are working to fix the problem.
A Met Office spokesman said the Uxbridge area was being subjected to localised heavy showers and some lightning.
He said the storm will pass but showers could continue into the evening.
The forecast is similar for tomorrow and more heavy rainfall is expected on Friday.
By 4.30pm this afternoon, 3 mm of rain had fallen at Heathrow but this is expected to rise dramatically as rain continues.
Like everywhere else in the country, June was the wettest on record for the area and July has started off the same way.
Watch video below