Updated warnings from the MetO.
http://www.metoffice.gov.uk/public/weather/warnings#?date=2017-07-06
CFA:
"Two waves of thunderstorms are expected to affect the UK on Thursday. The first wave is expected to develop over southern England early on Thursday and push northwards across parts of the Midlands and East Anglia, clearing later in the morning or during the afternoon. The second wave is expected to develop further north, most likely over parts of northern England and the Midlands during the afternoon before moving eastwards and clearing during the evening or early hours of Friday. 20 to 30 mm of rain may fall within an hour and perhaps 50 to 80 mm in 2 or 3 hours, these totals most likely associated with the second wave of storms. However, such totals are likely to be very localised with many places staying dry."
Faxes for Thurs help explain the double threat scenario:
The risk in the south in the early morning onwards comes courtesy of the trough that tracks in from the south and moves NE to ENE during the day in that warm and humid air. The risk further north is associated with that slow moving cold front.
Ben,
Nr. Easingwold, North Yorkshire
30m asl