Met Office Thunderstorm warnings are now in force for 4 consecutive days, from Monday to Thursday. This is concerning, because it means rainfall totals associated with this setup could become very high with such consecutive heavy rainfall. Some places could receive in excess of 75mm (3″), with potentially up to 100mm (4″) in some isolated areas.
The first risk of thunderstorms is valid this evening with a trough set to develop across the Irish Sea and across western fringes of England and Wales. This may produce some isolated downpours with high rainfall totals, hail and gusty winds a possibility.
Some minor activity is also possible across the South East of England overnight with scattered storms producing some lightning.
The following thunderstorm risk map (produced by us) is valid from Sunday night (tonight) until early Tuesday. It highlights the likely breakout in the west whilst emphasizing that scattered storms may break out elsewhere to.
Through Monday, there is a continued risk of thunderstorm development across England and Wales. This, especially, for western parts of England (the West Midlands, NW England), and much of Wales. Thunderstorm activity could become very strong in these areas later on Monday and into the early hours of Tuesday with supercellular activity possible. These storms may advance into Scotland through Tuesday, with the potential for Channel storms to affect southern coasts on Tuesday.
The detail for Wednesday and Thursday is very futile at the moment, however, there remains a good likelihood of severe storm activity. The very unstable plume is likely to continue, and with a more pronounced break in the pressure, a widespread thunderstorm outbreak is entirely possible from Wednesday and into Thursday.