As the low pressure clear itself into Norway, a gentle southwesterly breeze will introduce slightly warmer condition across parts of England and Wales. Scattered showers and isolated thunderstorms will develop across parts of NW Wales, S Wales, Bristol and Devon in the early morning, bringing a risk of localised flooding
Cloud should gradually clear to the north and/or break up through the day with increasing insolation leading to heating of a moist low-level airmass (T 15-17C / Td 10-13C), especially from late morning onwards. This, in conjunction with a mid-level cold pool drifting northeastwards, will yield 500-1,000 J/kg MLCAPE across portions of England and east Wales. Numerous heavy showers and thunderstorms are likely to develop, particularly aided by areas of low-level convergence such as from southwest England across the south Midlands to East Anglia. Forecast soundings suggest ELTs around -45C, with cloud tops potentially around 28,000ft.
For the most part, limited mid/upper flow will result in weak wind shear, with pulse-type mode most favoured. That said, some backing of the low-level winds over East Anglia and eastern Lincolnshire could bolster 0-6km DLS to >30kts, perhaps aiding somewhat with storm longevity in these areas. Cells will mature as they drift gradually northeastwards, therefore the greatest lightning risk will tend to be favoured more towards eastern England, not least because some areas may have several thunderstorms pass in the vicinity through the afternoon. It is worth noting that the mid-level cold pool will begin to move out to the North Sea from 12z, and so gradual warming aloft from the southwest through the afternoon may result in shower/thunderstorm activity reducing across southwestern areas a little earlier than the typical diurnal cycle would dictate. The strongest cells may produce wind gusts up to 40mph and hail perhaps a little over 1cm in diameter, but the lack of any substantial shear will preclude the risk of any severe convective weather (aside from any localised flooding).
You can download the kml file of the convective outlook here:
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