A few showers may be possible on Sunday morning from mid-level cloud, drifting eastwards. Then, provided sufficient insolation occurs, falling heights as upper trough approaches combined with a couple of zones of low-level wind convergence should provide the lift required to generate a few isolated heavy showers or thunderstorms. Modelled CAPE of 500-1,000 Jkg^-1 seems reasonable given dewpoints of 12-15C - once again ignoring the GFS with its 17-18C dewpoints and hence unrealistic CAPE and shower coverage. Late arrival of upper forcing suggests that the main timeframe of interest will be 17-18z onwards, the main focus being Lincolnshire and/or East Anglia.

The exact location of one or two convergence zones will be key to the areas affected, and there is some spread amongst NWP output at present as to whether Lincolnshire or East Anglia will be most favourable, or perhaps a combination of both as the upper trough continues to allow showers to develop overnight with eastward migration. Hence the (low-end) SLGT may need tweaking in shape as confidence improves. There could be a weak funnel / tornado as dewpoint depressions reduce during the evening hours, and cloud bases lower somewhat.

Late in the night, there is a low risk of some remnant elevated convection drifting close to SE England from France, but this appears to be a decreasing trend in recent model runs and probably not worth a mention.