Malcolm part 1:
A quick look at a couple of the EPS short range 500mb NH anomaly charts from last night which illustrate quite well ( imo) the amplification of the North American ridge, resulting in a split vortex lobe, with the more relevant upper trough ( from the UK viewpoint) over Newfoundland. This is then due to track east towards Iceland with a very strong westerly upper jet running across the Atlantic south of it but that is outside the remit of this thread. The GEFS pretty much in agreement with this.
Meanwhile a familiar pattern unfolds over the UK over the next few days. Dawn breaks after a fresh clear night in many areas apart from eastern coastal regions where low cloud remains the problem and further south along the south coast where more humid air accompanied by showery outbreaks has encroached during the night. It may even give the odd storm. The showers and humid air will track north as far as the southern Midlands during the day thus intermittent sunshine albeit another warm day. Clearer skies further north but the usual caveat vis the NE/E coast. The humidity charts, the 0300 geostationary WV, and the Camborne 00 sounding illustrate the above.
The cloudy humid air will continue to move north overnight and through Friday thus spreading the shower area but these will tend to fizzle out during the day although as temps rise a few more could be triggered in the south. So generally another warm day, sunnier away the above area, but with the usual proviso of course.