The most recent (init. 06Z Thursday) GFS run has temperatures of 2°C
with heavy rain for 12 and 18Z Saturday in the west Midlands. Even
the London area is only given 8°C. This will be record-breaking
stuff if it comes off. That reason alone is enough to make one doubt
it. The forecast 850 mb temp is about -1°C but even so....

Tudor Hughes, Warlingham, Surrey.