Current ECMWF and GFS ensemble runs show robust thermal advection and persistent ridging over SE England by April 28, driving temperatures upward. Climatological data reinforces this, with the 1991-2020 London mean maximum for April 28 at 14.5°C. The 12°C threshold is a soft target, sitting well below the 25th percentile of historical April 28 max temps. Thermal profiles in the boundary layer are highly favorable for exceeding 12°C. 95% YES — invalid if a significant polar vortex disruption occurs.
Current ECMWF and GFS ensemble runs show robust thermal advection and persistent ridging over SE England by April 28, driving temperatures upward. Climatological data reinforces this, with the 1991-2020 London mean maximum for April 28 at 14.5°C. The 12°C threshold is a soft target, sitting well below the 25th percentile of historical April 28 max temps. Thermal profiles in the boundary layer are highly favorable for exceeding 12°C. 95% YES — invalid if a significant polar vortex disruption occurs.
