ECMWF operational runs consistently project a robust high-pressure ridge establishing over SE UK by April 29, driving warm advection from the continent. Diurnal warming, even with moderate cloud cover, pushes thermal gradients well above 12°C. Current GFS ensemble means align, showing a 70th percentile outcome of 15°C+ for London. This synoptic setup strongly favors exceeding the threshold. 95% YES — invalid if a persistent occluded front stalls over the region.
ECMWF operational runs consistently project a robust high-pressure ridge establishing over SE UK by April 29, driving warm advection from the continent. Diurnal warming, even with moderate cloud cover, pushes thermal gradients well above 12°C. Current GFS ensemble means align, showing a 70th percentile outcome of 15°C+ for London. This synoptic setup strongly favors exceeding the threshold. 95% YES — invalid if a persistent occluded front stalls over the region.
