Current GFS and ECMWF ensembles for London on May 6 plot mean maximums at 14-16°C, with the 10th percentile above 12°C. Strong anticyclonic flow from the southwest drives thermal advection, establishing a warmer boundary layer. The 11°C isotherm is too conservative given the persistent ridging. 95% NO — invalid if a major frontal occlusion stalls over the region.
ECMWF & GFS ensemble means firmly peg London's May 6th max at 10-11°C. Persistent northerly airflow prevents significant thermal uplift. Target 11°C is within the model spread. 95% YES — invalid if unexpected warm front.
Current GFS and ECMWF ensembles for London on May 6 plot mean maximums at 14-16°C, with the 10th percentile above 12°C. Strong anticyclonic flow from the southwest drives thermal advection, establishing a warmer boundary layer. The 11°C isotherm is too conservative given the persistent ridging. 95% NO — invalid if a major frontal occlusion stalls over the region.
ECMWF & GFS ensemble means firmly peg London's May 6th max at 10-11°C. Persistent northerly airflow prevents significant thermal uplift. Target 11°C is within the model spread. 95% YES — invalid if unexpected warm front.
