ECMWF 00z operational run and GFS ensemble means for May 10 indicate London's 850 hPa temperatures will be insufficient for a 20°C surface maximum. The prevalent synoptic setup features a moderate zonal flow, precluding strong continental advection or optimal boundary layer heating from insolation under a dominant anticyclone. Diurnal thermal gradient projections consistently remain below the 20°C threshold, signaling a sustained cooler pattern. 90% NO — invalid if a persistent high-pressure cell anchors over the near continent, driving strong southerly advection.
ECMWF 00z operational run and GFS ensemble means for May 10 indicate London's 850 hPa temperatures will be insufficient for a 20°C surface maximum. The prevalent synoptic setup features a moderate zonal flow, precluding strong continental advection or optimal boundary layer heating from insolation under a dominant anticyclone. Diurnal thermal gradient projections consistently remain below the 20°C threshold, signaling a sustained cooler pattern. 90% NO — invalid if a persistent high-pressure cell anchors over the near continent, driving strong southerly advection.
