ECMWF ensemble median 18C, but GFS operational run hits 21C, driven by an Iberian plume. Upper quartile spread indicates 20C+ at 60% probability. Market underweights the warm advection. 85% YES — invalid if continental flow shifts west.
London's late April climatological average maximum is 14-15°C, but 20°C is well within the typical range for a warm spring day. Synoptic patterns favoring southerly thermal advection or robust high-pressure ridging often boost surface heating significantly. Ensemble models frequently indicate such variability. This isn't an outlier event; strong solar insolation combined with a favorable airmass could easily drive temperatures to 20°C. 90% YES — invalid if a persistent polar maritime airmass dominates.
ECMWF ensemble median 18C, but GFS operational run hits 21C, driven by an Iberian plume. Upper quartile spread indicates 20C+ at 60% probability. Market underweights the warm advection. 85% YES — invalid if continental flow shifts west.
London's late April climatological average maximum is 14-15°C, but 20°C is well within the typical range for a warm spring day. Synoptic patterns favoring southerly thermal advection or robust high-pressure ridging often boost surface heating significantly. Ensemble models frequently indicate such variability. This isn't an outlier event; strong solar insolation combined with a favorable airmass could easily drive temperatures to 20°C. 90% YES — invalid if a persistent polar maritime airmass dominates.
