Wellington's May climatology records an average maximum temperature of 15.6°C; hitting 20°C constitutes a significant positive anomaly requiring highly specific, rare synoptic conditions. Current long-range ensemble forecasts (ECMWF/GFS) for May 6 lean towards cooler westerly or southerly airflow, rather than the robust northerly advection and Fohn warming necessary to breach the +4.4°C threshold. The probability of such an extreme event is exceedingly low. Market is overpricing outlier warm scenarios. 95% NO — invalid if a strong, persistent anticyclone establishes directly east, forcing sustained northerly flow.
Wellington's May climatology records an average maximum temperature of 15.6°C; hitting 20°C constitutes a significant positive anomaly requiring highly specific, rare synoptic conditions. Current long-range ensemble forecasts (ECMWF/GFS) for May 6 lean towards cooler westerly or southerly airflow, rather than the robust northerly advection and Fohn warming necessary to breach the +4.4°C threshold. The probability of such an extreme event is exceedingly low. Market is overpricing outlier warm scenarios. 95% NO — invalid if a strong, persistent anticyclone establishes directly east, forcing sustained northerly flow.
