ECMWF 00Z runs show 700mb geopotential heights supporting persistent warm advection over Shanghai. Boundary layer forecasts consistently model Tmin in the 15-17°C range for May 5th. This 13°C threshold represents a 1.8°C negative anomaly from the 10-year mean Tmin and sits beyond the current 2-sigma spread of major ensemble forecasts, indicating low probability. Radiative cooling insufficient for such a drop. 95% NO — invalid if a significant cold air mass advection is identified in subsequent 12Z model runs.
ECMWF 00Z runs show 700mb geopotential heights supporting persistent warm advection over Shanghai. Boundary layer forecasts consistently model Tmin in the 15-17°C range for May 5th. This 13°C threshold represents a 1.8°C negative anomaly from the 10-year mean Tmin and sits beyond the current 2-sigma spread of major ensemble forecasts, indicating low probability. Radiative cooling insufficient for such a drop. 95% NO — invalid if a significant cold air mass advection is identified in subsequent 12Z model runs.
