Seoul's climatological normals for late April establish mean daily highs around 18-20°C. A -14°C maximum represents an extreme negative temperature anomaly exceeding 30°C, demanding unprecedented deep polar advection and persistent severe radiative forcing incompatible with seasonal synoptic patterns. This data point is multiple standard deviations outside the historical distribution, signaling a meteorological impossibility for this period. Current forecast ensemble runs show no such extreme. 100% NO — invalid if all global numerical weather prediction models simultaneously predict a -30°C 850hPa anomaly over Korea.
