Short-range ECMWF 00z and GFS 06z ensemble guidance indicates a high probability for Wellington's max temperature on April 27 to hold around 16.5°C, with minimal thermal advection due to a persistent weak southerly flow. The tight ensemble spread, combined with a transient upper-level shortwave, presents no significant synoptic forcing for adiabatic warming. The market overestimates the probability of breaching 17°C.
