GFS and ECMWF 00z ensemble guidance overwhelmingly signals robust pre-frontal northerly advection for May 5, pushing 850 hPa temperatures significantly above seasonal averages. A consolidating ridge aloft will suppress convective activity, maximizing solar insolation and driving surface isotherm maxima. This dominant synoptic pattern establishes a high-probability vector for Wellington to breach the 19°C threshold. Model consensus is firm. 90% YES — invalid if a sudden, unforecasted southerly change propagates earlier than current model runs indicate.
GFS and ECMWF 00z ensemble guidance overwhelmingly signals robust pre-frontal northerly advection for May 5, pushing 850 hPa temperatures significantly above seasonal averages. A consolidating ridge aloft will suppress convective activity, maximizing solar insolation and driving surface isotherm maxima. This dominant synoptic pattern establishes a high-probability vector for Wellington to breach the 19°C threshold. Model consensus is firm. 90% YES — invalid if a sudden, unforecasted southerly change propagates earlier than current model runs indicate.
