Ensemble guidance from both GFS and ECMWF operational runs strongly rejects a sub-23°C high. 850hPa isotherm analysis consistently projects peak surface temperatures between 26-28°C for Chengdu on May 5. This indicates robust thermal advection and favorable boundary layer mixing, pushing well above the 23°C threshold. 90% NO — invalid if a sudden, unforecasted meridional shortwave disrupts prevailing zonal flow, inducing significant cold advection or persistent cloud cover.
Ensemble guidance from both GFS and ECMWF operational runs strongly rejects a sub-23°C high. 850hPa isotherm analysis consistently projects peak surface temperatures between 26-28°C for Chengdu on May 5. This indicates robust thermal advection and favorable boundary layer mixing, pushing well above the 23°C threshold. 90% NO — invalid if a sudden, unforecasted meridional shortwave disrupts prevailing zonal flow, inducing significant cold advection or persistent cloud cover.
