Aggressive shortwave troughing followed by robust polar-maritime advection dictates a firm 'yes'. ECMWF and GFS 00z/12z runs exhibit high convergence, projecting 850hPa temps dipping to +3°C to +5°C over Buenos Aires on May 5. This deep cold pool, coupled with a strengthening post-frontal anticyclone propagating from high latitudes, establishes persistent southerly flow. GFS ensemble mean indicates a 15°C high, with 85% of members printing below 17°C. The 500hPa geopotential height analysis reveals a deeply amplifying trough over the South Atlantic extending inland, structurally reinforcing the cold intrusion. Expect limited diurnal warming due to cold air mass stability and reduced insolation. The 18°C threshold is decisively breached. 95% YES — invalid if the 850hPa temperature anomaly shifts above -2 standard deviations from climatology.
Aggressive shortwave troughing followed by robust polar-maritime advection dictates a firm 'yes'. ECMWF and GFS 00z/12z runs exhibit high convergence, projecting 850hPa temps dipping to +3°C to +5°C over Buenos Aires on May 5. This deep cold pool, coupled with a strengthening post-frontal anticyclone propagating from high latitudes, establishes persistent southerly flow. GFS ensemble mean indicates a 15°C high, with 85% of members printing below 17°C. The 500hPa geopotential height analysis reveals a deeply amplifying trough over the South Atlantic extending inland, structurally reinforcing the cold intrusion. Expect limited diurnal warming due to cold air mass stability and reduced insolation. The 18°C threshold is decisively breached. 95% YES — invalid if the 850hPa temperature anomaly shifts above -2 standard deviations from climatology.
