The Dominance of Regional SSTA Patterns on South America Climate 

March 2023 Global Soil Moisture Observations and Outlook
03/09/2023, 8:40 am EST
Strong Madden Julian Oscillation Ends La Nina
03/12/2023, 12:49 pm EDT
Show all


Fig. 1: ECM ENS 15-day upper air pattern across South America featuring the semi-persistent upper-level high pressure ridge across the marine heat wave east of Argentina and opposing upper trough extending northward from the Amundsen Sea cool pool.

Discussion: A common regime is featured in today’s 15-day upper aur forecast for South America by the ECM ENS (Fig. 1).  An amplified upper-level high-pressure ridge anchors off the Argentina Coast and is compensated for by a similarly impressive deep low-pressure trough west-southwest of Chile. Note that weak low pressure appears in the vicinity of Northeast Brazil. The low pressure in that region is associated with enhanced vertical currents associated with convection inspired by a transient phase_8 to phase_1 transition of the Madden Julian oscillation (MJO). The increasing rainfall generated across Brazil will shift southward along the west side of the offshore high-pressure system surging into Argentina just-after mid-month but mostly missing the Northern Argentina drought area. Latest daily SSTA analysis reveals the long-standing SSTA regime of the marine heat wave east of Argentina and Amundsen Sea cool pool extending northeastward from the Antarctic home base (Fig. 2-3).

Fig. 2-3: Semi-permanent regional SSTA patterns influencing South America climate persist. The marine heat wave east of Argentina and the northward extension of the Amundsen Sea cool pool.