03/15/2023, 3:26 pm EDT

South America Month 1-3 Outlook: Argentina drought roars on; Northeast Brazil is mostly wet.

Executive Summary: The Climate Impact Company month 1-3 ahead climate outlook valid for Q2/2023 is based on an ENSO shift from La Nina toward El Nino and presence of marine heat waves either side of the coastlines. The outlook maintains Argentina drought and attendant anomalous warmth for another couple months. Northeast Brazil turns very wet. Climate: Changes in the prevailing climate patterns are expected during 2023. First and foremost, ENSO phase is forecast to shift to El Nino by most forecast models during MAY/JUN. The projection is made during the ENSO springtime prediction barrier (SPB) when ENSO forecast skill is historically low. Consequently, forecast confidence in the rapidly oncoming El Nino for mid-year is below average. Current ocean climate diagnostics indicate neutral Nino SSTA, a dramatic warming of the eastern equatorial Pacific subsurface, and a likely shift into negative phase southern oscillation index (-SOI) all implying an El Nino trend. Newly essential to South America climate, is the influence of marine heat wave’s (MHW) either side of South America in the middle and subtropical latitudes. The Argentina MHW has been the most dominant and is well-correlated to anomalous high-pressure ridging as observed during the just-finished summertime. The MHW off the West Coast of South America was an exception and a possible early sign that ENSO would begin a phase change away from La Nina and toward El Nino. April 2023: The CIC-CA forecast projects a high-pressure ridge across Argentina in-between upper trough patterns offshore the South America continent. As a result, more anomalous warmth and dryness will dominate the Argentina drought area and into Southeast Brazil during April. The wet zone is to the north and fueled by warmer than normal southern equatorial trade winds. The forecast has changed very little since the last update. Fig. 1-2: Climate Impact Company April 2023 constructed analog temperature and precipitation anomaly forecast for South America.  May 2023: A similar upper air set-up is in-place for May. The upper-level ridge stretches across Northern Argentina while a deep trough is near the far southern coast of South America. The sensible weather features more anomalous warmth across central and northern portions of Argentina. Wet weather is locked-in across Northeast Brazil arcing into Northern Argentina. The wet weather focus is across the core of the Argentina drought zone. Fig. 3-4 Climate Impact Company May 2023 constructed analog temperature and precipitation anomaly forecast for South America. June 2023: The upper ridge pattern is weaker but still resides across North-central Argentina as meteorological winter begins. The forecast produces marginal warmth in Argentina with chilly risk from East Bolivia to the coffee growing areas in Southeast Brazil. Dry climate persists across Northeast Argentina, Uruguay, and far Southeast Brazil while wet weather stretches east of Paraguay. Fig. 5-6: Climate Impact Company June 2023 constructed analog temperature and precipitation anomaly forecast for South America.