10/27/2022, 2:50 pm EDT

South America Season 1-3 Ahead Outlook: Brazil develops a dry climate.

Executive Summary: The Climate Impact Company season 1-3 ahead climate outlook is updated. The outlook is based on regional SSTA patterns and their (historic) correlating upper-air patterns. La Nina peaks during November, fades to neutral phase early in 2023 and may shift to El Nino late next year. The most impressive contributor to the forecast is the elongated subtropical ridge in the southern hemisphere in response to warm SSTA in this region. The result in South America is the return of a drier climate to Brazil for upcoming summer. Climate discussion: The South America season 1-3 ahead climate forecast is based on regional SSTA observations, trend and forecasts. Included are ENSO, anomalous “warm blobs” either side of the South America continent, the likely re-emergence of the Amundsen Sea cool pool and a trend toward neutral tropical South Atlantic (TSA) index. ENSO: A third spike in La Nina intensity during the 2020-22 3-year cold ENSO episode is occurring now. A potential contributor to the 3rd spike is emergence of negative Indian Ocean dipole (-IOD) north and northwest of Australia. The Australia Bureau of Meteorology (ABOM) confidently projects -IOD to end during early 2023. The ENSO regime is likely to mirror the IOD phase change by also shifting to neutral phase during quarter 1 of 2023. Most dynamic models and the Climate Impact Company constructed analog (CIC-CA) project neutral ENSO developing during Q1/2023. The CIC-CA forecast projects a 2-in-1 chance of El Nino later in 2023. The New Zealand “warm blob”: Of interest is the titanic warming projected by the IMME model of southern latitude subtropical SSTA across the Indian Ocean, Pacific Ocean and South Atlantic. Part of that vast warm SSTA region is the New Zealand “warm blob” stretching across the South Pacific to the east of Australia. Presence of the warm SSTA in the subtropics raises the risk of drought-producing high-pressure ridge areas if they extend over a land mass. Argentina “warm blob”: The large area of warm SSTA off the East Coast of Argentina is expected to widen and intensify during the summer season. As a consequence, risk of a drought-producing high-pressure ridge extending across central and southern South America increases. Tropical South Atlantic index: When surface water is warmer than normal in the South Atlantic tropics, trade winds can force higher low-level atmosphere moisture into Brazil causing excessive rainfall. Most forecast models are indicating neutral TSA ahead. Amundsen Sea cool pool: Typical of the past 3 years especially during the warm season a large mass of anomalous cool SSTA centered on the Amundsen Sea well southwest of South America. There is a tendency for a low-pressure trough to form over this cool SSTA zone sometimes extending to the South America continent. During summer, the Amundsen Sea trough may stay closer to the Antarctic continent allowing the eastward extension of the New Zealand “warm blob” ridge to amplify and contribute to South America dry climate risk. Current soil moisture anomalies and trend: Currently, most of Argentina is encountering worsening drought while Central Brazil dryness has also strengthened. Unlike last year, a wet climate has soaked soils in southwest and southeast portions of Brazil. Fig. 1: Current global SSTA analysis and regions of influence on South America climate. Fig. 2: IMME global SSTA forecast for Q1/2023 and regions of influence on South America climate. Fig. 3: The Climate Impact Company constructed analog Nino34 SSTA forecast reveals La Nina weakens and El Nino may develop later next year. Fig. 4: South America daily soil moisture anomaly analysis and trend in key crop areas. Fig. 5: The CIC-CA 500 MB anomaly forecast for DEC/JAN/FEB 2022-23 identifies an elongated subtropical ridge across a vast warm SSTA zone. November 2022: A wet climate forecast is indicated for late spring across most of Brazil plus central to eastern Argentina. The wet weather will ease drought concerns in Central Brazil and temporarily suppress drought in Argentina. Dryness continues and strengthens in Southeast Brazil to Uruguay where warmer than normal temperature is expected for late spring. Fig. 6-7: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for November 2022. DEC/JAN/FEB 2022-23: Despite soaking wet soils spread across southwest and interior southeast Brazil, the summer outlook for this region is dry and due to the lengthy dry pattern expected, late warm season drought is possible in some areas that enter the summer season with reasonable to excessive soil moisture. Anomalous heat to accelerate the effectiveness of a dry climate on soil moisture loss is centered over Paraguay and vicinity. Essentially, a similar zone to last summer is forecast to redevelop a dry summer pattern again this year. Preceding summer 2021-22 the Southeast Brazil sector was already dry. This year, far southern Brazil is dry but areas due east of Paraguay are wet. So…a potential drought scenario for summer 2022-23 is not as intense for Southeast Brazil but certainly possible. North/Northeast Argentina is also likely to maintain drought while East Argentina to the south of Uruguay gains a wet weather pattern.  Fig. 8-9: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for DEC/JAN/FEB 2022-23.  MAR/APR/MAY 2023: A complete breakdown of La Nina is projected for autumn 2023. As a result, a dry climate is projected across Brazil while the Paraguay drought reverses due to a wet regime. The Brazilian climate is also warmer than normal. Northeast/East Argentina turns drier while much of Argentina is cooler than normal for the autumn season. Fig. 10-11: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for MAR/APR/MAY 2023. JUN/JUL/AUG 2023: The initial forecast for next winter indicates a cold risk in the Brazilian coffee-growing areas while to the north and also far southeastern Brazil are warmer than normal. Southeast Brazil is unusually dry during the winter season. Fig. 12-13: The Climate Impact Company constructed analog forecast of temperature and precipitation anomalies valid for JUN/JUL/AUG 2023.