03/19/2023, 1:44 pm EDT

AG Market Sunday Global Weather/Climate Report: Where are the current drought areas? 2-week outlooks into early April.

Fig. 1: The standardized precipitation index (SPI) is regarded as the best drought indicator index. The 12-monthe SPI as of FEB-23 identifies current drought areas. Discussion: As Q1/2023 closes, global drought areas as defined by the 12-month standardized precipitation index (SPI) are most heavily biased toward the Americas (Fig. 1). The primary catalyst of drought dominating both South and North America during recent years is the combined influence on climate by a La Nina climate and tendency for very warm SSTA in the mid-latitude oceans. Generally, this combination has produced a wet effect across Asia to Australia and Africa while North and South America to parts of Europe have been dry. During 2023, ENSO is forecast to shift into El Nino while mid-latitude SSTA patterns stay ferociously warm. Certainly, the dry/drought regions are likely to increase in the eastern hemisphere and possibly weaken in the western hemisphere if El Nino is reasonably strong as many dynamic models indicate. Currently, drought is dominating South America. Long-term drought continues in Chile while the strongest new drought of 2022-23 evolved over Argentina. Strong dryness persists in Bolivia to Ecuador and is evolving in Central Brazil. In North America, drought is strongest in the central Great Plains to Texas and across northeastern Mexico. Dryness is evident across much of the Canadian Prairies and parts of the Ohio Valley. Of interest is the ED4 classification across the North-central to Northeast portion the U.S. as defined by evaporative drought demand index (EDDI) which implies this sector is “thirsty” for moisture (Fig. 2). Fig. 2: Evaporative drought demand index (EDDI) is useful as a predictor of future drought or flash drought. Elsewhere, drought is regenerating in France to Italy, Western Turkey and the western portion of the Black Sea region, and parts of the eastern Africa tropics. Northeast India and East-central China drought continue while Interior Southwest Australia is also encountering drought. Where will the northern hemisphere summer drought regions emerge? At this early look, large areas of deep layer soil moisture deficits are an early indicator as to where drought will develop if not already intact. They are: 1.) The western to central Great Plains to northwest Texas, 2.) The Carolinas, 3.) The western Black Sea region including Southern Ukraine, 4.) Iraq and vicinity plus 5.) Central China. The U.S. EDDI observations indicate a careful eye on the Northern U.S. are warranted. Highlights in the 2-week outlooks based on the just-received 12Z indicate heavy rains across the Ohio Valley with up to 5 in. possible in some spots (Fig. 3). Wet weather is also indicated for the central Great Plains. The 10-day forecast reveals a large stretch of 1-3 in. of rain across Western Europe through the Baltic nations (Fig. 4). Both the U.S. and Europe rainfall outlooks indicate needed beneficial precipitation for some of the drought areas currently intact most notably Nebraska and the northern half of France. Fig. 3-4: The 12Z GFS percent of normal precipitation forecast across the U.S. AG Belt and 10-day percent of normal precipitation forecast by GFS for Europe. Concern regarding expanding Northeast India drought is back on the table. Marginally dry soil conditions in this zone likely receive under-achieving rainfall from short-term events followed by hotter and drier medium-range forecasts which accelerate dry soils based on the latest 12Z GFS outlook (Fig. 5). In South America, more hot weather across Argentina into early next week. However, a cold front brings heavy rain in the 6-10-day period (Fig. 6) followed by a cooler air mass for the 11-15-day period. Fig. 5-6: The 12Z GFS rainfall forecast for the next 5 days across India and GFS 6-10-day percent of normal precipitation outlook for Argentina/Brazil.