The following content was provided by meteorologist Gail Martell of MartellCropProjections.com:
Argentina Drought Easing, Crop Damage Incurred
Severe drought in Argentina has eased with strong showers recently in the top farm provinces. A three-week stretch of intense heat and dryness is giving way to showers as a cool front pushes northward through the Argentina grain belt. Buenos Aires, the top farm province, has already received generous rainfall in excess of 1 inch (25 millimeters).
Cordoba, a key corn area, also received scattered heavy rain on Saturday night from a cluster of strong thunderstorms. Up to 3 inches of rain occurred. Still dry, the northern third of the Argentina soybean belt is expecting soaking rainfall with a north-moving cool front. Around 1 - 1.5 inches of rain is predicted in soybean areas of Santa Fe, upper Cordoba and Chaco.
Temperatures were 8-10 degrees F above normal in the 2 weeks leading up to Christmas at Marcos Juarez, a key corn area in eastern Cordoba. Highs in the upper 90s to near 100 F were common.
South Brazil Expecting Heavy Rain
Rio Grande do Sul and Parana, Brazil's 2 key southern farm states have been subject to strong drying in December. However, temperatures have been less extreme than Argentina, especially Parana.
A large stable ridge of high pressure in the western Atlantic Ocean has produced subsiding winds onshore that dry out the atmosphere, stifling rain showers. Dryness in Parana became severe, hardly any rain occurring in the 15 days leading up to Christmas. In a typical December, showers are abundant, 1.65 inches weekly in Brazil's second leading farm state.
The temperatures in Parana have been moderated by cool ocean breezes. Daily maximum temperatures have been mostly mid 80s F in December, a result of moderating from the Atlantic Ocean high pressure system. Western Parana has been hotter, occasionally experiencing highs in the 90s F.
Rio Grande do Sul , Brazil's southern farm state, was less affected by cool high pressure experiencing hotter growing conditions. Highs in the mid-upper 90s F have been rather common in recent weeks. Moreover, drought intensified recently, though previously, in early December growing conditions were ideally wet.
Very heavy rainfall is now predicted Brazil's two southern farm states, 3-4 inches based on the 7-day GFS model. The forecast is wetter in southern Brazil than Argentina.
In summary, Argentina weather stress has been far worse than South Brazil due to hotter temperatures in the recent 2 weeks. In addition Argentina crops were planted on a delayed timetable and thus have a shallow a root system. This may lead to unusually severe moisture stress.