South America Calling

South America is still experiencing overall good weather, but models have been over-forecasting the rainfall during the last several weeks.

As I have mentioned in the last two blogs at https://www.dtnpf.com/…, precipitation across Brazil and Argentina have been good, but not great, and there are some issues with locations receiving too little rain. Crop health is still a bit on the low side as well, though there are a few rumors floating out of either Brazil or Argentina at the moment.

Dry patches continue to show up in both countries regarding soil moisture. Plots from the USDA can be found here at https://ipad.fas.usda.gov/…, show plenty of areas in both countries where soil moisture is lower than normal for this time of year. Additional satellite images found on the same page describe potential issues for soil health from Normalized Difference Vegetation Index (NDVI), precipitation and drought severity. Though improved from six weeks ago, the issues are still around.

Some of the lack of concern may be attributed to models, which have been overly optimistic in their forecasts during the last two weeks. The actual amounts have not measured up to what these forecasts have been producing. It is not by a significant portion, which is why it is not standing out in a huge way, but it is a noticeable amount.

This is happening in both the European ECMWF and American GFS models. Models are never 100% accurate on their forecasts. They overproduce in some areas and underproduce in others. But for the majority of Argentina and Brazil, they have been overproducing precipitation.

The attached images display the differences between the predicted and observed rainfall amounts. At first glance, it may seem to be pretty close. But diving into some of the details, Argentina's coverage has been off. Models were producing more precipitation in more areas than what occurred. In central Brazil, it's a little more noticeable. Widespread amounts over 50 millimeters (about 2 inches) were forecast by the ECMWF, including through the Amazon, but were much patchier in central Brazil with lower coverage of amounts over 75 and 100 mm (about 3-4 inches).

When models consistently do this, it leads to poor assumptions about the actual conditions for crops in both countries. Fewer areas are seeing rain than they need in Argentina, and patchy showers with lower amounts put more soybeans at risk of dryness in central Brazil. If patchy dryness shows up, it can be explained away by the models forecasting heavy rain, so there is no need to raise flags.

In no way am I suggesting that there are major causes for concern about the crop health situation in either Brazil or Argentina. There are still ample opportunities for rainfall in both countries over the coming weeks.

Even if precipitation is not up to par, these countries are not going through extended hot and dry periods with no rainfall at all. But the insistence that there are no weather concerns south of the Equator is unfounded.

To find more international weather conditions and your local forecast from DTN, visit https://www.dtnpf.com/….

John Baranick can be reached at john.baranick@dtn.com

(c) Copyright 2024 DTN, LLC. All rights reserved.