South America Calling

More Limited Central Brazil Rainfall

John Baranick
By  John Baranick , DTN Meteorologist
Isolated showers over central Brazil will keep precipitation well-below normal for the next week. (DTN graphic)

Going into mid-December, the rainfall totals in Brazil have offered little more than short-term benefit in many crop areas. Scattered showers have meandered from southern Brazil to central Brazil and back again during the last few weeks.

Normally, this would produce some more uniform positive conditions over the country, with soaking rains every other week over the majority of the growing regions filling soils, followed by sunny weather for good photosynthesis and back to soaking rains.

However, the rains that have come have been underwhelming. Rainfall amounts over Brazil during the last 30 days have been a meager 20-50% of normal for almost the entire country outside of Parana into northern Rio Grande do Sul, which is closer to normal.

The forecast continues to feature precipitation over the country. This week it will be focused toward southern areas, migrating to central and northern areas late this weekend into next week. The showers will be near- to above-normal amounts in the Parana area, but over the north, the showers will be more scattered with lower-than-normal amounts. In fact, the picture looks a lot like the past 30 days, with normal to above-normal precipitation amounts around Parana and much less over central growing regions.

Despite amounts likely to be below normal, the timeliness of the showers will be important. Showers continue to be of the scattered nature, leaving some areas out while others receive more than forecast. But even below-normal precipitation will help stave off stress to corn and soybeans entering or moving through reproduction. It will not be able to build soil moisture for stretches of dryness, but at least keep the situation from getting worse.

Argentina has had somewhat similar conditions. Rainfall during the past 30 days has been below normal for most of the country outside some of the production areas in the northeast where it has been closer to or above normal.

It has not been as dire as Brazil, however. This week is a bit drier, though a deluge is possible for Dec. 17-18 where modeled estimates of 30-60 millimeters (1.2 to 2.4 inches) are forecast during a 24-hour period for a major swath of the corn and soybean producing areas. That precipitation will be very important as developing corn and soybeans moves toward reproduction in fair to poor shape thus far.

The forecast is a little more ominous for both countries for the following week. La Nina, which DTN has been talking about regularly during the past several months, leads to below normal precipitation for Argentina and southern Brazil, with more normal precipitation for central Brazil. At least for one week, this pattern looks to take hold. Precipitation in the current week will be necessary for enduring the dryness next week.

For central Brazil, a return to normal precipitation would be a huge benefit to a crop that is stressed and may be damaged across a wide area due to the below-normal precipitation. More above-normal precipitation will be needed as we head into the new year and the thoughts on the safrinha season start to take shape.

John Baranick can be reached at


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