South America Calling         09/18 10:49

   Central Brazil May Get Widespread Rain Next Week, Likely Kicking Off Wet 
Season Rainfall

   Producers in central Brazil await the start of the wet season, which usually 
occurs in late September. A front moving through next week may bring the 
widespread rainfall that many will use to start soybean planting.

John Baranick
Staff Meteorologist

   Early planting conditions in much of Argentina and southern Brazil have been 
favorable for the last couple of weeks. But producers in central Brazil, who 
will double crop soybeans with corn or cotton during the next nine months, 
await the start of wet season rainfall after months of dryness. They may get 
their wish next week.

   Some areas of Mato Grosso, especially those in the northwest near the Amazon 
rainforest, have already seen some isolated showers developing and reported 
amounts have been in the 20- to 50-millimeter (0.8- to 2-inch) range. That 
effectively is the start of their wet season, but these locations are limited 
in area. Much of central Brazil (the states of Mato Grosso, Goias, Minas 
Gerais, Mato Grosso do Sul and Sao Paulo) have yet to see a drop of rain. A 
front that came through this week looked like it had some promise on last 
week's forecast but did not produce much of any rainfall.

   So, when the forecast is calling for something similar with another front 
moving north from Argentina for next week, there could be some skepticism. The 
front is forecast to move through Argentina during the weekend, Sept. 20-21, 
and then into southern Brazil where rainfall is forecast to be very widespread 
and heavy. Amounts over 50 mm are in the forecast in various spots of these 
areas. As the front continues into central Brazil for Sept. 22-23, showers are 
forecast to become more scattered and not all areas are likely to be hit or see 
significant rainfall.

   One limiting factor could be dew points, as the moisture in the air has been 
somewhat limited recently. However, that moisture has been increasing this week 
for those closer to the Amazon as well as across Argentina and southern Brazil. 
The front moving in could draw more of that moisture together to produce more 
widespread rainfall than models are predicting.

   However, that may not even matter. Recent forecasts have the front 
effectively stalling from Mato Grosso southeast into Minas Gerais, where 
showers would continue throughout the week. Producers waiting for that first 50 
mm of rainfall to moisten topsoils and begin soybean planting may get their 
wish.

   But it does not come without risk. Not all forecasts are calling for 
widespread heavy rainfall that the region needs to begin planting, and there 
may be some concern about dryness returning after the front finally fizzles out 
later next week.

   Should a period of dryness follow after soybeans germinate, that could 
effectively kill the crop and require replanting. Many producers wait until 
October when the rains become more consistent to plant anyway; they may choose 
to do so despite the overall good weather forecast for next week. If the 
forecast does turn drier for the end of September and into early October, it 
could mean significant planting delays or replanting, which may produce 
significant issues with the safrinha (second-season) corn and cotton crops down 
the line. This still bears watching.

   To find more international weather conditions and your local forecast from 
DTN, visit https://www.dtnpf.com/agriculture/web/ag/weather/interactive-map.

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




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