Argentina Generous Rains Possible Next Week, Tricky Forecast

January 27, 2012

The Buenos Aires Cereals Exchange still has high hopes for Argentina soybeans, while lowering expectations for corn production.   The new soybean estimate is 46.2 million metric tons, a mere 2% below last year.  The new corn estimate is 22 million metric tons, down 8-9% from the previous peg 24 million metric tons.

The recent rainfall was “just in time” for soybeans the Exchange said.    Soybeans received anywhere from 1.5 to 3  inches of rainfall  of rainfall in the past 2 weeks,  improving topsoil moisture. 

The optimistic view on soybeans may not be warranted.   The subsoil is still very dry from extremely low rainfall previously.   It would not take long for the topsoil moisture to get used up,  particularly if temperatures continue hot,   keeping evaporation high.  Drought stress may resume in shallow-rooted soybeans,  unless the heavy rainfall keeps coming.  

Rio Cuarto, Cordoba, received nearly 3 inches of rainfall in the past couple of weeks, but the deep soil layer is still dry.   December was an incredibly  dry month with less than one-third of normal rainfall.   Rainfall recently was very generous; in fact, one of the wetter areas in the Argentina corn belt.

 

Temperatures have maintained above normal in eastern Cordoba, though not nearly as hot as before:

 

Forecast Update

Windy and very warm conditons are predicted on the weekend in the Argentina central grain belt.   Marcos Juarez Cordoba will be 90 F tomorrow, followed by 93 F, 95F and 93F  Sunday through Tuesday.  A few showers are expected Monday (a 40% chance) and Tuesday (a 20% chance.)

The GFS model calls for scattered rains,  mostly .50 - .75 inch,  in the Friday-Tuesday time frame.  See where corn and soybeans are grown. 

 

Temperatures would be above normal over 90 F in the main soybean growing areas:

 

Trough of Low Pressure Developing

A weak cool front is expected to arrive in the central grain belt  Sunday night setting off scattered showers.  Rainfall is expected to be rather variable and light to begin with.       However, recurring showers are expected to continue into the middle of next week in an unstable trough of low pressure. 

Once again we are looking at a forecast for potentially heavy rainfall beyond the 5-day window, when reliabiability on predictions diminishes.  Below see the weekly rainfall outlook incorporating generous rains the middle of next week.

All the while, south Brazil is expected to remain  dry under the influence of high pressure.  The normal weekly rainfall  in Rio Grande do Sul  and Parana in mid summer is from 1.2 to 1.65 inches.

 

Stable high pressure will keep Argentina dry today.  See the surface weather map valid this evening:

 

By Sunday evening High Pressure would be receding east into the Atlantic Ocean, allowing a weak trough of low pressure to develop in  the Argentina western grain belt.  A few scattered howers are predicted.

 

Rainfall is possible by Monday evening.  Rainfall amounts may vary from light to heavy.  

 

The Wednesday evening forecast still shows low pressure parked over the Argentina grain belt.  This forecast shows potentially heavy rain.  Though the trough of low pressure appears weak, it would keep a presence in Argentina for a few days,  encouraging recurring showers.