South America Forecast Discussion - International Desks NWS Weather Prediction Center College Park MD 225 PM EST Wed Feb 12 2025 GFS data at ftpprd.ncep.noaa.gov/data/nccf/com/gfs/prod/ South America Forecast Bulletin 11 Feb 2025 at 1930 UTC In Mid - Latitude South America... In north Argentina, Uruguay, and south Brasil, a surface cold front, located across south Uruguay and northern Argentina on Wednesday afternoon, will transition into a stationary front by Friday evening and will be located across north Uruguay and southern Brasil and decaying thereafter. The greatest precipitation impacts will occur from Wednesday morning through Thursday morning. A mid-level shortwave trough will be traversing this region Wednesday afternoon through the evening. We will also see an increase in low level moisture convergence and upper divergence in this same time span. Thus, convection will be more favorable starting Wednesday afternoon through Thursday morning, yielding to maximum precipitation totals of 30 - 60mm in northeast Uruguay and Rio Grande do Sul. Expect maximum precipitation totals of 20 - 35mm in parts of Rio de la Plata and Cordoba-Santa Fe regions of Argentina for this same time period. By Thursday morning through Friday morning, the moisture coupled with the stationary front will rapidly propagate northward into southeast Brasil, where upper divergence and moisture continue to be plentiful. This will yield to maximum precipitation totals of 25 - 50mm for Thursday morning through Friday morning along this region. Other systems of interest in Argentina and Uruguay are a series of low level troughs affecting the region after Thursday morning. From Thursday morning through Friday morning, a low level trough will drape across central Argentina and into southern Uruguay. In the mid-levels, expect a shortwave trough with accompanied vorticity advection and a subtle increase in low level moisture after Thursday afternoon and into the overnight hours. A cooling of the mid-levels will yield to an increase in instability, with slight risk severe weather possible across Cordoba - Santa Fe, La Pampa-Buenos Aires Province, and Rio de la Plata. Expect maximum precipitation totals of 15 - 25mm in the Cordoba - Santa Fe province and La Pampa - Buenos Aires Province for Thursday morning through Friday morning. By Friday morning through Saturday morning, another trough across northern Cordoba - Santa Fe will yield similar conditions in the region, and anticipate maximum precipitation totals of 20 - 40mm for Friday morning through Saturday morning. Elsewhere, in Chile, expect daily maximum precipitation totals of 15mm for the next three days. A series of upper level troughs and surface fronts will continue to drive moisture plumes into the coast of Austral Chile. In Tropical South America... In the upper levels, a more easterly flow is expected to develop over the region, and will favor an increase in speed divergence and diffluence through Saturday morning. Areas most impacted by this regime will be Ecuador and the Amazon Basin, where an abundance of moisture convergence will prevail through Friday morning. These conditions will yield to maximum rainfall totals of 35 - 70mm for east-central Peru from Wednesday morning through Thursday morning. By Thursday morning through Friday morning, the effects of upper divergence will be greater over the region, though moisture convergence will decrease by late Thursday evening across Ecuador and the west Amazon Basin. Expect a maximum precipitation total of 35 - 70mm to span across parts of the northwest and west Amazon Basin for Thursday morning through Friday morning. Anticipate a drying trend thereafter over this region. By Friday morning through Saturday morning, areas of greatest precipitation impact will be across the central Amazon Basin, with maximum precipitation totals of 25 - 50mm will be likely. In Ecuador, the aforementioned upper level regime and low level moisture will be the main driving force for precipitation patterns in the next three days. Expect the highest maximum precipitation totals of 30 - 60mm for Wednesday morning through Thursday morning. In the low levels, though a more southerly wind flow will begin to impact the coast, the ITCZ will continue to favor moisture convergence in this region. Do expect a subtle daily decrease in maximum precipitation totals. Another region of interest is east-central Bolivia starting Thursday morning. An upper trough situated across central Bolivia Wednesday afternoon will remain semi-stationary over this region through the next three days. The trough will favor upper diffluence while the low level moisture convergence will be present starting Thursday afternoon through Friday afternoon. Highest maximum precipitation totals of 25 - 50mm are expected for Thursday morning through Friday morning in central Bolivia. Elsewhere in tropical South America, the ITCZ, NET, and Southern ITCZ will continue to be of influence in precipitation patterns across the region. Do note that the Atlantic Southern ITCZ will lose its definition by Friday morning into Saturday morning. Also, a series of low level troughs will help enhance precipitation chances in the northeast regions and across the central-southeast coast of Brasil. Morales...(WPC) Castellanos...(WPC)