South America Forecast Discussion - International Desks
NWS Weather Prediction Center College Park MD
259 PM EST Fri Feb 06 2026

GFS data at ftpprd.ncep.noaa.gov/data/nccf/com/gfs/prod/

Forecast Bulletin 06 February 2026 at 1930 UTC:

Starting today, heavy rainfall and thunderstorms will affect the
Eastern and Central Amazon Region in Brazil. Easterly,
northeasterly flow from the Atlantic will advect deep moisture
into the region and converge over the Amazon Region. Further
support is expected with upper-level divergence increasing in the
area with an upper-level trough over eastern Brazil and the
Bolivian High favoring diffluence over the region. Precipitation
will continue over northeastern Brazil from Saturday through
Sunday with the plume of moisture continuing over the region.
Daily rainfall totals of 30-60 mm are likely, with isolated higher
amounts

The convergence of easterly winds, presence of the Bolivian High,
and a mid- and upper-level trough over southern Brazil  will aid
the development of the SACZ during the forecast period. This will
bring precipitation over southeastern Brazil into Central-West
Brazil along the area of confluence. The heaviest rainfall will
begin on Saturday, and is expected to continue throughout the end
of the forecast period. Today through Saturday expect some
precipitation associated with this over the coastal region in
Serra do Mar. Then from Saturday through Sunday precipitation will
extend over Central Brazil. The highest totals will range between
40-80mm. Heavy rainfall is expected to continue from Sunday
through Monday with persistent moisture convergence and
instability in the region, an additional 40-80mm of rainfall is
anticipated

Over northern Argentina heavy rainfall is forecasted starting
today through Saturday morning, with a shortwave mid-level trough
increasing instability and a low-level trough enhancing low-level
moisture convergence in the region. Additionally a frontal
boundary that extends into Argentina will enhance precipitable
water availability in the area. This frontal boundary is expected
to be over southern Brazil, increasing precipitation in the
region. For Argentina, a maximum of 30-60mm is expected from today
through Saturday. In southern Brazil totals are likely to reach
35mm, with isolated higher totals, as upper-level divergence
supports convective activity. A marginal risk for severe weather
exists for southern Brazil. Precipitation is anticipated to
continue from Saturday through Sunday over southern Brazil as the
frontal boundary progresses. Accumulations around 25-50mm and
slight risk of severe weather are expected.

From Sunday through Monday, an increase in low-level moisture
convergence and the presence of a mid- to upper-level shortwave
trough, will bring precipitation over Central Argentina, around
the regions of Cordoba, Santa Fe and La Pampa, with totals around
20-35mm. Thereâ€s also a slight to moderate risk for severe
weather.


Rivera-Torres...(WPC)