South America Forecast Discussion - International Desks
NWS Weather Prediction Center College Park MD
310 PM EST Mon Feb 09 2026

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

Forecast Bulletin 09 February 2026 at 1930 UTC:

Over the tropical region of South America, the main drivers of
precipitation throughout the forecast period will be moisture
advection, low-level moisture convergence, diurnal heating,
orographic lifting, and other local effects.

Daily accumulations of 20-35mm are expected over the Pacific coast
of Colombia and Ecuador throughout the forecast period as  deep
moisture is advected from the Pacific Ocean into the region.
Although there is enough moisture to produce heavy precipitation
in the area, the low-level winds are anticipated to be mostly
parallel to the coast and relatively weak, which will limit
precipitation in the area.

In Brazil, the heaviest precipitation from today through Wednesday
will be associated with the presence of the SACZ. Low-level
moisture convergence will be the main driver of rainfall and
thunderstorm development. Additional enhancement in upper-level
divergence is anticipated with the presence of the Bolivian High
and an upper-level trough over southern Brazil enhancing
diffluence along the confluence at lower levels. For today through
Tuesday, the highest rainfall accumulations are expected to be
around 30-75mm over the Parana Basin, extending into Mato Grosso.
An additional 30-60mm of rainfall is likely from Tuesday through
Wednesday. The SACZ is then expected to decay by Wednesday,
resulting in a decrease in precipitation from Wednesday through
Thursday.

Another region of interest  in Brazil over the next three days is
the Amazon Delta region, where the presence of a plume of moisture
associated with a low-level trough propagating westward will
enhance low-level moisture convergence and support the development
of heavy rainfall. By the end of the forecast period, as the
low-level trough propagates, precipitation is expected to increase
in the Guianas. Daily accumulations of 20-45mm are forecast for
the region, with higher isolated totals likely. An enhancement in
upper-level divergence is anticipated from Wednesday through
Thursday, resulting in higher accumulations. Totals are likely to
be around 30-60mm.

Heavy rainfall is anticipated from Tuesday through Wednesday for
Peru, particularly over the southwest Amazon region into Selva
Alta, and portions of Bolivia. This precipitation will be
associated with the presence of an upper-level shortwave trough
moving across the region. Additional support is likely due to
mid-level troughing. With high precipitable water available in the
area, maximum accumulations could reach 40-80mm.

The development of a cold front on Tuesday will bring heavy
rainfall and thunderstorms mainly over Argentina, particularly in
La Pampa, Buenos Aires, and the Mesopotamia region from Tuesday
through Thursday as the frontal boundary propagates. Upper-level
support is expected for the development of deep convection in the
region with the presence of a jet at upper-levels and mid-level
diffluence. The development of thunderstorms over the Buenos Aires
and Mesopotamia regions and portions of Uruguay is expected to
happen late on Tuesday through Wednesday morning. Heavier
precipitation is anticipated for Uruguay, Mesopotamia, Cordoba and
Santa Fe, as low-level moisture convergence increases with the
presence of the frontal boundary. Accumulations are forecast to
reach 40-80mm with a risk of severe weather.



Rivera-Torres...(WPC)