FXUS20 KWBC 021946

PMDSA 



South America Forecast Discussion - International Desks

NWS Weather Prediction Center College Park MD

246 PM EST Mon Feb 02 2026



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



Forecast Bulletin 02 February 2026 at 1945 UTC:



On Monday, deep convection is expected over much of the tropical

portion of South America as moisture is converging over portions

of Brasil, Bolivia, Peru, Ecuador, and south Colombia. In the

upper levels of the atmosphere, the Bolivian High is dominating

the region, favoring convection over a large portion of the

continent. In part, associated with the positive phase of the

Antarctic Oscillation, expect upper level troughs to remain to the

south, limiting any northward propagation of frontal boundaries in

the lower levels. As such, much of the precipitation over the

tropical region will be affected by the diurnal cycle. In

addition, the region is experiencing close to seasonal and above

normal amounts of precipitable water, particularly in portions of

southeast Brasil and along the foothills of the Andes Mountains in

Peru and Bolivia. Of note on Monday, a shortwave upper level

trough is propagating over northern Argentina, bringing unstable

conditions from central Bolivia, Paraguay, and into southern

Brasil. By activating the South American Low Level Jet, enhanced

moisture advection into these regions will favor heavy

precipitation and deep convective conditions on Monday. The

Pantanal region of Brasil can expect maxima of 50-100mm,, while

the Parana Basin can expect maxima of 40-80mm. From the Selva Alta

in Peru through the Yungas in Bolivia expect maxima of 35-70mm.

Similar totals are expected in northern Peru, Rio de

Janeiro/Espirito Santo, and across Mato Grosso and Tocantins due

to significant moisture convergence in the lower levels. On

Tuesday, these condition are expected to continue in south Brasil

and along the foothills of the Andes Mountains, while dry air is

advected into northeast Brasil. With this decrease in moisture to

the north, expect moisture to converge in regions that will

already see heavy precipitation on Monday. The Cerrado region can

expect maxima of 35-70mm, while the Pantanal can expect maxima of

40-80mm. The southern portion of Brasil can expect generalized

maxima of 25-50mm, with a potential for localized higher amounts.

Along the Selva Alta and the Yungas, the advection of moisture

along the SALLJ will continue to interact with the terrain and

favor maxima of 35-70mm on Tuesday. By Wednesday, a retrograding

upper level trough enters the eastern Brasil region, interacting

with the Bolivian High and assisting with the advection of drier

air into the region from the Central Atlantic. With this upper

trough, the presence of the Bolivian High weakens over east

Brasil, favor lower precipitation totals on Wednesday from

Tocantins through the Cerrado region and into the Serra do Mar

region. the heaviest precipitation is expected from the Pantanal

through the Parana Basin as the upper level trough that came from

Argentina has now entered south Brasil, providing unstable

conditions. However, with the decrease of moisture in the region,

expect maxima of 30-60mm. to the north, similar totals are

expected as low level moisture converges over the northwest Amazon

Basin.



To the south, weak upper level troughing remains over the

Patagonia and south Chile. With the presence of the Bolivian High

blocking further northward movement, most frontal boundaries

crossing from south Chile are expected to weaken over the central

portions of Argentina. However, the presence of the SALLJ to the

north will favor moisture advection into central Argentina,

favoring moderate precipitation over the next several days. In

addition, frontal boundaries and troughing will favor lift in the

lower levels, and the upper level troughs increase the instability

in the region. On Monday, expect maxima of 15-20mm in the Sur

region of Chile into the northern Austral region. On Tuesday,

moisture converging along a passing front in the Cuyo/Cordoba

region, expect maxima of 20-35mm, similar amounts are expected in

the southern Patagonia. On Wednesday, expect maxima of 20-45mm in

La Pampa region.



Castellanos...(WPC)





$$