Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
321 PM EDT Tue Sep 01 2026

Forecast Bulletin 01 September 2026 at 1540 UTC:

The Bahamas and Caribbean:

In the Caribbean, rainfall and convective activity are expected
today over eastern Cuba and Hispaniola, driven by upper-level
divergence paired with low-level troughing and moisture
convergence. Favorable upper- and lower-level conditions will
persist over Cuba from Wednesday through Thursday. Over
Hispaniola, upper-level divergence will increase Thursday into
Friday as an upper-level trough south of Puerto Rico moves
westward, bringing afternoon thunderstorms alongside mid-level
trough support.
For Puerto Rico, expect afternoon precipitation today due to a
mid-level trough and easterly moisture advection. A decrease in
PWAT is anticipated for the eastern Caribbean on Wednesday;
however, persistent easterly flow, diurnal heating, and local
effects will still trigger isolated showers. From Thursday through
Friday, an approaching tropical wave will increase moisture across
the Lesser Antilles, bringing more widespread rainfall.

Mexico and Central America:

Over Mexico, precipitation is expected today through Wednesday
across Baja California Sur as deep moisture is advected into the
region by Tropical Storm Marie in the Pacific. Favorable
conditions will persist through the end of the forecast period.
Accumulations will range from 15 to 25mm.  Across the Sierra Madre
Occidental, upper-level troughing and upper-level divergence,
combined with low-level moisture convergence and high values of
precipitable water availability, will support showers and
thunderstorm activity particularly today through Wednesday with
accumulations of rainfall around 25-50mm.In Central America, a
westward-propagating tropical wave will bring precipitation to
Nicaragua starting today, driven by enhanced moisture and
low-level convergence. As this wave moves along the monsoon trough
south of the region, moisture and instability will increase along
the Pacific coast, promoting low-level wind convergence over El
Salvador, western Guatemala, and coastal Chiapas, Mexico.

Tropical South America:

Across tropical South America, daily thunderstorms and rainfall
are expected through the forecast period due to low-level
convergence, orographic lift, moisture advection, and diurnal
heating, primarily impacting Colombia, Venezuela, and the
Brazilian Amazon.
Through Wednesday, the heaviest precipitation will target Colombia
and Venezuela, driven by low-level moisture advection and passing
shortwave mid-level troughs. Today, the ITCZ will also support
rainfall across northern Venezuela and Trinidad and Tobago. Heavy
rainfall is anticipated Wednesday into Thursday, mainly across
Colombia, as an upper-level trough in the Caribbean enhances
upper-level divergence.  By Thursday into Friday, main activity
will shift toward eastern Venezuela, specifically the Canaima and
Orinoquia regions, driven by persistent low-level troughing and
moisture transport.



Tropical Waves Initialized at 12 UTC:
TYP SOF INIT 02/00 02/12 03/00 03/12 04/00 04/12 05/00 05/12
TW 21N  52W 56W 57W 60W  62W 64W 66W  DISS
TW 15N  76W 79W 83W 85W  89W 92W 95W  96W 98W
TW 12N  85W 89W 91W 94W  96W 99W 101W  103W 106W


Rivera-Torees...(WPC)