FXCA20 KWBC 041816

PMDCA 



Tropical Discussion - International Desks

NWS Weather Prediction Center College Park MD

216 PM EDT Mon May 04 2026



Forecast Bulletin 4 May 2026 at 1800 UTC:



The Bahamas and Caribbean:



A frontal boundary extending from the Atlantic into the Gulf is

anticipated to enhance precipitation over the Bahamas and  Cuba,

starting today through Tuesday morning. An eastward-propagating

upper-level trough over the eastern U.S. will also increase

upper-level divergence, particularly over The Bahamas, promoting

the development of thunderstorms and convective activity. A slight

risk for severe weather exists from today through Tuesday morning

for The Bahamas. Remnants of the frontal boundary will continue to

bring light precipitation into the Bahamas and Cuba from Tuesday

through Wednesday. Less precipitation and more stable conditions

are anticipated from Wednesday through Thursday, as an upper-level

ridge, reflected at mid-levels moves from Mexico into the Gulf.



Elsewhere in the Caribbean, light precipitation due to diurnal

heating, and local effects can be anticipated throughout the

forecast period, producing daily accumulations between 05-15mm. As

the upper-level trough, currently affecting the Bahamas,

propagates and reaches the eastern Caribbean some shallow

convection is expected over Hispaniola and Puerto Rico from

Wednesday through Thursday; however, low levels of precipitable

water will limit accumulations of rainfall.



Mexico and Central America:



Over most of Mexico, conditions are expected to remain fairly

stable throughout the forecast period with a ridge dominating at

mid- and upper-levels and low precipitable water prevailing in the

region. Light precipitation can be expected today through Tuesday

over the Yucatan Peninsula, and Belize, southwestern Mexico and

portions of Guatemala, driven by low-level troughs advecting

moisture into the region and enhancing low-level convergence.



Rainfall and convective activity are anticipated every day over

portions of Nicaragua, Costa Rica and Panama with deep moisture

available in the region. The presence of low-level troughs will

further enhance the advection of moisture from the Caribbean into

the region. At mid-levels, the presence of a shortwave trough will

enhance instability over Nicaragua and Costa Rica particularly on

Tuesday. At upper-levels an increase in divergence is anticipated

over Costa Rica, further increasing precipitation from Tuesday

through Wednesday morning.





Tropical South America:



Heavy precipitation and thunderstorms are expected across the

region each day. The main drivers of precipitation will be

low-level convergence, moisture advection, orographic lifting,

diurnal heating and local effects. Today through Tuesday morning

the heaviest precipitation is anticipated over the western and

central Amazon region, as a  low-level trough over Peru enhances

low-level moisture convergence over the region and deep moisture

is advected in the area. Additionally, an enhanced upper-level

divergence is anticipated along the periphery of the Bolivian High

which will persist throughout the forecast period.



 From Tuesday through Wednesday, the presence of the ITCZ and the

Near Equatorial Trough (NET) will bring the heaviest precipitation

to the Amazon Delta, and Eastern Amazon region by increasing

moisture convergence at low-levels. Additionally, the propagation

of a low-level trough will bring precipitation into the Guianas.



Light to moderate precipitation is likely to occur over the

Pacific Coast of Colombia and Ecuador from Tuesday through

Wednesday as a low-level trough promotes the advection of moisture

from the Pacific into the region. The low-level winds, however,

are expected to remain relatively weak limiting high accumulations

of rain. Moisture advection from the Pacific into the coasts of

Colombia and Ecuador will continue from Wednesday through

Thursday, bringing more rainfall to the region.



Moderate precipitation is also expected over the Amazon and

portions of the Orinoquia region in Colombia from Tuesday through

Wednesday due to the presence of a low-level trough and moisture

advection in the region.





Rivera-Torres...(WPC)



$$