FXCA20 KWBC 061643

PMDCA 



Tropical Discussion - International Desks

NWS Weather Prediction Center College Park MD

1242 PM EDT Wed May 06 2026



Forecast Bulletin 6 May 2026 at 1641 UTC:



The Bahamas and Caribbean:



Relatively stable conditions are expected for The Bahamas and the

Caribbean from today through Saturday. An upper-level high,

reflected at mid-levels and currently situated over the Gulf and

the western Caribbean, will limit the development of deep

convection across the islands through the end of the forecast

period. Additionally, a mid-level ridge over the Caribbean is

anticipated to limit rainfall over the eastern Caribbean today.

While the mid-level ridge will dissipate early on Thursday,

ridging associated with the high over the western Caribbean will

extend, maintaining stability in the region. Some showers can be

expected daily due to diurnal heating, moisture advection and

local effects, but totals will remain low due to the synoptic

conditions and limited precipitable water availability across the

region.



Mexico and Central America:



Over Mexico, light precipitation is anticipated through Thursday

morning, mainly over the Sierra Madre Oriental, with the presence

of a low-level trough increasing moisture advection A more active

rainfall pattern is forecast for northeastern Mexico and the

Sierra Madre Oriental from Thursday through Friday. The main

driver of rainfall will be a frontal boundary that will extend

into northwestern Mexico, increasing moisture, generating

low-level troughs and enhancing low-level moisture convergence.

The heaviest precipitation is expected over the Nuevo Leon region,

with totals ranging from 20-45mm, although higher localized

accumulations are likely.

An approaching mid-to-upper level trough will increase upper-level

divergence, supporting thunderstorms and convective activity.

Instability will continue from Friday through Saturday along the

Sierra Madre Oriental.



Across Central America, light precipitation is expected over the

Pacific coast of Guatemala and El Salvador throughout the forecast

period, with a series of low-level troughs advecting moisture from

the Pacific in the region. Accumulations are expected to range

between 15-20mm. Daily rainfall is also expected over Costa Rica

and Panama, driven by moisture advection from the Caribbean and

enhanced low-level convergence.



Tropical South America:



Heavy precipitation and thunderstorms are expected across the

region daily. The main drivers of precipitation will be diurnal

heating, low-level troughs, moisture advection, orographic lifting

and low-level winds convergence. Daily rainfall is likely over the

Pacific coast of Ecuador and Colombia throughout the forecast

period due to moisture being advected from the Pacific. With

relatively weak winds at low-levels , accumulations should remain

on the lower through Thursday. However, an increase in

accumulations is likely from Thursday through Friday, as low-level

flow shifts perpendicular to the coast. By Saturday, the low-level

winds along the coast will become weaker and disorganized, and

accumulations are expected to decrease.



Over the western Amazon, heavy precipitation is anticipated today

through Thursday with enhanced low-level convergence in the

region, and support for the development of deep convection and

thunderstorms due to upper-level divergence along the Bolivian

High. Less support from upper-levels is forecasted towards the end

of the forecast period, as the Bolivian High becomes less

organized. Higher accumulations of rainfall will happen over the

eastern Amazon and the Guianas from Thursday through Friday,

mainly due to an enhancement in the convergence of winds at lower

levels along the ITCZ and the advection of moisture from the

Atlantic. Totals will range between 35-70mm. From Friday through

Saturday a drying tendency will limit precipitation over most of

the region, although rainfall and thunderstorms will persist due

to local effects and diurnal heating.



Rivera-Torres...(WPC)



$$