Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
255 PM EDT Thu Apr 16 2026

Forecast Bulletin 16 April 2026 at 1900 UTC:

In the upper levels...

An upper level trough is currently entering the continental United
States and will influence the propagation of two distinct upper
level features in the Caribbean. Starting Saturday morning, the
trough axis will be located across the United States central
plains and will also interact with another upper level trough that
is embedded within the subtropical jet stream. As these features
interact, they will displace a pre-existing ridge that is
currently situated across southern Mexico and north Central
America. This ridge will start to extend into the interior of the
Caribbean Sea on Saturday and is expected to weaken by the end of
the weekend. Another upper level trough is currently extending
from the Greater Antilles and into the Caribbean Sea and it will
continue to influence the upper level patterns in the region for
the next three days. On Thursday and Friday, the upper trough will
be promoting speed divergence across Colombia and Venezuela.
Starting on Saturday, the trough will tighten and will propagate
eastward as it becomes displaced by the aforementioned upper
ridge.

In the mid to low levels...

Across Hispaniola, Puerto Rico, and the Virgin Islands (VI), the
presence of the upper level is supporting the moistening of the
environment and precipitable water values will be reaching 45mm
for Thursday and Friday. As the upper trough axis shifts eastward
on Saturday, expect drier conditions to return. Meanwhile, a
trough is expected to move out of Hispaniola by Thursday afternoon
and easterly and southeasterly winds will dominate thereafter. On
Friday and Saturday, localized surface-to-low level wind
confluence is expected in Hispaniola, Puerto Rico, and the VI.
With respect to precipitation, moderate total precipitation maxima
will occur in the aforementioned regions for Thursday and Friday
and decreasing for Saturday.

Along the northwest region of South America and Panama, the
increase in northerly low level winds across Panama and into the
Gulf of Panama will assist in the transport of dry air from the
Caribbean Sea into Colombia. On Thursday, a moist plume will be
arriving into the Lago de Maracaibo region and north-central
Colombia, helping keep the environment moist through Friday. The
upper level dynamics will support an increase in instability in
these regions and upper divergence. Thus, enhanced total
precipitation maxima is likely on Thursday. By Friday, moderate
total precipitation maxima is likely.

Starting on Saturday afternoon, a cold front will be moving into
northwest Mexico. As the cold front approaches, there will be an
increase in low level southerly winds across the Gulf and into the
southern plains of the United States. Starting Saturday, low level
winds will shift from the east and will support moisture pooling
across Tamaulipas and Nuevo Leon. Jet dynamics will also be
present in this region. Thus, moderate total precipitation maxima
and a risk for severe weather is likely across Nuevo Leon and
Tamaulipas on Saturday.

 Elsewhere in tropical South Americaâ€
A diffluent upper level pattern will be present across the west
Amazon Basin, favoring upper divergence for the next three days.
There will be a series of low level troughs and regions of low
level wind confluence that will enhance moisture convergence and
vertical ascent. Starting Saturday, expect a drying trend across
the northern half of the west and central Amazon Basin, which will
lead to lower total precipitation maxima. Across the Guianas and
the Amazon Delta, expect elevated precipitable water values for
the next three days. Daily showers and convection are expected in
the region.


Tinoco-Morales...(WPC)