FXCA20 KWBC 041911

PMDCA 



Tropical Discussion - International Desks

NWS Weather Prediction Center College Park MD

310 PM EDT Tue Aug 04 2026



Forecast Bulletin 4 August 2026 at 1910 UTC:



(Correction)



Over the next three days, significant rainfall accumulation is

forecast for portions of the Colombian Pacific coast and central

Colombia to southern Nicaragua, with daily maxima of 25 - 50 mm.

Significant rainfall is also expected across portions of Cuba,

Mexico, and Guatemala, with daily maxima ranging between 20 - 45

mm.



In the upper levels, two low-pressure systems, one south of the

Baja California Peninsula and the other over southern Mexico, will

provide favorable conditions for ascent. Another low-pressure

system, currently centered over northern Hispaniola, will track

across the Greater Antilles. Over the next three days, a ridge of

high pressure will strengthen over northeastern Mexico as the

western low continues to move northwestward. The southern low will

shift slightly westward, reducing its influence over western

Mexico. The Caribbean low-pressure system will move westward north

of the Caribbean Sea, favoring dynamical forcing across the region

from The Bahamas to Nicaragua and Colombia. In the mid-levels, a

well-defined trough remains over the southern Baja California

Peninsula with an associated low-pressure anomaly. A noticeable

low-pressure anomaly also persists over the Caribbean basin,

particularly over Colombia and Panama. Over the next three days,

high-pressure anomalies will dominate the region, driven by

strengthening centers over Bermuda and the southwestern U.S.



In the lower levels, elevated precipitable water (PWAT) values are

expected along Mexico's western and southeastern coasts, driven by

humidity advection. PWAT anomalies will remain modest, except over

the northern Sierra Madre Oriental, where values are expected to

exceed two standard deviations above normal. Nonetheless, the

highest rainfall accumulations are anticipated along the western

coast and southern portions of Mexico extending into northern

Central America. A southeasterly moisture flux will support

rainfall over Cuba and The Bahamas over the next three days, while

a plume of Saharan dust limits precipitation over Jamaica,

Hispaniola, Puerto Rico, and the Lesser Antilles. Across southern

Central America and western Colombia, the interaction between the

monsoon trough, regional dynamics, and a passing tropical wave

will sustain significant daily rainfall. The primary area of

precipitation will shift westward from Colombia to Costa Rica and

eastern Nicaragua as the tropical wave propagates. Elsewhere in

northern South America, precipitation will be supported by

low-level moisture advection and orographic lifting over the

Orinoquia and northwest Amazon regions.



Tropical Waves Initialized at 12 UTC:

Typ SOF INIT 05/00 05/12 06/00 06/12 07/00 07/12 08/00 08/12

TW 14N  21W  24W  27W  30W  34W  38W  42W  46W  51W

TW 24N  37W  40W  43W  46W  49W  52W  56W  60W  64W

EW 13N  42W  46W  50W  53W  57W  61W  65W  69W  72W

TW 26N  56W  60W  64W  68W  73W  77W  80W  83W  85W

TW 18N  74W  77W  80W  83W  86W  88W  90W  92W  96W

TW 20N  98W  101W  105W  108W  111W  115W  EXIT  ---







Sanchez-Perez...(WPC)





$$