971
FXCA20 KWBC 281936
PMDCA

Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
336 PM EDT Tue Jul 28 2026

Forecast Bulletin 28 July 2026 at 1930 UTC:

Over the next three days, the most significant shower activity is
expected across portions of northern Central America, particularly
Nicaragua and Honduras, along with southern and western Mexico,
where maximum totals of 50 to 75 mm are possible, with locally
higher amounts in isolated spots. Similar totals are possible
across portions of tropical South America and Panama. Most of the
Caribbean and the Bahamas, however, are expected to see only
modest rainfall over the next several days as drier air moves into
the region.

In the upper levels, a high pressure system is dominating most of
the region, extending from the Gulf all the way down into the
Bahamas. There is also an upper level low north of Puerto Rico in
the western tropical Atlantic, along with another low pressure
system over the central Caribbean just southwest of Jamaica. Over
the next three days, the low southwest of Jamaica is expected to
move west into southern Mexico, while the upper low north of
Puerto Rico elongates and shifts southward into the east central
Caribbean by Thursday night. The mid levels are not quite as
complex, with a high pressure system extending into the Gulf as
well, and a slight inverted trough present in the western
Caribbean, along with additional troughiness across the central
Caribbean and into areas north of Hispaniola. This pattern is
expected to evolve such that by Thursday night, a strong mid-level
high pressure system builds over the northern Caribbean and
dominates the area, leaving only a weak inverted trough over the
southern Gulf and into Mexico, with southerly flow otherwise
persisting across the Caribbean.

At the low levels, a strong high pressure system across the
central Atlantic will dominate the pattern over the next several
days. The Caribbean low level jet is developing in response, aided
by an additional strong high pressure system over the Gulf. There
is no major troughiness expected outside of the tropical waves
that will move through the area by Thursday night and into Friday.
By Friday, the high pressure over the central Atlantic strengthens
further, driving an even stronger Caribbean low level jet, and
this high extends all the way into the Gulf, supporting
significant easterly and southeasterly winds across the region.

An Atlantic high pressure system, with an associated ridge
extending toward the ABC Islands, will continue to strengthen and
gradually shift westward over the next several days. As the
pressure gradient across the eastern and central Caribbean
increases Wednesday and Thursday, trade winds are expected to
strengthen progressively, reaching fresh to strong levels, with
the strongest winds anticipated across the Windward Islands, the
ABC Islands, and along the northern coasts of Venezuela and
Colombia. As this high pressure system continues its westward
progression at the low and mid levels, the low-to mid-level
subsidence inversion across the Caribbean basin is expected to
strengthen further, promoting stable conditions and inhibiting the
development of deep convection. Although tropical waves will
continue to traverse the Caribbean, the prevailing dry and stable
environment will significantly limit convective activity, and any
associated precipitation is expected to be light and isolated,
with most areas receiving only trace amounts of rainfall.

It is also worth mentioning that drier air and Saharan dust will
be moving into the region. Some Saharan dust is already present
across the eastern Caribbean and the Atlantic, and by Thursday and
into Friday, this plume will move into the central Caribbean,
keeping conditions relatively dry with mostly isolated convection
given the density of the dust. Overall, near to below normal
moisture is expected across the area, with the exception of areas
tied to the tropical waves currently moving through the region.
Across the southern Caribbean and into Nicaragua, there is higher
than normal moisture in place, with precipitable water values
nearing 50 to 55 mm, or around 125 percent of normal. A second
plume of moisture is present across the eastern Caribbean, tied to
another tropical wave, also with precipitable water values between
50 and 55 mm, and this plume is expected to continue moving
westward with the trade winds through the weekend.


SOF  INIT  29/00  29/12  30/00  30/12  31/00  31/12  01/00  01/12
14N  36W   39W    42W    46W    48W    51W    54W    55W    56W
19N  62W   65W    658    72W    76W    78W    82W    85W    88W
15N  81W   83W    86W    88W    92W    94W    96W    98W   100W
11N  89W   92W    95W    97W    98W   101W   104W   107W   109W
15N 102W  105W  106W  107W  108W  110W  112W   114W   116W



Alamo...(WPC)


$$