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Atlantic Tropical Weather Discussion
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AXNT20 KNHC 152327
TWDAT
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0015 UTC Sun Aug 16 2026
Tropical Weather Discussion for North America, Central America
Gulf of America, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.
Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.
...SPECIAL FEATURES...
Caribbean Gale Warning: The pressure gradient remains tighten
between surface ridging over the western Atlantic and relatively
lower pressure in northern South America. This will again favor
increasing winds in the south-central Caribbean, supporting gale-
force northeast to east winds off Colombia this evening and into
early on Sun morning. Expect rough to very rough seas to near 15
ft near and downwind of these winds. Please read the latest HIGH
SEAS FORECAST issued by the National Hurricane Center at website
- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest
NWS Offshore Zone Forecast issued by the National Hurricane
Center at website https://www.nhc.noaa.gov/text/MIAOFFNT3.shtml
for further details.
Heavy Precipitation in South Central America and Colombia: Two
tropical waves will propagate into Central America over the next
several days. The wave will interact with enhanced divergence
aloft and an active monsoon trough. The first tropical wave is
located over eastern Honduras and western Nicaragua, or near 86W.
As this wave continues westward, expect heavy precipitation to
continue in Costa Rica, the Darien region and into Choc-Colombia
on into Sun. On Sun, the second tropical wave will enter the
western Caribbean and strengthen the cyclonic rotation over
Panama and Colombia that will favor an increase in available
moisture into Colombia and moist easterly flow into the eastern
portion of Costa Rica. The heaviest precipitation is expected in
Costa Rica through the rest of today and into early on Sun, while
the heaviest precipitation is expected in southwest Panama, the
Darien Region, and Choc-Colombia Sun into Monday. There is some
uncertainty on how far south the heaviest rainfall could reach,
particularly due to how far south the available moisture and the
westerly flow enters the region. Please refer to the WPC
International Desk and local weather services for more
information.
...TROPICAL WAVES...
A far eastern Atlantic tropical wave has its axis along 28W from
05N to 21N. It is moving westward near 15 kt. Scattered moderate
convection is ahead of the wave to near 33W from 09N to 11W.
A central Atlantic tropical wave has its axis along 43W from
04N to 21N, moving westward at 15 to 20 kt. Isolated showers
and thunderstorms are west of the wave to near 47W and from
09N to 15N.
An eastern Caribbean strong tropical wave is along 66W/67W south
of 21N, moving westward at 15 to 20 kt. An area of numerous
moderate to isolated strong convection is present from 14N to 18N
between 64W and 70W.
A far western Caribbean Sea tropical wave is along 86W south of
22N. It is moving westward at about 15 kt. Numerous moderate to
isolated strong convection is increasing over the southwestern
portion of basin in the wake of the wave, where the eastern
segment of the East Pacific monsoon trough is present. The
convection is of the numerous moderate to isolated strong type
confined to south of 13N from 80W westward to over most of Costa
Rica and Panamas as well as southern Nicaragua.
...MONSOON TROUGH/ITCZ...
The monsoon trough axis enters the Atlantic near 21N17W, and
extends southwestward to 15N21W, and to 12N27W to 13N37W and
southwestward to 08N47W, where it transitions to the ITCZ to
08N53W and to near 09N60W. Convection is discussed in the
Tropical Waves section above. In addition, numerous moderate to
isolated strong convection is just inland the coast of Africa
from 07N to 15N.
...GULF OF AMERICA...
A 1023 mb high is centered over the north-central Gulf near
29N92W. Its related gradient is generally supporting gentle to
moderate winds across the forecast waters. Seas over the
basin are 2 to 4 ft. A trough extends from near 22N94W to
18N94W. Scattered moderate to isolated strong convection is seen
west of the trough to 97W from 20N to 23N. Scattered showers and
thunderstorms are over some sections of the Gulf from 22N to 26N
east of 96W. A westward moving mid to upper-level disturbance is
helping to sustain this activity.
For the forecast, the high pressure center will remain over the
north-central Gulf through Mon, then move toward the
southeastern part of the Gulf by Tue while weakening some. This
pattern will continue to support mostly gentle to moderate east
to southeast winds across the basin, with pulses of fresh winds
occurring north and west of the Yucatan Peninsula and into the
Bay of Campeche each night, as a surface trough migrates from the
Yucatan Peninsula westward across the southwestern Gulf. Slight
to moderate seas are expected through the forecast period.
...CARIBBEAN SEA...
See the Special Features section for information on a Gale Warning
that is in effect for the waters offshore Colombia.
Outside of the gale area, fresh to strong trade winds and
rough seas are over most of the Caribbean south of about
18N. Moderate to locally fresh trades continue over the
remainder of the waters along with seas of 4 to 6 ft.
For the forecast, the combination between high pressure over the
western Atlantic and relatively lower pressures in northern South
America will continue to support fresh to strong winds over most
of the east and central Caribbean this weekend. Peak winds to
minimal gale-force are expected offshore Colombia tonight.
The tropical wave over the western Caribbean near 86W will
continue across some sections of Central America tonight, moving
west into the Pacific on Sun. A strong eastern caribbean
tropical wave, with its axis along 66W/67W will continue to
impact the eastern Caribbean through Sun, with numerous showers
and thunderstorms, some heavy with strong gusty winds. These
weather conditions are forecast to shift westward to the western
Caribbean Sun through Mon night.
...ATLANTIC OCEAN...
High pressure, anchored by a 1024 mb high center south-southwest of
Bermuda near 26N69W continues across the basin. Latest satellite
Ascat scatterometer data indicates fresh northeast winds along the
coast of western Sahara and through the Canary Islands. Seas are
around 6 to 7 ft with these winds. Elsewhere, latest satellite
scatterometer data passes reveal moderate or weaker trades.
Seas are about 4 to 6 ft with these trades.
Scattered moderate convection is seen from 29N to 30N between
66W and 71W, and from 30N to 31N between 61W and 66W. The base
of a broad upper-level trough translating eastward is north of
31N between 50W and 70W, with impulses riding along it from west
to east. This activity is also south of a stationary front that
is well north of the area.
Of note: An extensive plume of Saharan Air Layer (SAL) is
spreading westward across most of the basin south of about 28N
and just east of South Florida and the Keys as noted in the GOES-
derived Total Precipitable Water (TPW) product. From climatology,
the SAL usually becomes evident around the middle of June, peaking
from late June to mid-August, then begins to rapidly diminish after
mid-August.
For the forecast west of 55W, the Bermuda-Azores High, combined
with the passage of two tropical through the Caribbean Sea will
cause fresh to strong NE to E winds south of 22N including the
approaches and in the Windward Passage from late this afternoon
through Sun night. Looking ahead, a cold front will slowly push
across the northern forecast border east of 70W late on Sun, and
move across the northern forecast waters on Mon while dissipating
into a trough by Tue. Fresh to strong southwest to west winds
are expected ahead of the front and east of about 70W on Sun and
Sun night.
$$
Aguirre
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