Tropical Weather Discussion
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AXNT20 KNHC 271031

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Jul 27 2021

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, 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 0600 UTC surface analysis and satellite imagery through
0930 UTC.


A tropical wave is in the E Atlantic south of 20N with axis along
31W/32W, moving W at 10-15 kt. A broad area of Saharan Air
accompanies this wave, which is hindering convection north of 10N at
this time. Associated scattered moderate convection is confined to
near the ITCZ, from 05N to 09N between 28W and 38W.

A tropical wave is in the E Caribbean extending S of 15N along
69W, moving W at 15 kt. A dry and stable low-level dry airmass
immediately follows this wave and is limiting convection to
isolated showers to S of 13W and E of 69W.

A tropical wave is in the central Caribbean extending S of 20N
with axis near 79W, moving W at 10-15 kt. Upper-level divergence
is supporting scattered showers and isolated tstms from Jamaica to
coastal Nicaragua.

An ill defined tropical wave is in the W Caribbean extending from
the Gulf of Honduras south into the eastern Pacific waters along
87W. Scattered moderate to strong convection is across coastal
Nicaragua, and across the Pacific waters N of 11N between 88W and


The monsoon trough extends from the coast of Africa near 12N16W
to 07.5N31W to 08N41W. The ITCZ continues from 08N41W to 09.5N60W.
Scattered moderate isolated strong convection is from 05N to 12N
east of 53W.


A weak pressure gradient across the basin supports light to
gentle variable winds across the gulf with seas in the 1 to 3
ft range. A middle to upper-level low over the western basin
supports scattered to isolated showers over the NE Mexico
adjacent waters. Over the eastern half of the basin, a surface
trough supports similar shower activity on the SE gulf and
Yucatan Peninsula.

Weak high pressure persists across the northern Gulf along 29N
while a trough extends from offshore of Tampa Bay, Florida to
24N91W. Scattered showers and isolated thunderstorms will persist
near and south of the trough axis through tonight as if drifts
westward. Atlantic high pressure will begin to build westward into
the Gulf region Wed and Thu, with a ridge persisting along 27N
through Sat.


Three tropical waves are moving across the Caribbean supporting
some localized shower activity. Aside from showers, two of these
waves are supporting moderate to locally fresh trade winds across
the eastern and central Caribbean with seas to 5 ft. See the
tropical waves section for further details.

Gentle to moderate trade winds are expected through early Wed.
The exception will be moderate to locally fresh winds
near the coast of Colombia, and in the Gulf of Venezuela. Winds will
increase across the E and central Caribbean Wed night through
Fri as the Atlantic ridge builds westward in the wake of a trough
moving westward across the Atlc waters north of the Greater


A surface ridge dominates the subtropical Atlantic waters and
supports and provides mostly fair weather with gentle to moderate
winds, and seas in the 3 to 5 ft range. A surface trough is
analyzed near 24N57W to 17N56W. A small cluster of scattered
showers and thunderstorms are noted in the vicinity of the
trough. Otherwise, diffluent flow aloft supports scattered showers
NE of the Bahamas.

A weak Atlantic ridge extends from SE of Bermuda to near the NW
Bahamas and will change little through tonight. An elongated area
of showers and thunderstorms extending northward of 21N between
62W and 70W will persist north today then begin to diminish
tonight. A broad inverted trough along 57W will move quickly
westward and across the SE waters through tonight then north of
the Greater Antilles and across the southern Bahamas Wed through

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