AXNT20 KNHC 241809
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sat Jul 24 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 1200 UTC surface analysis and satellite imagery through
A 1013 mb low pressure is centered over the waters east of
Daytona Beach, Florida near 29.2N77.4W. This low continues to
produce scattered showers and thunderstorms from the NW Bahamas
northeastward to beyond 31N72W. Strong thunderstorms are capable
of producing locally fresh to strong winds and seas up to 6 ft.
As environmental conditions gradually become more favorable, this
system should slowly develop and there is a medium or 60% chance
a tropical depression could form later this weekend or early next
week. This system is expected to approach the Florida peninsula
late this weekend or early next week, residents in both Florida
and the Bahamas should monitor the progress of this system
closely. Please read the latest Tropical Weather Outlook at
hurricanes.gov, for more information.
Heavy Rainfall in Southern Central America, including Panama,
Costa Rica and Southern Nicaragua. High moisture content,
persistent monsoon flow, and favorable conditions aloft will
continue to support scattered to numerous strong convection
capable of producing torrential rain through early next week. The
heaviest rainfall has been over central Panama, E Costa Rica and
S Nicaragua. These rainfall could cause significant flooding and
mudslides in some areas.
A Caribbean tropical wave is near 66W from N of Puerto Rico at 22N
southward and moving W near 20 kt. Latest VIS and scatterometer
satellite imagery reveals residual Saharan Dry Air and a trade-
wind wind surge accompanying this wave. Enhanced by divergent
winds aloft, scattered showers and a few thunderstorms are
occurring across the Dominican Republic, Puerto Rico and the
Leeward Islands between 56W and 70W. Scattered to numerous
showers and thunderstorms are seen farther N from 19N to 12N
between 61W and 66W.
Another Caribbean tropical wave is along 75W, from the eastern
end of Cuba to N Colombia, and moving W near 15 kt. No
significant convection is associated with this wave.
A third Caribbean tropical wave is near 82W from western Cuba
southward to Honduras and N Nicaragua, and moving W near 5 kt. No
significant convection is associated with this wave.
A monsoon trough enters the Atlantic Ocean at Guinea-Bissau coast
near 12N16W through 09N30W to 09N40W. The ITCZ then continues
from 09N40W to 08N55W, N of French Guiana. Scattered moderate
convection is noted near the monsoon trough from 06N to 10N
between the African coast and 22W. Scattered moderate to strong
convection is found near the ITCZ N of French Guiana and
Suriname, and near the French Guiana coast. Refer to the Special
Features section above for convection related to the monsoon
trough over S central America.
...GULF OF MEXICO...
A surface trough curves westward from a 1013 mb low E of Florida,
mentioned in the Special Features section above; across central
Florida to the N Gulf just E of New Orleans near 29N88W. Scattered
showers and thunderstorms are present SE of New Orleans from 26N
to 29N between 86W and 89W. Locally fresh winds and seas up to 5
ft are probable near heavier showers and thunderstorms.
Otherwise, a 1019 mb ridge of high pressure over the central Gulf
at 26N92W will sustain light to gentle winds and seas of 1 to 3
ft for the remainder of the Gulf.
For the forecast, the high pressure will meander and weaken
through Mon as a low pressure currently located about 175 nm east
of Daytona Beach, Florida meanders offshore of the Florida
Peninsula. This system is forecast to move across north-central
Florida Sun night and Mon.
Refer to the Tropical Waves section above for more information on
convection across the Caribbean Basin.
Increased pressure gradient between the Atlantic ridge and the
monsoon trough over S central America is generating moderate to
fresh winds and seas of 6 to 8 ft across SW and S central basin.
Gentle trades and seas of 2 to 4 ft are evident along the W edge
of the basin, near the Yucatan Peninsula. Gentle to moderate
trades and seas of 3 to 6 ft prevail for the rest of the basin.
For the forecast, the Atlantic ridge N of the Caribbean Sea will
weaken through early next week as the high shifts slowly NE and a
low pressure system persists offshore E of the Florida coast.
This will lead to a gradual diminishing in the strength of the
trade winds across the basin through tonight that will persist
through early Wed. Look for scattered squalls and tstms across the
NE Caribbean today and tonight associated with a fast moving
An upper-level low E of the SE Bahamas at 22N69W is generating
scattered showers and thunderstorms from 22N to 25N between 66W
and 70W. A Refer to the Tropical Waves and Monsoon Trough/ITCZ
sections above for additional convection across the Atlantic
Basin. Also, please see the Special Features section for more
information on the area of low pressure E of Florida.
A persistent surface ridge associated with a 1038 mb high over the
N central Atlantic extends east-southeastward to S Florida.
Gentle to moderate winds and seas of 3 to 5 ft are seen N of 25N
between 28W and 78W. Moderate to locally fresh trades and seas of
4 to 6 ft are present from 12N to 25N between 44W and the Lesser
Antilles, and near the Carnarias Islands from N of 25N between
the NW African coast and 25W. Fresh to locally strong winds and
seas up to 6 ft are probable N of Puerto Rico and the Leeward
Islands. Gentle winds and seas of 4 to 6 ft prevail across the
rest of the basin.
For the forecast W of 45W, the low pressure system is currently
located about 175 nm east of Daytona Beach, Florida.
Environmental conditions are forecasted to become a bit more
favorable for development, and a tropical depression could form
over the next day or so while the low meanders offshore of the
Florida Peninsula. Scattered squalls and tstms associated with a
fast moving tropical wave with axis along 67W will move across
the SE waters and north of the Greater Antilles through tonight.
Winds and seas could be higher near tstms.