AXNT20 KNHC 251050
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sun Jul 25 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
A 1011 mb low is centered near 29N78.5W, where overnight
scatterometer data showed a broad and well defined cyclonic
circulations, with peak winds to 30 kt within 60 nm across the SE
semicircle. Scattered showers and thunderstorms associated with
the low continue to extend from the central Bahamas north and
northeastward to 29N between 75W and 78W. However, the system
still lacks significant convection activity near its center and
therefore has not met the criteria to be designated a tropical
depression. Environmental conditions are expected to remain
marginally conducive for additional development, and tropical
depression could still form today while the low moves generally
westward at 5-10 knots towards the east coast of Florida.
Interests in Florida should continue to monitor the progress of
this system. This system has a medium chance of development within
48 hours. Please read the latest Tropical Weather Outlook at
hurricanes.gov for more information.
Heavy rainfall is expected to continue in Southern Central
America, particularly in 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 Monday. Heavy rainfall in these areas could cause
significant flooding and mudslides.
An Atlantic tropical wave is near 21W from 19N southward, moving
westward at 10 kt. Scattered showers and isolated thunderstorms are
noted from the coast of Africa from Guinea to Sierra Leone and E
of the wave axis.
An Atlantic tropical wave has been introduced along 56W south of
12N moving west at 15-20 kt. Upper air observations and model
diagnostics show this wave exiting the W coast of Africa on Jul
20. Scattered moderate to strong convection is noted from 06N to
08N between 50W and 56W.
A Caribbean Sea tropical wave is along 72W from 22N southward,
moving W 15-20 kt. This wave continues to interact with an upper-
level low across the extreme SE Bahamas, and is generating
scattered to locally numerous moderate to strong convection from
the NE coast of Puerto Rico to 27N between 64W and 70W. The low
level wind surge and Saharan Air accompanying this wave has moved
NW ahead of the wave and reaches as far north as 29N and as far
west as 74W.
A Caribbean Sea tropical wave is near 80W from 22N southward,
moving W near 15 kt. Convection associated with this wave is
confined to near the monsoon trough, S of 11.5N and is described
The monsoon trough enters the Atlantic Ocean at the Guinea-Bissau
coast near 12N16W to 08.5N27W to 09N37W. The ITCZ continues from
09N37W to 07N55W. Scattered moderate convection is noted south of
the monsoon trough from 03.5N to 08.5N and between 23W-37W.
Scattered moderate to isolated strong convection is near the ITCZ
from 03N to 06N between 41W and 48W.
...GULF OF MEXICO...
A surface trough extends into the eastern Gulf from the Florida
coast near 26N82W to 28.5N87W. Widely scattered moderate
convection is along and within 180 nm south of the trough from
the Florida Keys north to 90W. A cluster of scattered strong
convection is in the north- central Gulf, from 27.5N to 29N
between 90W and 91.5W. At the surface, a 1017 mb high pressure
persists near 27N93W. Gentle to moderate winds are noted across
the basin with locally fresh winds likely near the northwest
Yucatan coast. Seas range between 2 to 4 ft.
The high pressure across the N central Gulf will meander and
weaken through Mon as a low pressure currently located east of
Daytona Beach, Florida moves slowly westward toward the Florida
Peninsula, then westward across north central Florida Sun night
and Mon and into the NE Gulf. Generally tranquil marine conditions
are expected to continue across the basin into early next week.
Refer to the Tropical Waves section above for more information on
convection across the Caribbean Basin.
Numerous strong thunderstorms are noted across the SW Caribbean,
south of 11.5N between extreme SE Nicaragua and Colombia, and is
associated with the Pacific monsoon trough. A surface low is
analyzed near the coast of Panama near 10N80.5W. Scattered
moderate convection is noted across the Greater Antilles which are
moving into adjacent waters. Latest ASCAT winds indicates gentle
to moderate trades across the Caribbean with locally fresh winds N
of Colombia. Seas range 3 to 6 ft.
The Atlantic ridge N of the Caribbean will weaken through early
next week as the anchoring high centered across the central
Atlantic shifts slowly NE and low pressure persists offshore of
the Florida coast. This will lead to diminished tradewinds across
the basin through Wed. Look for scattered showers and tstms across
the E Caribbean and tropical Atlantic waters today associated
with another fast moving tropical wave.
See the Special Features section for more information on the low
east of Florida and the Tropical Waves section for information on
the wave off the African coast.
High pressure of 1026 mb is centered near 38N39W and extends west
southwest to the NW Bahamas. A surface trough is analyzed south
of the high from 20N43W to 30N46W. Scattered showers are in the
vicinity of the trough axis. West of 65W, a stationary front is
north of the low center off of Florida, extending from 32n75W to
the coast of Florida near 29.5N81W. Scattered to locally numerous
convection associated with the wind surge preceding the tropical
wave along 72W is described above and dominates much of the waters
south of 27N between 64W and 71W. Moderate to fresh E to SE winds
are noted across the SW N Atlantic south of 28N between 55W and
the Bahamas, where seas 5 to 9 ft. Elsewhere, light to gentle
winds and seas to 5 ft are noted.
The Atlantic ridge will weaken slightly over the next few days as
the anchoring high shifts slowly NE and low pressure persists
offshore and along the N central coast of Florida. Winds will
remain SE across the waters west of 55W through Mon behind the
tropical wave along 72W. Moderate to fresh E winds will return
late Mon through Tue as a broad trough approaches the region from
In the eastern Atlantic, tranquil conditions prevail under
surface ridging anchored by a 1026 mb high near 38N39W. Moderate
to fresh NE winds are noted with seas 5 to 7 ft.