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 Atlantic Basin Tropical Discussion Atlantic | East Pacific 
 
AXNT20 KNHC 111745
TWDAT 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
145 PM EDT Tue Aug 11 2020

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through 
1730 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A broad 1010 mb low pressure centered 
near 12N39W along a tropical wave. Scattered moderate convection 
is noted from 06N-15N between 39W-45W. Environmental conditions 
are expected to be conducive for development to occur, and a 
tropical depression is likely to form during the next day or so 
while the disturbance moves westward to west-northwestward at 
around 10-15 kt across the tropical Atlantic. This system has a 
high chance of tropical cyclone formation during the next 48 
hours. Please see the latest North Atlantic Tropical Weather 
Outlook for more information. A gale warning has been issued 
over the Atlantic high seas, as this system is expected to 
develop gale-force winds in its N semicircle within the next 30 
hours as seas build to 8-11 ft. Note that a tropical storm 
warning will replace the gale warning if/when this system 
becomes a tropical depression. Please refer to the latest High 
Seas Forecast product found at 
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml.

...TROPICAL WAVES...

An eastern Atlantic tropical wave axis is along 24N from 04N-
18N, moving W at 10-15 kt. Scattered moderate convection is 
noted from 09N-14N between 17W-27W. 

A central Atlantic tropical wave axis is along 57W from 02N-22N, 
moving W at 10-15 kt. This wave is well depicted in satellite 
imagery, despite the lack of significant convection. At this 
time, scattered showers are noted over the northern portion of 
the wave.

A west-central Caribbean tropical wave axis is along 75W south 
of 20N, moving W at about 10 kt. Scattered showers are noted in 
the vicinity of the wave. 

...MONSOON TROUGH/ITCZ... 

The monsoon trough extends from the coast of Africa near 21N17W 
to 12N26W to the Special Features low near 12N39W. The ITCZ 
extends west of the tropical wave near 10N42W to 10N54W. Aside 
from the convection related to the tropical waves described 
above, scattered showers are noted along the monsoon trough 
mainly east of 30W.

GULF OF MEXICO...

Surface ridging prevails across the basin, anchored by a 1017 mb 
high centered near 27N87W. Light to gentle winds persist across 
the waters N of 25N, while moderate winds are noted offshore of 
the Yucatan peninsula in the Bay of Campeche.

High pressure will maintain a ridge across the northern waters 
this week, resulting in gentle to moderate winds with slight 
seas across the area. Fresh to locally strong winds are expected 
each evening for the next several nights in the eastern Bay of 
Campeche near the Yucatan peninsula due to local effects. 

CARIBBEAN SEA...

Refer to the section above for details on the tropical wave 
moving across the basin.

Recent GOES-16 satellite imagery show scattered moderate 
convection over the southwest Caribbean, related to the 
extension of the EPAC's monsoon trough. Fresh to strong trade 
winds persist in the south-central waters near the coast of 
Colombia and in the Gulf of Venezuela. Elsewhere, gentle to 
moderate winds prevail.

Fresh to strong trade winds will prevail across the
south-central Caribbean waters through Fri night, with near
gale-force winds expected to pulse near the coast of Colombia
and in the Gulf of Venezuela for the next couple nights. Fresh
winds will pulse for the next several nights through the
Windward Passage. Winds and seas will increase over the Tropical
N Atlantic waters tonight and Wed as a tropical wave crosses the
region. A low pressure system, possibly a tropical cyclone,
could increase winds and seas over the waters E of the Leeward
Islands Fri through Sat as it moves W-NW across the tropical
Atlantic waters. 

A tropical wave approaching the eastern extent of an active phase
of the Madden-Julian Oscillation (MJO) later this week will 
support enhanced moist low-level convergence and the potential 
for heavy rainfall across the SW Caribbean. This could result in 
localized flooding over Central America and northwest South 
America.

ATLANTIC OCEAN...

Please see the sections above for more details on a gale warning 
for the Atlantic high seas and the tropical waves moving across 
the basin.

A surface trough lingers offshore of the NW Bahamas, with 
scattered showers noted west of 69W. Overall, the pressure 
pattern remains weak across the subtropical Atlantic, with light 
to gentle winds over the waters N of 25N. Moderate to locally 
fresh trades prevail across the central tropical Atlantic, south 
of 1024 mb high pressure near 32N42W. Earlier altimeter data 
indicated seas were 6-8 ft in this region. Farther east, fresh 
northerly winds are noted from the Canary Islands southward to 
20N off the coast of Africa.

The trough well offshore of the NW Bahamas will dissipate later 
today. Fresh winds will pulse each night near the coast of 
Hispaniola and over the approach to the Windward Passage. Winds 
and seas will increase E of 65W tonight and Wed as a tropical 
wave crosses the region. A low pressure system, possibly a 
tropical cyclone, could increase winds and seas E of 65W Fri 
night through Sat night as it moves W-NW across the tropical 
Atlantic waters. 

$$

ERA


 
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