Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 220520

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
120 AM EDT Sun Jul 22 2018

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 0000 UTC surface analysis and satellite imagery through 
0515 UTC.


A tropical wave is moving off the coast of Africa accompanied by
thunderstorms. The wave's axis extends along 17N between 10N- 

A tropical wave is in the east-central Atlantic with axis 
extending from 08N-22N along 38W, moving W at 15-20 kt. Saharan 
dry air and dust continue to prevail in the wave's environment as 
shown by CIRA LPW and GOES-16 RGB imagery. This is inhibiting 
large scale convection at this time.

A tropical wave is in the central Atlantic with axis extending 
from 09N-23N along 50W, moving W at 10-15 kt. The wave is moving 
across an extensive area of Saharan dry air, which is hindering 
convection at the time.

A low amplitude tropical wave is moving across eastern Colombia 
with axis extending from 00N-11N along 73W, moving W at 15-20 kt.
Scattered moderate convection is observed across along the wave
axis and between 69W-76W. The wave will lose some definition as 
it moves across the area today, but may emerge into the eastern 
Pacific off Colombia Mon.

A tropical wave is in the west Caribbean and reaching the EPAC
waters with axis from 21N85W to 05N86W. The tropical wave is 
interacting with trade convergence to support scattered showers
over Central America between 85W-93W. 


The monsoon trough axis extends from the coast of Africa near 
18N16W and continues to 08N30W. The ITCZ begins near 07N40W and 
continues to 06N55W. No significant convection is observed at 
this time with these features.



A surface ridge extends across the basin, anchored by a 1017 mb 
high centered near 24N87W. To the west, surface trough extends 
across the Bay of Campeche from 22N30W to 19N93W with scattered 
showers. A shortwave trough at mid/upper levels is supporting 
cloudiness and a few showers over the far east Gulf waters and 
Florida Peninsula. A pre-frontal trough extends across the
Florida from 29N80W to 28N83W. Scatterometer data depicts light 
to gentle anticyclonic winds over most of the basin except north 
of 26N and east of 89W.

The weak trough across Central Florida will gradually settle 
southward over the next few days, bringing moderate west- 
southwesterly flow. The increasing westerly fetch will bring 
gradually higher seas in the offshore Gulf waters by early next 
week. Showers and thunderstorms will persist over the eastern Gulf
today. A surface trough will move off the Yucatan Peninsula into 
the Bay of Campeche each evening, accompanied by fresh nocturnal 
winds and scattered showers.


A tropical wave is moving across the west Caribbean. Refer to the
section above for details. A recent scatterometer pass depicted 
fresh to strong trade winds over the central Caribbean, reaching 
as far north as 17N between 73W-79W. Seas are estimated to be 07 
to 11 ft in this area. Aside from the thunderstorms over the 
southwest Caribbean due to the monsoon trough over 10N, little to 
no shower or thunderstorm activity is noted due to the presence of
Saharan dust and dry air, mainly impacting the eastern Caribbean.

For the forecast, high pressure north of the area will continue to 
support fresh to strong winds in the south-central Caribbean 
through tonight before winds diminish.


Mid to upper-level diffluent flow between a ridge in the west
Atlantic and a trough along the eastern U.S. continue to support 
scattered showers over the west Atlantic mainly west of 70W. To
the east, an upper-level low is reflected at the surface as a
trough that extends from 31N55W to 23N56W. Two tropical waves
extend across the basin. Refer to the section above for details. 
A broad high pressure prevails across the remainder of the basin 
centered near 40N43W. 

For the forecast, high pressure ridge across the northern waters 
will remain in place through the weekend before lifting N Mon 
through Wed. Scattered showers and thunderstorms will persist N of
27N and E of 78W through early next week. Fair weather is 
elsewhere across the Atlantic, however hazy conditions are 
expected S of 26N as the extensive Saharan Air Layer outbreak 
moves across the Atlantic tropical waters.

For additional information 
please visit http://www.hurricanes.gov/marine



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Page last modified: Sunday, 22-Jul-2018 05:20:22 UTC