Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 291000

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
600 AM EDT Thu Jun 29 2017

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 0600 UTC surface analysis and satellite imagery through 
1000 UTC.


Northerly winds will increase to gale-force tonight in AGADIR AND
TARFAYA through 30/0000 UTC. The outlook for the 24 hours that 
follow the forecast that is valid until 01/0000 UTC, consists of 
the threat of severe northerly gale winds over AGADIR and TARFAYA.
Gale-force winds are also expected over eastern MADERIA and 
CANARIAS. Please refer to the METEO- FRANCE High Seas Forecast 


A tropical wave extends just west of the coast of Africa from 
20N19W to 07N14W, moving westward at 10-15 kt. The wave is 
embedded within a rather large envelope of deep moisture as seen 
in the latest satellite animation. Scattered showers and thunderstorms
are observed south of 12N between 15W-20W.

A tropical wave over the central Atlantic has its axis extending 
from 15N41W to near 01N44W, moving westward at about 10-15 kt. 
Satellite imagery and TPW data indicate that moisture around the 
wave due to a large area of Saharan dust that intruded from the 
north towards the wave. Satellite imagery showed elongated 
cyclonic turning of the low clouds around the vicinity of the 
wave. No significant convection is present at this time.

The tropical wave over the eastern Caribbean was repositioned
after analyzing model diagnostics and satellite imagery. Its axis
extends from 18N68W to 10N70W, moving west at about 15 kt. This 
wave is accompanied by scattered moderate convection that extends
across the eastern Caribbean east of 72W. Some of this activity 
may most likely be attendant by strong gusty winds. The wave is 
forecast to continue moving west across the eastern Caribbean 
through Friday. Expect increasing showers and thunderstorms with 
gusty winds to move across these waters.

A tropical wave over Central America with axis along 88W from
08N-18N, moving westward at about 10 kt. The axis of this wave 
continues to mark the leading edge of a surge of deep tropical 
moisture. Isolated moderate convection remains inland affecting 
portions of Honduras and Nicaragua and the EPAC. Some of this 
convection may contain locally heavy rainfall. The shower and 
thunderstorm activity approaching those countries from offshore 
may bring gusty winds and locally heavy rainfall through the 
afternoon hours.


The Monsoon Trough remains inland across Africa. The Intertropical
Convergence Zone then extends from 07N18W to 10N40W, then resumes
west of a tropical wave near 10N45W to 07N58W. Aside from the 
convection related to the tropical wave along the African coast 
discussed above, no significant convection is observed at this 



A mid to upper-level trough is evident on water vapor imagery to 
be just inland the Texas and southwest Louisiana coasts. An
upper-level low has developed over the north-central Gulf
supporting a cluster of moderate convection north of 28N between 
87W-92W. To the east, a stationary boundary extends northward 
from inland Texas and Louisiana to just along the Florida 
panhandle coastline. Isolated showers are expected along the 
frontal boundary. The surface analysis reveals a weak pressure 
pattern present over the remainder of the basin. With little 
changes to the present synoptic pattern forecast through Friday, 
the convection described over the north-central Gulf is expected 
to continue through at least the next 24 hours.


The main feature presently in the basin is a strong tropical wave
that is currently located over the southeastern Caribbean. 
Another tropical wave over Central America. These features are 
discussed in the section above. Aside from the convection related 
to these features, generally fair weather prevails elsewhere. 
Scatterometer data depicts moderate to fresh trades across the 
basin, except in the south-central Caribbean south of 15N between 
72W-76W where a stronger pressure gradient present there is 
supporting strong northeast to east winds. Little change is 
expected with these winds through Friday. The tropical wave 
over the southeastern Caribbean will be the main feature during 
the next 48 hours. Scattered showers and abundant cloudiness are 
noted east of 72W. Convection is expected to continue as the wave 
moves west through the day. The impacts of this wave as related 
to marine interests will be mainly highlighted in the Offshore 
Waters Forecast and High Seas Forecast products. 


Fair weather prevails across the island at this time. Guidance 
suggests that little change is expected in the present weather 
pattern today, then increasing moisture along with scattered 
showers and thunderstorms starting this evening as a strong 
tropical wave approaches from the southeast.


Two tropical waves were analyzed across the basin. Refer to the
section above for details. A stationary front extends across the 
west Atlantic from 32N69W to 29N81W. A pre-frontal trough is 
located from 30N71W to 25N78W. Isolated showers are expected 
along these boundaries. To the east, an upper-level low is 
reflected at the surface as a trough that extends from 30N59W to 
22N62W. Another surface trough extends from 32N37W to 29N37W with
isolated showers. A third surface trough was analyzed across the
east Atlantic extending from 22N29W to 18N26W. The remainder of 
the basin is under the influence of a surface ridge, anchored by a
stationary 1032 mb high centered near 40N31W. The wind flow 
pattern around the southern periphery of this high pressure will 
continue to transport Saharan African dust westward to the the 
central Atlantic through Friday.

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Page last modified: Thursday, 29-Jun-2017 10:00:53 UTC