Tropical Weather Discussion
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000
AXNT20 KNHC 291000
TWDAT

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.

...SPECIAL FEATURES...

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
listed on the website: WWW.METEOFRANCE.COM/PREVISIONS- METEO-
MARINE/BULLETIN/GRANDLARGE/METAREA2.

...TROPICAL WAVES...

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.

...ITCZ/MONSOON TROUGH...

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
time.

...DISCUSSION...

...GULF OF MEXICO...

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.

...CARIBBEAN SEA...

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.

...HISPANIOLA...

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.

...ATLANTIC OCEAN...

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.

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

$$

ERA




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