Tropical Weather Discussion
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AXNT20 KNHC 140531

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
131 AM EDT Mon Aug 14 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 0000 UTC surface analysis and satellite imagery through
0530 UTC.


Tropical Storm Gert is centered near 28.9N 71.9W at 14/0300 UTC,
moving toward the north-northwest, or 345 degrees, at 8 kt. The
system is expected to remain east of the United States, taking a
turn toward the north by this morning, followed by a turn toward
the north- northeast tonight. Estimated minimum central pressure
is 1009 mb. Maximum sustained wind speed is 40 kt with gusts to 50
kt. Numerous moderate and scattered strong convection is noted
within 90 nm southeast and 30 nm northwest semicircles of Gert.
Scattered moderate isolated strong convection is noted elsewhere
within 150 nm southeast and 60 nm northwest semicircles of Gert.
See latest NHC forecast/ advisory under AWIPS/WMO headers
MIATCMAT3/WTNT23 KNHC for more details.


The axis of a tropical wave is near 23W from 05N to 21N, with low
pressure centered along the wave axis near 14N23W, moving W at 15
kt. Environmental conditions are expected to become more
conducive for development of this low later this week. and there
is a medium chance for tropical cyclone formation within 5 days.
Scattered showers are noted from 09N to 16N between 20W and 25W.

The axis of a tropical wave is near 37W from 06N to 21N, moving W
at 20 kt. This wave is very evident in low-mid level satellite
cloud wind vectors. Scattered showers are within 90 nm of the
wave axis south of 13N.

The axis of a tropical wave is near 55W from 07N to 21N, moving W
at 15-20 kt. There is limited convection associated with this
wave, with isolated showers noted near the southern end of the
wave axis, from 08N- 11N between 53W- 56W.

The axis of a tropical wave in the far western Caribbean is near
88W from 08N to 21N, moving W at 15 kt. This wave is helping
produce active convection over the western Caribbean as well as
the Yucatan Peninsula, Belize, Guatemala, Honduras, and


The monsoon trough extends from the coast of Africa near 14N17W
to 14N24W to 10N38W to 10N47W. The Intertropical Convergence Zone
continues from 10N47W to 10N52W. It resumes from 10N56W to the
coast of South America near 09N61W. Aside from the convection
associated with the tropical waves, scattered moderate isolated
strong convection is noted from 06N-15N between 25W-33W, and from
06N-12N between 40W- 47W.



A ridge of high pressure prevails over the Gulf of Mexico, except
for a thermally induced trough which has moved off the Yucatan
Peninsula into the southwest Gulf. Latest surface observations
indicate with light to gentle anticyclonic flow covering much of
the Gulf waters, with two exceptions. The first is an area of
moderate to fresh winds west of the trough in the southwest Gulf.
The second is over the far western Gulf where moderate to fresh
winds prevail due to a tighter pressure gradient between the ridge
and a trough of low pressure over Mexico. The ridge will remain
across the Gulf waters the next several days with these general
conditions prevailing.

A thermal trough will develop each evening over the Yucatan
Peninsula, shifting westward into the southwest Gulf during the
overnight hours, and dissipating over this area each morning.
Locally higher winds can be expected west of the trough axis.


A tropical wave is moving through the far western Caribbean, and
will move west of the area early this morning. Please see the
tropical wave section above for more information. The western
Atlantic ridge has started to build westward south of T.S. Gert.
This has started to tighten the pressure gradient over the area.
Latest surface observations indicate fresh to strong winds over
the south central Caribbean, moderate to fresh winds over the
north central Caribbean, moderate winds over the eastern
Caribbean, and gentle to moderate winds over the western
Caribbean. The ridge will continue to build as Gert moves further
north. This will bring an increase in coverage of fresh winds
across the north central and eastern Caribbean through midweek.


Earlier convection across Hispaniola has dissipated. Expect
daytime heating, local sea breezes and mountain upslope lifting to
produce scattered showers and thunderstorms during the afternoon
and evening hours across the island the next couple of days.


Please see the Special Features section above for more on
Tropical Storm Gert, and the Tropical Wave section above for more
on the tropical waves propagating across the tropical Atlantic
waters. Outside of these areas, the forecast area is under the
influence of the subtropical high. This high pressure area has
started to build westward into the southwest north Atlantic waters
in the wake of T.S. Gert as the system moves northward. Moderate
to fresh winds prevail over the eastern waters between the two
easternmost tropical waves and the subtropical high, with gentle
to moderate winds elsewhere. The area of fresh winds will spread
westward along with the tropical waves the next couple of days.

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