Tropical Weather Discussion
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AXNT20 KNHC 221038

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
638 AM EDT Tue Aug 22 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
1015 UTC.


A tropical wave extends from 24N87W to 13N88W moving W-NW at
10-15 kt. The remnant circulation of Harvey continues to be
analyzed as a 1011 mb low pressure along the wave axis near
18N88W. Scattered moderate to isolated strong convection is from
18N-23N between 79W-89W. Satellite images and surface
observations indicates the low is along the coast of N Belize.
Tropical cyclone development is expected when the system moves
over the Bay of Campeche tonight or early Wednesday, and a
tropical depression is likely to form over the southwestern Gulf
of Mexico on Wednesday or Thursday. Regardless of development,
locally heavy rainfall and gusty winds are expected to spread
westward across Belize and the Yucatan peninsula during the next
day or so. There is a high chance for this system to become a
tropical cyclone within 48 hours.


A tropical wave extends from 24N29W to 10N32W moving W at 15-20
kt. A 1011 mb low pressure precedes the wave centered near
12N38W. Scattered moderate convection is from 09N-14N between
25W-33W. This wave in a moist area based on TPW imagery and has a
well pronounced 700 mb trough.

A tropical wave extends from Puerto Rico near 19N67W to Venezuela
near 10N68W, moving W at 20-25 kt. Isolated showers are within 120
nm of the wave axis. Subtle troughing is noted on 700 mb streamline
analysis. Some moisture is observed on either side of the wave
axis based on the SSMI TPW animation. This wave will cross the
central Caribbean through mid-week.


The monsoon trough extends from 18N16W to 18N27W to 12N38W to
07N42W to 07N46W. The Intertropical Convergence Zone axis
continues from 07N46W to 06N58W. Besides the convection mentioned
in the tropical wave section, scattered moderate to isolated
strong convection is along the coast of W Africa from 08N-14N
between 12W-17W. Isolated moderate convection is from 05N-08N
between 35W-43W.



Weak surface ridging is over the Gulf of Mexico with axis along
30N. 10-15 kt easterly surface flow is over the N Gulf. The
northern extent of a tropical wave is producing scattered moderate
to isolated strong convection over the SE Gulf of Mexico, Yucatan
Channel, and the N Yucatan Peninsula. Scattered showers and
isolated thunderstorms are also advecting over S Florida from the
Atlantic. In the upper levels, an upper level low is centered over
the W Gulf near 27N91W enhancing showers. Expect over the next 24
hours for the upper level low to remain quasi-stationary and
continue to produce showers. Looking ahead, the remnant low of
Harvey and tropical wave, will traverse the Yucatan Peninsula
today, and then move into the Bay of Campeche Wednesday, where
redevelopment to a tropical cyclone appears likely.


The remnant low of Harvey currently located over N Belize continues
to be the primary area of concern across the basin. Please, see
Special Features section for more details. A tropical wave is over
the eastern Caribbean. Please, see the Tropical Waves section for
details. Patches of low-level moisture embedded in the trade wind
flow are noted over parts of the east and central Caribbean.
Fresh SE winds are observed per scatterometer data across the
central Caribbean, but mainly N of 13N. These winds are the result
of the pressure gradient between the Atlantic ridge and the
remnant low of Harvey.


Presently, showers are over SW Haiti. However,daytime heating,
local sea breezes and mountain upslope lifting will combined with
available moisture to produce scattered showers and thunderstorms
during the afternoon and evening hours today. The next tropical
wave is forecast to pass just south of the island tonight into


A trough of low pressure continues to move westward across the
Bahamas and now extends from 29N77W across the N Bahamas to
central Cuba near 22N79W. This system continues to produce
disorganized showers and thunderstorms, with fresh to strong winds
mainly on its NW side based on scatterometer data. Only slow
development of this system is anticipated today while it moves
west-northwestward towards Florida. Farther east, there is
another surface trough that extends 24N55W to 16N55W. Scattered
moderate convection is from 23N-25N between 51W-54W. An upper-
level low is also centered near 27N59W. A 1022 mb high is centered
W of Bermuda near 32N72W. Another 1022 mb high is centered over
the central Atlantic near 32N48W. The tail end of a cold front is
over the E Atlantic from 31N32W to 28N40W. Scattered showers are
within 90 nm of the front.

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