Tropical Weather Discussion
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AXNT20 KNHC 201032

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
632 AM EDT Thu Jul 20 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 is over the far eastern Atlc with its axis
extending from near 18N25W to 04N26W, moving W at 20 kt. SSMI
imagery shows a moist area from 05N-17N between 13W-27W. There is
also a well defined 700 mb trough associated with the wave.
Saharan dry air and dust is NW of the wave environment. Scattered
moderate to isolated strong convection is from 10N-14N between

A tropical wave with an embedded low pressure is in the central
Atlantic. The axis extends from 18N49W to a 1012 mb low near
12N49W to 08N49W, moving W at 15 kt. The SSMI total precipitable
water imagery shows a very large moist area over from 02N-24N
between 40W-53W. The embedded surface low is well defined.
Saharan dry air and dust is NW of the wave environment. Potential
for tropical cyclone development from this system remains low
through the next two days. Scattered moderate convection is from
13N-16N between 48W-51W.

A tropical wave is approaching the Lesser Antilles. The axis
extends from 20N56W to 08N57W, moving W at 20 kt. SSMI
imagery shows only a slightly moist area from 10N-20N. There is
a well defined 700 mb trough, however, associated with this wave.
Scattered showers are W of the wave axis over the Lesser Antilles
from 13N-19N between 58W-62W.

A tropical wave is over the central Caribbean Sea, the remnants
of former Tropical Storm Don. The wave axis extends from 19N72W
to 08N72W, moving W at 20 kt. The wave is in an unfavorable wind
shear environment. However, abundant low to mid level moisture
is S of 17N. Scattered moderate to isolated strong convection is
over W Venezuela and N Colombia from 06N-10N between 71W-75W.

A tropical wave is in the W Caribbean with axis extending from
22N82W to Costa Rica near 07N84W, moving W at 20 kt. SSMI TPW
imagery depict abundant moisture associated with this wave. The
wave is however, in a region of unfavorable wind shear, and
Saharan dry air and dust are affecting the western periphery of
the wave environment. Scattered moderate convection is along the
coast of Nicaragua from 10N-15N between 82W-85W.


The monsoon trough axis extends from 15N17W to 09N32W. The ITCZ
then extends from 09N32W to 06N39W to 10N46W. The ITCZ resumes W
of a tropical wave near 10N50W and extends to the coast of South
America near 09N61W. Aside from the convection associated with
the tropical waves, scattered moderate convection is from 06N-12N
between 30W-40W.



A surface trough is over the Yucatan Peninsula from 21N88W to
16N94W. Scattered showers are within 60 nm of the trough axis.
A 1019 mb high is centered over the NE Gulf of Mexico near
27N87W. 5 kt anticyclonic winds are noted around the high. The NW
Gulf has 5-10 kt SW flow. Radar imagery shows isolated showers
over the Straits of Florida, and Florida. In the upper levels, an
upper level low is centered over Mexico near 24N100W enhancing
convection over Mexico. Another upper level low is centered off
the coast of Georgia near 31N79W. Expect in 24 hours for the
latter upper level low to move to NE Florida. Also expect this
upper level low to also move to the NE Gulf of Mexico in 48
hours, with convection. In addition, expect scattered showers and
thunderstorms to form over the Bay of Campeche, during maximum
heating today.


The main features in the basin are two tropical waves. The pacific
monsoon trough also extends to N Colombia, producing scattered
moderate convection over the SW Caribbean S of 11N. In addition,
isolated moderate convection is over the NW Caribbean from 19N-
22N between 80W-88W.


A fast moving tropical wave is moving S of the island. Mostly fair
weather is now present. Expect mostly fair weather for the next 24


Scattered showers are over the N Bahamas and the W Atlantic, N of
25N and W of 73W. A large 1023 mb high is centered over the
central Atlantic near 31N59W. Of note in the upper levels, two
upper level lows are over the W Atlantic at 31N79W and 26N69W
enhancing showers. Another upper level low is also centered over
the central Atlantic near 30N49W enhancing showers W of center.

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