Tropical Weather Discussion
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AXNT20 KNHC 191033

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
633 AM EDT Wed Jul 19 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 off the coast of W Africa with axis from
15N19W to 06N20W moving W at 20kt. SSMI imagery shows a moist
area from 04N-15N between 12W-24W. There is also a well defined
700 mb trough associated with the wave. Widely scattered moderate
convection is from 07N-13N between 15W-26W.

A tropical wave with an embedded low pressure is in the central
Atlantic. The axis extends from 18N41W to a 1011 mb low near
12N41W to 04N42W, moving W at 5-10 kt. The SSMI total
precipitable water imagery shows a very large moist area over from
02N-24N between 33W-46W. The embedded surface low is well
defined. Widely scattered moderate convection is from 09N-16N
between 39W-46W. Some slow development of this system is possible
during the next day or two while it moves toward the west-
northwest. Potential for tropical cyclone development from this
system remains low through the next two days.

A tropical wave is in the E Caribbean with axis extending from
20N69W to inland Venezuela near 10N70W, moving W at 20 kt. The
wave is in a region of unfavorable wind shear, and Saharan dry air
and dust are affecting the western periphery of the wave
environment. Isolated showers are within 90 nm of the wave axis.


The monsoon trough axis extends from 12N16W to 07N25W to 12N41W
to 09N48W. The ITCZ then extends from 09N48W to 06N56W. Aside
from the convection associated with the tropical waves, widely
scattered moderate convection is from 06N-09N between 23W-26W.



A surface trough is over the Yucatan Peninsula from 20N90W to
16N92W. Scattered showers are within 60 nm of the trough axis.
Further W, scattered moderate to isolated strong convection is
over the W Bay of Campeche and S Mexico from 14N-21N between 93W-
97W. The remainder of the Gulf of Mexico has weak surface ridging
5-10 kt southerly flow. Radar imagery shows scattered showers
over the Straits of Florida, Florida, and the N Gulf N of 25N. In
the upper levels, an upper level low is centered over Mexico near
23N98W. Upper level diffluence SE of the center is enhancing
convection over S Mexico. Expect in 24 hours for a 1019 mb high to
form over the NE Gulf near 28N87W. Also expect scattered showers
and thunderstorms to form over Florida, and the Bay of Campeche,
during maximum heating today.


The main feature of concern for the SE Caribbean is the remnants
of Don moving across the Windward Islands, and a tropical wave
along 69W. Remnants of Don on 19/0900 UTC is centered near the
island of La Blanquilla at 12N64W, moving westward at 22 kt.
Estimated minimum central pressure is 1012 mb. Scattered moderate
convection is over the Windward Islands from 11N-13N between 63W-
68W. The remnants of Don is expected to produce total rain
accumulations of 3 to 6 inches. There remains a potential for
life-threatening flash floods and mudslides, along the coast of
Venezuela. In addition, scattered moderate to strong convection
is inland over SE Venezuela, and over N Colombia. Scattered
moderate to strong convection is over the SW Caribbean S of 11N.
Elsewhere, scattered showers and isolated thunderstorms are over
the NW Caribbean from 16N-21N between 79W-85W. Of note in the
upper levels, an upper level low is centered over E Cuba near
19N75W. Expect additional convection over the S Caribbean and
Central America over the next 24 hours.


A fast moving tropical wave is supporting isolated showers
across the Dominican Republic and adjacent waters. The wave will
traverse the island today. Expect scattered thunderstorms over
the island during maximum heating today.


Scattered showers are over the N Bahamas and the W Atlantic, N of
25N and W of 73W. A large 1027 mb high is centered over the
central Atlantic near 32N57W producing fair weather. As typical
for this time of year, tropical waves are moving through the
tropical Atlantic waters. Of note in the upper levels, an upper
level high is over the W Atlantic near 33N66W producing upper
level diffluence over Florida. An upper level low is also centered
over the W Atlantic near 25N49W enhancing showers NW of center.

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