Tropical Weather Discussion
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AXNT20 KNHC 180601

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
201 AM EDT Tue Jul 18 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
0515 UTC.


Tropical Storm Don is east of the Windward Islands. On 18/0300
UTC, the location of the storm center is near 11.3N54.6W or about
308 nm ESE of Barbados, and has a minimum central pressure of
1009 mb. Don is moving westward at 16 kt. Maximum sustained winds
are 40 kt with gusts to 50 kt. The center of Don will move through
the Windward Islands late Tuesday and Tuesday night. Don is
expected to produce total rain accumulations of 2 to 4 inches
across the Windward Islands through Wednesday morning. Please
refer to the latest NHC forecast/advisory under AWIPS/WMO headers
MIATCPAT5/WTNT35 KNHC for more details.


A tropical wave is in the central Atlc with axis extending from
18N37W to a 1013 mb low near 10N38W to 05N37W, moving west at 20
kt. A 18/0011 UTC scatterometer pass depicted the low center well.
The SSMI total precipitable water imagery shows a very moist area
S of 15N. The wave is in a region of neutral to unfavorable wind
shear and dry air intrusion to its environment well NW of the low
center. Scattered moderate to isolated strong convection is from
10N-12N between 37W-40W. Some gradual development of this system
is possible over the next few days while it moves slowly W over
the open Atlantic Ocean.

A tropical wave is just east of the Lesser Antilles with axis
extending from 20N58W to 08N59W, moving west at 20 kt. The wave
is mainly in a region of neutral to unfavorable wind shear, and
Saharan dry air and dust is noted W of 62W. Scattered showers are
within 90 nm of the wave axis.

A tropical wave is in the west Caribbean with axis extending
from 21N86W to 12N89W, moving west at 5 to 10 kt. SSMI total
precipitable water imagery shows a very moist area over Central
America. Numerous strong convection is presently from 11N-17N
between 87W-91W, especially over El Salvador.


The monsoon trough extends from 12N16W to 10N22W to 12N30W to
08N43W to 08N50W. Aside from the convection associated with the
tropical waves, isolated moderate convection is off the coast of W
Africa from 08N-10N between 14W-19W. Similar convection is off the
coast of South America from 03N-09N between 43W-50W.



A surface trough is over the Bay of Campeche from 22N90W to
17N93W. Scattered moderate convection is within 60 nm of the
trough axis. The remainder of the Gulf of Mexico has weak surface
ridging 5-10 kt southerly flow. Radar imagery shows scattered
showers over S Florida and the Straits of Florida. Similar showers
extend from SE Louisiana to the Florida Panhandle. Lightning
detection system shows isolated thunderstorms over the W Gulf
between 90W-96W. In the upper levels, an upper level low is
centered over Tampico Mexico near 21N97W. Upper level diffluence E
of the center is enhancing convection over the Yucatan Peninsula.
Expect little change over the next 24 hours.


A tropical wave is moving through the western Caribbean and
Central America, with convection. See above. Further south,
scattered moderate to isolated strong convection is along the
coast of Nicaragua from 11N-13N between 80W-85W. Of note in the
upper levels, a small upper level low is centered S of Cuba near
19N80W. Expect tropical storm Don to move through the Windward
Islands starting late Tuesday. See above.


Presently scattered showers remain over Hispaniola. Upper level
diffluence is enhancing these showers. Expect conditions to
improve Tuesday.


Scattered showers are over the N Bahamas and the W Atlantic, N of
25N and W of 76W. A large 1032 mb high is centered over the
central Atlantic near 34N42W producing fair weather. As typical
for this time of year, tropical waves are moving through the
tropical Atlantic waters. See above. Of note in the upper levels,
an upper level low is centered over the W Atlantic near 32N68W
enhancing showers.

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