[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181018
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
618 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 0600 UTC surface analysis and satellite imagery through
1015 UTC.

...SPECIAL FEATURES...

Tropical Storm Don is east of the Windward Islands. On 18/0900
UTC, the location of the storm center is near 11.5N56.2W or about
217 nm ESE of Barbados, and has a minimum central pressure of
1007 mb. Don is moving westward at 16 kt. Maximum sustained winds
are 45 kt with gusts to 55 kt. Scattered moderate to isolated
strong convection is from 10N-13N between 55W-58W. The center of
Don will move through the Windward Islands tonight. Don is
expected to produce total rain accumulations of 3 to 6 inches
across Barbados and the southern Windward Islands through
Wednesday morning. These rains could produce life-threatening
flash floods and mudslides, especially in mountainous areas.
Please refer to the latest NHC forecast/advisory under AWIPS/WMO
headers MIATCPAT5/WTNT35 KNHC for more details.

...TROPICAL WAVES...

A tropical wave is in the central Atlc with axis extending from
17N37W to a 1013 mb low near 10N38W to 05N38W, moving west at 10
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 has dry air intrusion to its environment well NW of the
low center. Scattered moderate convection is from 10N-12N between
38W-41W. 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 over the E Caribbean with axis extending from
20N61W to 08N62W, 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 63W. Scattered showers are within 90 nm of
the wave axis.

A tropical wave is over Central America and the E Pacific with
axis extending from 22N88W to 10N89W, moving west at 5 to 10 kt.
SSMI total precipitable water imagery shows a very moist area over
Central America. Scattered moderate to isolated strong convection
is presently from 10N-17N between 88W-92W, especially over
Guatemala.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from 12N16W to 09N22W to 13N30W to
07N46W. Aside from the convection associated with the tropical
wave, isolated moderate convection is off the coast of W Africa
from 07N-11N between 15W-22W. Similar convection is off the coast
of South America from 04N-08N between 43W-51W.

...DISCUSSION...

GULF OF MEXICO...

A surface trough is over the Bay of Campeche from 21N91W to
16N93W. Scattered showers are within 60 nm of the trough axis.
Further W, scattered moderate convection is over Veracruz Mexico
from 17N-21N between 94W-97W. 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 over the N Gulf N of 27N. 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.

CARIBBEAN SEA...

A tropical wave is moving through Central America, with
convection. See above. Further south, scattered moderate to
isolated strong convection is over the SW Caribbean from 07N-13N
between 79W-83W. 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 tonight. See above.

...HISPANIOLA...

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

ATLANTIC OCEAN...

Scattered showers are over the N Bahamas and the W Atlantic, N of
25N and W of 76W. A large 1030 mb high is centered over the
central Atlantic near 34N43W 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.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Formosa
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