[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201726 CCA
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
939 AM EDT Mon Aug 20 2018

Corrected Caribbean Sea section

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
1315 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis along 32W/33W
from 05N to 17N, moving westward at 10-15 kt. Isolated moderate
convection is from 05N to 17N. Scattered moderate convection is
within 180 nm east of the wave from 05N to 08N. Isolated showers and
thunderstorms are elsewhere within 180 nm either side of the wave
from 05N to 11N.

A central Atlantic tropical wave has its axis extending from
05N51W to 12N50.5W to 18N49W, moving westward at 10-15 kt.
Isolated showers and thunderstorms are within 120 nm either side
of the wave from 08N to 11N.

A Caribbean Sea tropical wave has its axis extending from far
southern Costa Rica northward to 15N77W and to eastern Cuba near
20N76W. It is moving westward at 10-15 kt. Isolated moderate
convection is within 60 nm east of the wave from 20N-21N.

The northern portion of an eastern Pacific tropical wave extends
along 91W northward to the far eastern Bay of Campeche, moving
westward near 15 kt. Only isolated showers are noted within 60 nm
of the wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from western Africa at 13N17W to
10N28W to 08N40W, where scatterometer data indicates the ITCZ axis
begins and extends to 08N49W where it briefly ends just east to
the east of the central Atlantic tropical wave. It resumes at
09N52W to just inland the coast of S America at 07N58W. Scattered
moderate convection is within 60 nm south of the axis between
17W and 20W. Widely scattered moderate convection is seen from 05N
to 09N between 26W and 29W. Isolated moderate convection is within 60 nm
of the ITCZ axis between 53W and 58W.

...DISCUSSION...

GULF OF MEXICO...

A 1023 mb high is centered over the W Atlantic at 32N59W, with a
ridge axis extending WSW from the high to central Florida and to
the eastern gulf waters. The associated gradient is allowing for
generally moderate southerly flow to persist over much of the
gulf, except for lighter SW to W flow, in the 5-10 kt range over
the far northeastern gulf waters. Widely scattered moderate
convection is over the N Florida Peninsula N of 27N. The northern
portion of a tropical wave is over the eastern Bay of Campeche.
No deep convection is occurring with this wave. See above for
details. Scattered moderate to isolated strong convection is from
15N to 21N between 92W and 95W. A small upper-level low is centered over the
Yucatan Channel near 22N86W enhancing the convection over western
Cuba and the NW Caribbean Sea.

Expect, a surface high to develop over the Gulf near 27N91W on
Tue. This high will meander over the western gulf waters through
Thu. A weak trough will stalls over the eastern Gulf waters, then
drifts west and dissipates on Fri.

CARIBBEAN SEA...Corrected

A tropical wave is over the western section of the central Caribbean.
See above for details. A surface trough has recently become evident
roughly along a position from 18N69W to near 10N72W. Latest
satellite imagery shows an area of increasing scattered moderate
convection within 60 nm east of the trough from 15N to 17N. This
activity is being further aided by an upper-level disturbance that
is quickly moving westward in moderate to strong east winds that are
located to the south of an upper anticyclone centered just north of
the Dominican Republic.
Otherwise, surface ridging extending from the Atlantic to the
northern half of the basin supports fresh to strong winds in the
south-central Caribbean.

Expect scattered showers and thunderstorms to persist over the
southwestern Caribbean through at least Wed. Also expect strong to
near gale force nocturnal easterly trades expected along the
northwestern coast of Colombia and across the Gulf of Venezuela
through the middle of the week.

ATLANTIC OCEAN...

A surface trough is analyzed from near 32N51W to 28N62W. Another surface trough
is analyzed from near 32N45W to 22N55W. Meanwhile, a small upper-level
low is near 28N62W. The combination of a very moist and unstable atmosphere
and upper divergence to the east and southeast of the low is leading
to scattered moderate convection from 25N-29N between 61W and 65W. Isolated
showers and thunderstorms are seen within 60 nm south of the first
trough between 57W and 62W. Yet another surface trough is analyzed
along a position from near 28N69W to the southeastern Bahamas near 22N74W.
A shortwave trough passing just to its northwest is providing additional
atmospheric lift leading to clusters of scattered moderate convection from
26N to 29N and between 71W and 74W. Isolated showers and thunderstorms are
elsewhere within 90 nm of the surface trough from 22N to 26N. The trough from
28N69W to the southeastern Bahamas is forecast to move westward across the
Bahamas through Wed. An upper-level anticyclone is identified to be just north
of the Dominican Republic near 21N70W. Its associated subsidence is suppressing
deep convection from developing in that general area, however, a narrow band of
broken to overcast low and mid-level clouds with scattered showers and isolated
thunderstorms is noted from just along the coast of Hispaniola northward to
21N and between 69W and 72W.

E of the lower Windward Islands, scattered moderate convection is seen within 30 nm
either side of a line from 09N58W to 11N61W. A 1023 mb high is centered over the
western Atlantic near 32N59W. A 1026 mb high is centered to the southwest of the Azores
near 37N31W. It is allowing for ridging and generally fair weather to persist over the
eastern Atlantic.

The trough north of the central Bahamas is forecast to move westward across the
Bahamas through Tue night.

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

$$
Aguirre
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