[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 PM EDT Thu Oct 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...TROPICAL WAVES...

A tropical wave is in the central Atlc with axis extending from
18N33W to 06N36W, moving W at 20 kt. Satellite derived data
indicate the wave is in a strong vertical wind shear environment.
However, deep layer moisture and middle to upper level diffluent
flow support scattered heavy showers and isolated tstms from 13N-21N
between 30W-39W.

A tropical wave is in the E Caribbean with axis extending from
18N63W to 07N64W, moving W at 5 kt. The wave is in a region of strong
vertical wind shear. However, abundant low to middle level moisture
along with upper level diffluent flow in the SE basin support
scattered heavy showers and isolated tstms from 08N-14N between
57W-65W.

A tropical wave is in the central Caribbean with axis extending
from 18N69W to inland Venezuela near 08N70W, moving W at 10 kt.
The wave is in a region of strong vertical wind shear and CIRA LPW
imagery show patches of dry air in the wave environment. The wave
is underneath an upper level low that supports isolated showers from
14N to 18N between 67W-72W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 07N12W to
07N20W to 08N26W. The Intertropical Convergence Zone axis extends
from 09N40W to 08N59W. Aside from the convection associated with
the tropical wave in the central Atlc, scattered showers are from
07N-14N between 40W-60W.

...DISCUSSION...

GULF OF MEXICO...

Surface high pressure has built across the basin in the wake of a
former stationary front that dissipated early this morning. The
ridge is being anchored by a 1027 mb high located in the border
between Tennessee and North Carolina. A weakness in the
ridge...remnants of the front...is analyzed in the W Gulf as a
surface trough, which extends along 28N96W to the Bay of Campeche
near 18N94W. Shallow moisture and middle level divergent flow the
Bay of Campeche support scattered heavy showers and tstms S of 20N
between 93W and 95W. Isolated showers are noted in the NW basin
within 210 nm either side of the trough axis and in the central
basin from 23N-25N between 87W-91W. Moderate to occasional fresh
E-NE winds are expected today and through Saturday as the surface
ridge remains in place.

CARIBBEAN SEA...

An upper level anticyclone is centered NE of Honduras providing
an overall divergent environment aloft over the western Caribbean
W of 80W. Scattered heavy showers and tstms are occurring beneath
the upper level feature...however, associated with a surface
trough along the Yucatan Peninsula and Belize coasts. In the SW
basin S of 15N W of 78W, numerous heavy showers and tstms
developed associated with a 1009 mb low in the the monsoon trough
near 10N80W. This convection extends W to inland Nicaragua.
Scattered moderate convection is in the north-central and SE
Caribbean associated with two tropical waves. See tropical waves
section. Otherwise, fresh to strong trades prevail E of 76W and
are expected to gradually expand westward through Sunday as the
pressure gradient strengthens from high pressure anchored across
the western North Atlc.

...HISPANIOLA...

A pair of tropical waves will skirt S of the island through
Friday bringing scattered showers and isolated tstms to southern
portions of the island and the southern adjacent coastal waters.
By Friday, fresh to strong trades are expected as high pressure
builds in across the region.

ATLANTIC OCEAN...

A stationary front extends from 31N69W to 28N74W to northern-central
Cuba near 23N80W. The front is underneath diffluent flow aloft,
which is supporting scattered heavy showers and tstms within 210
nm E of the boundary. This convection is also supported by a
surface trough along 29N67W to 23N76W. The remainder of the
central and eastern Atlc are under the influence of a surface
ridge anchored by a 1027 mb high centered near 31N32W.

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

$$
Ramos
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