[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120605
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 AM EDT Wed Jul 12 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
0545 UTC.

...TROPICAL WAVES...

A tropical wave is in the E Atlc with axis extending from 13N19W
to 04N19W. The wave is in a region of favorable wind shear,
however extensive intrusion of Saharan dry air and dust are
hindering deep convection. Shallow moisture and middle to upper
level diffluence support scattered to isolated showers from 06N to
11N E of 21W.

A tropical wave is in the central Atlc with axis extending from
14N39W to 05N39W, moving W at 15-20 kt within the last 24 hours. The
wave is in a region of neutral to favorable wind shear, however
extensive intrusion of Saharan dry air and dust are hindering deep
convection. Shallow moisture support isolated showers from 09N to
12N between 34W and 45W.

A tropical wave is just E of the Lesser Antilles with axis
extending from 19N59W to 10N59W, moving W at 20-25 kt within the
last 24 hours. The wave is in a region of favorable wind shear,
however deep layer dry air hinder deep convection at the time.

A tropical wave is over the central Caribbean Sea with axis
extending from 20N77W to 10N77W, moving W at 15 kt within the
last 24 hours. The wave is in a region of unfavorable wind shear
and CIRA LPW imagery show large patches of dry air in its
environment, which limit the convection to scattered showers from
11N to 18N between 74W and 85W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the coast of W Africa near 15N17W
to 09N21W to 08N35W. The ITCZ begins near 07N40W and continues to
09N57W. Aside from the convection associated with the tropical
waves, numerous heavy showers and scattered tstms are from 04N to
08N between 26W and 32W and from 07N to 12N between 48W and 54W.

...DISCUSSION...

...THE GULF OF MEXICO...

A weak surface ridge continues to dominate the Gulf waters
producing mainly gentle to moderate E-SE winds. This ridge and
wind pattern will persist through Thursday morning. In the NE
Gulf, remnants of a former surface trough, shallow moisture in
the region and middle level diffluence support isolated showers N
of 26N E of 87W. Similar convection is in the E Bay of Campeche
being supported by a tropical wave that moves across southern
Mexico and adjacent EPAC waters. Looking ahead, a surface trough,
associated with the remnants of T.D Four, currently located over
the SW N Atlc, will move across south Florida on Thursday, and
across the E Gulf Thursday night into Friday, reaching the central
Gulf later on Friday. This trough is expected to increase the
likelihood of showers with embedded thunderstorms.

...THE CARIBBEAN SEA...

The main feature in the basin is a tropical wave moving across
the central Caribbean waters, which is supporting scattered to
isolated showers. Another tropical wave is just E of the Lesser
Antilles and is expected to enter the basin later this morning
with possible isolated showers. See the waves section above for
further details. The latest scatterometer pass continue to
provide observations of fresh to strong winds over the south-
central Caribbean S of 13N between 70W and 74W, including the Gulf
of Venezuela. The area of strong trade winds is shrinking
slightly as high pressure north of the region weakens. Heavy
showers and thunderstorms continue over the eastern half of Panama
and SW Caribbean waters between Panama and Colombia S of 11N.
This convection is mainly being supported by the EPAC monsoon
trough. Looking ahead, a stronger tropical wave is forecast to
approach the Windward Islands late Thursday and enter the eastern
Caribbean early on Friday.

...HISPANIOLA...

Available moisture will combined with the local effects to produce
scattered showers and isolated and thunderstorms during the
afternoon and early evening hours today Wednesday and Thursday.
An upper-level low will support these showers, which is forecast
to dissipate afterwards while moving west towards E Cuba.

...THE ATLANTIC OCEAN...

The remnants of T.D. Four continue situated in the SW N Atlc
waters while it further weakens. A 1016 mb low pressure is
associated with it, which is located near 23N70W along with a
surface trough that extends from 28N69W to the low to 21N69W. Scattered
showers and isolated thunderstorms area within 150 nm of the low
center. Model guidance continue to suggest that a trough
associated with the remnants of T.D. Four will move across the
Bahamas through Wednesday night, reaching south Florida on
Thursday. A surface trough extends from 30N74W to 23N77W.
Scattered showers and tstms are from 23N to 28N between 74W and
80W. Otherwise, the Bermuda-Azores high extends a ridge across
the remainder of the forecast region.

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

$$
Ramos
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