[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021706
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
106 PM EDT Mon Oct 2 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
1700 UTC.

...TROPICAL WAVES...
A tropical wave over the Eastern Atlantic extends from 04N29W to
13N26W moving W at 20 to 25 kt. The wave remains low amplitude and
coincides with modest troughing at 700 mb. Satellite TPW imagery
indicates this wave is embedded in an area of deep-layer moisture.
Scattered moderate and isolated strong convection is seen from
09N to 13N between 26W and 31W.

A tropical wave over the Central Atlantic extends from 09N50W to
21N55W moving W at 15 to 20 kt. The wave coincides with broad
troughing at 700 mb. The wave continues to interact with an upper-
level low that has been moving in tandem with the wave and is
currently centered near 17N51W. Divergent upper-level winds on the
east side of the upper-level low are supporting a large area of
scattered moderate and isolated strong convection from 10N to 22N
between 40W and 51W.

A tropical wave over the Central Caribbean extends from 07N77W to
17N75W moving W at 5 to 10 kt. The wave coincides with pronounced
troughing at 700 mb. This wave is also interacting with an upper-
level low currently centered just south of Jamaica near 17N77W.
Scattered moderate and isolated strong convection is found from
08N and 16N between 73W and 83W.

...ITCZ/MONSOON TROUGH...
The monsoon trough extends from near 07N16W to 06N32W. The
Intertropical Convergence Zone continues from 06N32W to 06N38W to
11N49W, then resumes from 09N53W to 09N61W. Scattered moderate
convection is taking place from 06N to 09N between 56W and 61W.

...DISCUSSION...

GULF OF MEXICO...
A weakening frontal boundary crosses the NE Gulf from near Tampa
Florida to the Mouth of the Mississippi River. Scattered showers
and isolated tstms associated with the front are occurring N of
28N between 84W and 91W. Satellite-derived wind data continue to
indicate strong ENE winds to the north of the boundary. The
boundary will continue to weaken during the next couple of days as
surface ridging builds across the SE CONUS...NE Gulf waters...and
SW North Atlc waters. As a result, a stronger pressure gradient
and increased E winds will affect the NE Gulf. By Monday night
into early Tuesday areal coverage of this wind field is expected
to expand and influence the northern two-thirds of the basin as
fresh to strong easterly winds will prevail.

An upper-level low is centered along the southern shore of the
Bay of Campeche near 20N92W. The low is inducing broad cyclonic
flow at the surface over the Western Gulf of Mexico. Sharper
troughs are embedded in this area of broad cyclonic flow along the
western shore of the Bay of Campeche and from just west of the
Yucatan Peninsula to south of the Mouth of the Mississippi.
Scattered moderate and isolated strong convection is present over
and north of the Yucatan from 19N to 25N between 86W and 91W. The
upper-level low is expected to slowly shift toward the SW during
the next couple of days. As it does so, the convection and
troughing over the western Gulf will move farther west in tandem
with the upper-level low.

Furthermore...a small surface trough over the NW is producing a
small area of showers and thunderstorms from 27N to 28N between
91W and 94W. The trough is expected to move inland over Texas and
dissipate tonight.

CARIBBEAN SEA...
A pair of upper-level lows continue to drive virtually all of the
ongoing active weather and convection over the basin. One upper-
level low centered over the SW Gulf of Mexico near 20N92W is
supporting scattered showers and isolated tstms just east of the
Yucatan Peninsula over the far western Caribbean west of 86W.
Farther east, the second upper-level low centered near 17N77W
continues to interact with a tropical wave analyzed from 07N77W to
17N75W to produce scattered showers and isolated tstms south of
16N between 73W and 83W. Otherwise...light to moderate E-SE trades
will persist through Monday night.

...HISPANIOLA...
Currently the island remains under the influence of an upper
level low centered near 17N77W and a tropical wave moving W in
tandem with the upper-level low. The upper-level low will move SW
ahead of the tropical wave and continue interacting with it to
generate scattered showers and isolated tstms across the region
through tonight. Drier weather is expected by Tuesday night as
the tropical wave and low move farther west. To the north of the
island...a surface trough extends from 18N74W to 23N71W. There is
no longer significant deep convection associated with this trough.

ATLANTIC OCEAN...
A frontal boundary extends SW into the discussion area from
32N59W SW into a weakening 1014 mb low centered near 27N73W,
continues as a weakening boundary to 25N76W to the Florida coast
near 26N80W. Cloudiness and scattered showers are observed along
the front and northward to 30N. This front lies to the south of a
strong ridge anchored by a 1029 mb high centered over Virginia.
Otherwise...broad surface ridging extends SW from a 1029 mb high
centered E of the Azores near 38N24W.

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

$$
McElroy
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