[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131718
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
118 PM EDT Fri Sep 13 2019

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.

...SPECIAL FEATURES...

The center of Potential Tropical Cyclone Nine is centered near
25.0N and 74.5W at 13/1500 UTC, or 240 nm ESE of Freeport Grand
Bahama Island, moving NW at 1 kt. Estimated minimum central
pressure is 1009 mb. Maximum sustained wind speed is 25 kt with
gusts to 35 kt. Scattered showers and thunderstorms are within
240 nm of the center in the E quadrant. On the forecast
track, the system is anticipated to move across the central and
northwestern Bahamas today, and along or near the east coast of
Florida Saturday and Saturday night. The disturbance is forecast
to become a tropical depression, or a tropical storm later today
or Saturday. The chance of tropical cyclone formation during the
next 48 hours is high. Please, read the latest NHC
forecast/advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC,
or go to the website hurricanes.gov, for more details.

...TROPICAL WAVES...

A tropical wave has been introduced to this analysis, with axis
extending along 27N from 06N-20N. This wave has been moving west
at around 10-15 kt. The wave is well depicted in satellite
imagery and TPW imagery. Scattered moderate convection is
developing in the wave's environment mainly south of 12N between
28W-32W. Conditions are expected to become more conducive for
development in a couple days, and a tropical depression could form
early next week while the system moves westward across the
tropical Atlantic.

A central Atlantic tropical wave extends its axis along 39W from
06N-20N, moving west at 10 to 15 kt. Scattered moderate convection
is noted from 12N20N between 37W-43W. This wave is well depicted
in model guidance and a satellite signature is noted. Conditions
are expected to become more conducive for development in a couple
days with this system also, and a tropical depression could form
early next week while the it moves westward across the tropical
Atlantic.

Another Atlantic tropical wave is analyzed with axis along 53W,
from 08N-21N, moving west at 10-15 kt. This wave was repositioned,
based on satellite signature, TPW imagery and 700 mb streamline
analysis. At this time, scattered showers are confined to the
wave axis, mainly from 14N-17W.

A west Caribbean tropical wave extends its axis along 81W from
07N-19N, moving west at around 10 kt. Numerous showers and
thunderstorms are developing south of 13N between 78W-83W. This
activity is enhanced by the presence of the monsoon trough,
currently along 10N.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal Africa near 17N17W to
07N43W. Aside from the convection already discussed in the
Tropical Waves section above, scattered showers are noted along
the boundary between 22W-28W.

GULF OF MEXICO...

An upper-level low is centered over the northeast Gulf, enhancing
convection east of 90W. To the west, a surface trough extends
across the Bay of Campeche from 23N97W to 20N94W. Scattered
showers are noted along the trough. Scatterometer data depicts
light to gentle winds across the western half of the basin, while
gentle to moderate winds prevail east of 90W.

High pressure over the southeastern United States
will support moderate to fresh northeast to east winds into the
weekend. Potential Tropical Cyclone Nine will track northwestward
off the east coast of Florida through early next week. The
gradient between the cyclone and the high pressure will allow for
fresh winds over the NE Gulf today through Sat, along with
building seas. Scattered showers and thunderstorms are expected
across the eastern Gulf through Sun.

CARIBBEAN SEA...

Refer to the section above for details on the tropical wave moving
across the west Caribbean.

Scattered showers are noted over the Yucatan Channel and western
Cuba. Aside from the convection related to the tropical wave over
the southwest portion of the basin, fair weather prevails
across the area. Scatterometer data depicts gentle to moderate
trades across the basin, except locally fresh winds south of 14N
between 68W-72W.

High pressure north of the area will maintain
moderate trades, that will at times pulse to fresh to strong in
the south central Caribbean. The tropical wave will move across
Central America on Sat. The next tropical wave will move across
the eastern Caribbean on Sat. A third and stronger tropical wave
will approach the eastern Caribbean over the weekend into early
next week, expected to bring widespread showers and thunderstorms,
gusty winds and building seas.

ATLANTIC OCEAN...

Refer to the sections above for details on the Potential T.C Nine,
and the 3 tropical waves moving across the basin.

Upper level cyclonic wind flow covers the area north of 25N
between 50W and 64W. A surface trough is analyzed from 33N52W to
28N57W with scattered showers. Surface ridging prevails across the
remainder of the basin with fair weather.

Potential Tropical Cyclone Nine will move to 25.8N 76.5W this
evening, 26.6N 78.0W Sat morning, 28.0N 79.4W Sat evening, 29.2N
80.0W Sun morning, and 31.0N 79.0W Mon morning. Nine will change
little in intensity as it moves to near 31.5N 75.0W early Tue, and
continue to near 32.0N 71.5W Wed. Elsewhere, the next tropical
wave may approach the waters south of 22N by early next week.

$$

ERA
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