[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142340
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
740 PM EDT Sat Sep 14 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 1800 UTC surface analysis and satellite imagery through
2330 UTC.

...SPECIAL FEATURES...

Tropical Storm Humberto is centered near 27.4N 77.3W at 14/2100
UTC, or 60 nm N of Great Abaco Island, moving NNW at 6 kt.
Estimated minimum central pressure is 1005 mb. Maximum sustained
wind speed is 45 kt with gusts to 55 kt. Scattered to numerous moderate
convection extends from 23N-30N between 71W-80W. On the forecast track,
the center of Humberto should continue to move away from the
northwestern Bahamas tonight, and then move well offshore of the
east coast of Florida this weekend and early next week. Humberto
is forecast to become a Hurricane by Sunday night well east of the
east coast of Florida. Please read the latest NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC,
or go to the website hurricanes.gov for more details.

...TROPICAL WAVES...

A central Atlantic tropical wave with axis along 36W from 05N-
15N, is moving W at 10-15 kt. The wave is well depicted in
satellite imagery and TPW imagery. Scattered moderate convection
is from 09N-12N between 32W-36W. Gradual development of this
system is possible during the next several days, and a tropical
depression could form early next week while it moves westward
across the tropical Atlantic.

A central Atlantic tropical wave with axis along 50W from 08N-
21N, is moving W at 15-20 kt. Scattered showers are within 180 nm
west of the wave axis from 12N-20N. This wave is well depicted in
model guidance and satellite imagery.

A tropical wave is approaching the Lesser Antilles, with axis
extending from 20N58W to 07N60W, moving west around 10-15 kt.
Scattered showers are noted along the wave axis mainly north of
16N. This wave is well depicted in satellite and model guidance
also.

The northern extension of a tropical wave is currently over the
Yucatan Peninsula with axis along 89W and south of 19N, moving W
around 10 kt. Scattered showers are noted within 75 nm on either
side of the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Guinea-Bissau near 12N17W to
07N43W. A surface trough was noted in scatterometer data from
11N55W to 06N53W. Aside from the convection already discussed in
the Tropical Waves section above, scattered showers are noted
within 90 nm to the north of the monsoon trough.

GULF OF MEXICO...

The weather over the Gulf of Mexico is dominated by a large
upper-level low that is centered over the central portion of the
basin near 25N91W. Upper-level diffluence on the east side of the
upper-low is producing numerous moderate convection from 24N-29N
and east of 92W. Only slow development of this system is likely
during the next couple of days while it moves westward over the
western Gulf of Mexico. This system is forecast to move inland
along the northwestern Gulf coast by late Monday or Tuesday and
development is not expected after that time. The latest ASCAT
pass depicts moderate to fresh easterly winds across the northern
half of the basin, while light to gentle winds prevail over the
southern half.

Winds and seas will diminish tonight into Sun as Humberto moves
away from the eastern coast of Florida.

CARIBBEAN SEA...

Refer to the Tropical Waves section above for details on the
tropical waves moving and approaching the basin.

Relatively dry air covers much of the Caribbean. In the SW
Caribbean, a line of scattered moderate convection extends from
the northwest coast of Colombia to the coast of Nicaragua, from
10N-16N between 78W-83W. A surface trough extends across the
Yucatan Channel with scattered showers. Scattered showers are
also noted over the northeast Caribbean due to an approaching
tropical wave. The latest ASCAT pass depicts gentle to moderate
trades across the basin.

Moderate to fresh trade winds will pulse across the basin, with
fresh to strong winds in the south-central Caribbean through Sun.
A tropical wave will move across the eastern Caribbean tonight and
Sun, reaching the central Caribbean on Mon. A third and stronger
tropical wave will approach Barbados late on Sun, move across the
eastern Caribbean Mon, and into the central Caribbean through mid
week, bringing widespread showers and thunderstorms, gusty winds
and building seas. Northerly swell will reach the Atlantic
passages into the Caribbean Sea late on Mon.

ATLANTIC OCEAN...

Refer to the sections above for details on T.S. Humberto and the
three tropical waves moving across the basin.

Upper-level troughing covers the area from 23N59W to 31N53W.
Upper- level diffluence near the base of this trough is enhancing
convection north of 20N between 50W-65W. A surface trough was
noted in scatterometer data from 28N61W to 23N66W. To the east, a
1018 mb high is centered near 28N46W. Surface ridging and fair
weather covers the east Atlantic north of 20N and east of 40W.

Tropical Storm Humberto will move to 28.2N 77.9W Sun morning,
29.3N 78.3W Sun afternoon, strengthen to a hurricane near 29.9N
77.9W Mon morning, 30.5N 76.7W Mon afternoon, and 31.2N 73.5W Tue
afternoon. Humberto will change little in intensity as it moves
near 32.5N 67.5W Wed afternoon, and continue to 36.0N 61.0W Thu.
The center of Humberto should continue to move away from the
northwestern Bahamas tonight, and then move well offshore of the
east coast of Florida this weekend and early next week. Humberto
is forecast to become a hurricane by Sunday night or early Monday
well east of the east coast of Florida. Northerly swell will reach
the Atlantic passages into the Caribbean Sea late on Mon.

$$

ERA
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