[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141804
TWDAT

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

...SPECIAL FEATURES...

Tropical Storm Humberto is centered near 26.6N 76.7W at 14/1500
UTC or 30 nm ENE of Great Abaco Island. Humberto has barely moved
this morning remaining stationary with a minimum central pressure
of 1005 mb. Maximum sustained wind speed is 45 kt with gusts to
55 kt.

Scattered moderate isolated strong convection extends outward 180
nm NE and E quad. Numerous moderate to scattered strong convection
extends outward 270 nm SE quad. Little to no convection is in the
western semicircle. On the forecast track, the center of Humberto
should gradually move away from the northwestern Bahamas later
today or tonight, and then will 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...

An eastern Atlantic tropical wave is along 34W from 05N-15N,
moving W at 15-20 kt. The wave is well depicted in satellite
imagery and TPW imagery. Scattered moderate convection is from
06N-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 is along 46W from 20N southward,
moving W at 15-20 kt. Scattered showers are within 180 nm west of
the wave axis from 12N-17N. This wave is well depicted in model
guidance, and satellite imagery shows turning. Conditions could
become a little more conducive for development in a few days when
the wave moves over the eastern Caribbean Sea.

An Atlantic tropical wave is along 57W, from 21N southward, moving
west around 15 kt. Scattered moderate convection is within 100 nm
of the wave axis from 13N-17N. TPW imagery and 700 mb streamline
analysis depict the wave well.

A western Caribbean tropical wave is along 87W from 18N southward,
moving W around 15 kt. Scattered showers are over the Gulf of
Honduras, and over portions of Central America.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Guinea-Bissau near 12N16W to
09N20W to 08N42W. The ITCZ is from 06N49W to 04N56W. Aside from
the convection already discussed in the Tropical Waves section, an
area of moderate isolated strong convection embedded in the monsoon
trough extends 180 nm North between 21W-33W. This elongated area of
disturbed weather is being monitored with a low chance of tropical
cyclone formation during the next 48 hours. An area of scattered
moderate convection, associated with a surface trough, is just N
of the ITCZ from 08N-11N between 49W-54W. Elsewhre, scattered
showers are within 100 nm N of the ITCZ.

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, but spans nearly the entire Gulf. Upper-level
diffluence on the east/northeast side of the upper low is producing
numerous moderate isolated strong convection from 24N-29N between
82W-91W. Only slow development of this system is likely during
the next couple of days. However, conditions could become more
conducive for development early next week as the system moves over
the western Gulf of Mexico.

Elsewhere across the basin, scattered showers and tstorms are
seen near the coast of Mexico from 18N93W to 24N97W. The latest
ASCAT pass shows moderate to fresh ENE winds across much of the
Gulf.

A large area of showers and thunderstorms over the eastern Gulf
of Mexico is primarily associated with a upper-level low. Only
slow development of this system is likely during the next couple
of days. However, conditions could become more conducive for
development early next week as the system moves over the western
Gulf of Mexico. Fresh to locally strong NE to E winds will persist
over the eastern Gulf today, between high pressure over the
Mississippi Valley and Tropical Storm Humberto near the Bahamas.
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 wave moving across the western Caribbean.

Relatively dry air covers much of the Caribbean Sea, including
the central Caribbean. In the SW Caribbean, a line of scattered
moderate strong convection extends from the NW coast of Colombia
to the coast of Nicaragua, from 08N-16N between 76W-83W. Surface
trough extends north of Cuba and the NW Caribbean from 23N79W to
21N86W. Scattered showers and tstorms are also seen over the NE
Caribbean due to an approaching tropical wave. The latest ASCAT
pass shows fresh trades over the south-central Caribbean, south
of 16N between 64W-77W.

Moderate to fresh trade winds will dominate much of the basin,
with fresh to strong winds in the south-central Caribbean through
Sun. A tropical wave over the Gulf of Honduras will move inland
today. Another tropical wave nearing Barbados 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 north of 23N-59W to 31N53W.
Upper-level diffluence near the base of this trough is giving way
21N-24N between 60W-63W with a trough at the surface 23N66W to
28N61W. Some additional showers are seen within 150 nm of a line
extending from 23N57W to 28N51W to 31N49W due to low-level troughing
and upper-level diffluence in the area. Surface ridging and fair
weather cover E Atlantic north of 20N and east of 40W.

Tropical Storm Humberto will move to 27.6N 77.6W this evening,
28.7N 78.1W Sun morning, strengthen to a hurricane near 29.5N
78.0W Sun evening, 30.0N 77.0W Mon morning, and 30.5N 74.5W Tue
morning. Humberto will change little in intensity as it moves to
the near 31.5N 70.0W early Wed, and continue to near 34.5N 63.0W
on Thu. The center of Humberto should gradually move away from the
NW Bahamas later today or tonight, and then will 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. Northerly swell will reach
the Atlantic passages into the Caribbean Sea late on Mon.

$$

Torres
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