[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190554
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Aug 19 2021

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0550 UTC.

...SPECIAL FEATURES...

Hurricane Grace is centered near 19.9N 86.4W at 19/0600 UTC or
50 nm ESE of Tulum Mexico moving W at 16 kt. Estimated minimum
central pressure is 986 mb. Maximum sustained wind speed is 70 kt
with gusts to 85 kt. Numerous moderate and scattered strong
convection is noted from 16N to 22N and between 81W to 88W. Peak
seas are currently near 30 ft near the center. A general westward
to west-northwestward motion is expected through Friday, followed
by a general westward to west-southwestward motion. On the
forecast track, Grace is expected to make landfall in the eastern
Yucatan Peninsula during the next six hours, move across the
Yucatan Peninsula today, and move over the southwest Gulf of
Mexico late tonight through Friday. Some strengthening is forecast
before landfall on the Yucatan Peninsula. Grace is expected to
weaken as it crosses Yucatan, but re-intensification is
anticipated when the center reaches the Gulf of Mexico. Seas up to
30 ft will continue near the center in the NW Caribbean until the
hurricane makes landfall in Yucatan and then redevelop to 30 ft
in the SW Gulf of Mexico on Friday. Please read the latest NHC
Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT2.shtml
and Forecast/ Advisory at
https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for more details.

Tropical Storm Henri is centered near 29.8N 68.5W at 19/0300 UTC
or 245 nm SW of Bermuda moving W at 8 kt. Estimated minimum
central pressure is 995 mb. Maximum sustained wind speed is 60 kt
with gusts to 75 kt. Peak seas are currently up to 20 ft near the
center. Numerous moderate and scattered strong convection is
noted from 27N to 31N and between 65W to 70W. A sharp turn to the
north is expected on Friday with a general northward motion
continuing into the weekend. Little change is strength is forecast
during the next day or so, but Henri is expected to become a
hurricane on Friday. Peak seas should continue near 20 ft through
Friday morning, before diminishing in our waters as Henri moves
northward. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more
details.

...TROPICAL WAVES...

An Atlantic tropical wave has its axis along 25W, south of 19N,
and it is moving W at 10-15 kt. Scattered moderate convection is
noted along its wave axis from 09N to 13N.

A second Atlantic tropical wave has its axis along 35W, south of
19N, and it is moving W at 10-15 kt. Scattered moderate convection
is observed along its wave axis from 07N to 13N.

A third Atlantic tropical wave has its axis along 54W, south of
20N, and it is moving W at around 15 kt. No significant deep
convection is currently associated with this wave.

A Caribbean tropical wave has its axis along 67W, south of 21N,
and it is moving W at around 15 kt. No significant deep
convection is currently associated with this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from Senegal near 15N16W to
12N30W and to 11N42W. The ITCZ then extends from 11N43W to
07N53W. Moderate scattered convection is noted south of the
monsoon trough and ITCZ to 03N and between the coast of Africa to
45W.

...GULF OF MEXICO...

Refer to the Special Features section above for details on
Hurricane Grace.

The Gulf of Mexico is located in the SW periphery of the broad
subtropical ridge over the Atlantic. This is resulting in fairly
tranquil weather conditions, outside of the outer rainbands of
Hurricane Grace and diminishing evening thunderstorms exiting the
Yucatan peninsula into the E Bay of Campeche. Moderate to fresh
easterly breezes prevail across the central, SE and W Gulf of
Mexico, including the Bay of Campeche, and seas of 3-6 ft. Gentle
to moderate SE winds and seas of 1-3 ft are prevalent in the NE
Gulf.

For the forecast, Hurricane Grace near 19.8N 85.6W 988 mb at 11 PM
EDT moving W at 16 kt. Maximum sustained winds 70 kt gusts 85 kt.
Grace will move inland to 20.3N 88.1W Thu morning, weaken to a
tropical storm near 20.6N 91.4W Thu evening, strengthen to a
hurricane near 20.7N 94.0W Fri morning, 20.5N 96.1W Fri evening,
move inland and weaken to a tropical storm near 20.0N 98.8W Sat
morning, and move inland and weaken to a tropical depression near
19.7N 101.6W Sat evening. Grace will dissipate late Sun. Winds and
seas will begin to increase across the southeastern Gulf ahead of
Grace tonight. These conditions will shift to west of 90W Thu
through late Fri night.

...CARIBBEAN SEA...

Refer to the Special Features section above for details on
Hurricane Grace.

Outside of the wind field of Hurricane Grace, a recent
scatterometer satellite pass depict fresh to strong trades across
the central and E Caribbean Sea, with the strongest winds located
in the south-central Caribbean, off the NW coast of Colombia.
Gentle to moderate trades are noted in the SW Caribbean and Gulf
of Honduras. Seas are 6-8 ft in the central Caribbean, 4-6 ft in
the E Caribbean and 2-4 ft in the rest of the basin.

For the forecast, Hurricane Grace near 19.8N 85.6W 988 mb at 11 PM
EDT moving W at 16 kt. Maximum sustained winds 70 kt gusts 85 kt.
Grace will move inland to 20.3N 88.1W Thu morning, weaken to a
tropical storm near 20.6N 91.4W Thu evening, strengthen to a
hurricane near 20.7N 94.0W Fri morning, 20.5N 96.1W Fri evening,
move inland and weaken to a tropical storm near 20.0N 98.8W Sat
morning, and move inland and weaken to a tropical depression near
19.7N 101.6W Sat evening. Grace will dissipate late Sun.
Elsewhere, fresh to strong trades will be over the central
Caribbean through early Thu.

...ATLANTIC OCEAN...

Please refer to the sections above for details on Tropical Storm
Henri and on the tropical waves moving across the basin.

The 1026 mb Azores-Bermuda subtropical ridge remains the dominant
feature in the tropical Atlantic outside of Tropical Storm Henri.
This is allowing for fairly tranquil weather conditions across the
basin. However, a few showers are noted east of the Lesser
Antilles from 13N to 16N and between 56W and 60W. The strong high
pressure system and lower pressures over NW Africa result in a
tight pressure gradient over the NE Atlantic. Recent scatterometer
satellite data show strong to near gale-force N-NE winds
surrounding the Canary Islands and off the coasts of Morocco and
Western Sahara. Seas in this area are in the 5-8 ft range. An
area of fresh to strong NE winds is noted 19N to 29N and between
35W and 50W, with seas of 5-8 ft. Winds in the rest of the basin
are moderate to fresh with seas of 2-5 ft.

For the forecast west of 65W, Tropical Storm Henri near 29.8N
68.5W 995 mb at 11 PM EDT moving W at 8 kt. Maximum sustained
winds 60 kt gusts 75 kt. Henri will move to 29.8N 69.9W Thu
morning, 30.0N 71.8W Thu evening, strengthen to a hurricane near
30.7N 72.7W Fri morning, 32.3N 72.8W Fri evening, 34.4N 71.8W Sat
morning, and 36.9N 70.7W Sat evening. Henri will change little in
intensity as it moves near 40.4N 69.4W late Sun. Elsewhere, high
pressure will persist across the forecast waters through the
period. Fresh east to southeast winds over the far southwest part
of the area will shift W to the Straits of Florida tonight.

$$
DELGADO
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