[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172300
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Wed Aug 18 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 1800 UTC surface analysis and satellite imagery through
2245 UTC.

...SPECIAL FEATURES...

Tropical Storm Grace is centered near 18.4N 77.9W at 17/2100 UTC
or 0 nm S of Montego Bay Jamaica moving W at 13 kt. Estimated
minimum central pressure is 1003 mb. Maximum sustained wind
speed is 45 kt with gusts to 55 kt. SCattered to numerous moderate
convection prevails from 15N-22N between 73W-82W. Peak seas are
currently at 16 ft. On the forecast track, the center of Grace
will continue to move near the northwestern coast of Jamaica for
the next few hours. Grace is forecast to move near or over the
Cayman Islands late tonight and early Wednesday, and then
approach the Yucatan peninsula of Mexico late Wednesday or early
Thursday.

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 30.4N 64.2W at 17/2100 UTC
or 120 nm SSE of Bermuda moving WSW at 2 kt. Estimated minimum
central pressure is 997 mb. Maximum sustained wind speed is 55
kt with gusts to 65 kt. Scattered moderate convection is from
28N-31N between 61W-66W. Maximum seas will reach 15 ft. A faster
motion toward the west is forecast by tonight, followed by a
motion to the west-northwest or northwest by late Thursday. On
the forecast track, the center of Henri should pass well to the
south of Bermuda through tonight. 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...

A far eastern Atlantic tropical wave extends its axis along 22N
from 03N to 20N, moving westward at 10-15 kt. Scattered moderate
convection is noted from 04N to 16N between 20W and 27W.

An eastern Atlantic tropical wave has its axis along 42W from
02N to 21N, moving westward near 15 kt. Scattered showers are
noted in the vicinity of the wave.

A central Atlantic tropical wave has its axis along 59W from 20N
southward to inland Guyana, moving westward at 10-15 kt.
Scattered showers and thunderstorms are noted south of 11N
between 58W to 62W.

A western Caribbean tropical wave has its axis along 88W from
19N southward, moving westward at 10-15 kt. Scattered showers
and thunderstorms are noted on the southern end of the wave axis
over the eastern Pacific.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from Senegal near 13N17W to
08N44W, then transitions to ITCZ from 08N44W to 08N53W. Aside
from the convection associated with the tropical waves, scattered
moderate convection is seen south of the monsoon trough from 02N
to 10N between 41W-36W.

...GULF OF MEXICO...

With Tropical Depression Fred continuing to move farther inland,
the gradient is relaxed over the Gulf of Mexico. Light and
gentle winds prevail across the basin, with seas of 2 to 3 ft. A
surface trough continues over the Bay of Campeche. No
significant convection is noted with the trough at this time.

Tropical Storm Grace will move to 18.9N 80.3W Wed morning,
strengthen to a hurricane near 19.4N 83.4W Wed afternoon, 20.0N
86.7W Thu morning, move inland and weaken to a tropical storm
near 20.5N 89.7W Thu afternoon, strengthen to a hurricane near
20.9N 92.2W Fri morning, and 21.2N 94.8W Fri afternoon. Grace
will weaken to a tropical storm while moving inland near 21.0N
99.5W Sat afternoon. Grace is forecast to move near or over the
Cayman Islands late tonight and early Wednesday, and then
approach the Yucatan peninsula of Mexico late Wednesday or early
Thursday. Winds and seas will begin to increase across the SE
waters ahead of Grace on Wed.

...CARIBBEAN SEA...

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

Outside of the wind field of Grace, latest ASCAT data passes
showed moderate to fresh winds in the eastern and central
Caribbean and light to gentle trades in the western Caribbean,
pulsing to moderate in the Gulf of Honduras. Seas are 5-7 ft in
the east-central Caribbean, 4-6 ft near the Windward Islands,
3-5 ft near the Leeward Islands and in the west-central
Caribbean, and 3 ft or less in the western Caribbean.

For the forecast, Tropical Storm Grace will move to 18.9N 80.3W
Wed morning, strengthen to a hurricane near 19.4N 83.4W Wed
afternoon, 20.0N 86.7W Thu morning, move inland and weaken to a
tropical storm near 20.5N 89.7W Thu afternoon, strengthen to a
hurricane near 20.9N 92.2W Fri morning, and 21.2N 94.8W Fri
afternoon. Grace will weaken to a tropical storm while moving
inland near 21.0N 99.5W Sat afternoon. Grace is forecast to move
near or over the Cayman Islands late tonight and early Wednesday,
and then approach the Yucatan peninsula of Mexico late Wednesday
or early Thursday. Elsewhere, fresh to strong trades will be
over the central Caribbean through Wed night.

...ATLANTIC OCEAN...

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

The tight pressure gradient in the eastern Atlantic near the
Canary Islands continues to support near gale force NE winds,
which were detected by the latest scatterometer pass. Seas 6-9
ft are noted in the areas of strongest wind. Elsewhere, surface
ridging and a weak pressure gradient prevails. Fresh trades are
noted from the Turks and Caicos south to the coast of Hispaniola,
and in the Windward Passage with seas of 3-6 ft. Gentle to
moderate E to SE winds are over the western Atlantic, including
the Bahamas and areas north of Turks and Caicos. Light winds are
north of 20N between 40W and 70W excluding the area near the
Tropical Storm Henri. Gentle to moderate trades are south of 24N
in the remainder of the basin, except moderate to fresh NE winds
north of 25N east of 20W. Seas are generally 3-6 ft across the
basin, with the highest seas near Hispaniola and southeastern
Bahamas.

For the forecast west of 65W, Tropical Storm Henri will move to
30.3N 65.5W Wed morning, 30.2N 67.0W Wed afternoon, 30.2N 68.6W
Thu morning, 30.3N 70.0W Thu afternoon, 31.0N 71.1W Fri morning,
and strengthen to a hurricane near 32.0N 71.5W Fri afternoon.
Henri will change little in intensity as it moves to near 35.5N
69.6W Sat afternoon. On the forecast track, the center of Henri
should pass well to the south of Bermuda through tonight.
Elsewhere, high pressure will persist across the forecast waters
through the period.

$$
ERA
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