[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 140603
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Sep 14 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
0500 UTC.

...SPECIAL FEATURES...

At 14/0300 UTC, Nicholas is upgraded to hurricane status. Then,
the hurricane made landfall near 1230 AM CDT (0530 UTC) on
eastern part of the Matagorda Peninsula, about 10 miles (15 km)
west-southwest of Sargent Beach, Texas. Nicholas is bringing
heavy rains, strong winds and storm surges to portions of the
central and upper Texas coasts. At 14/0600 UTC, Hurricane Nicholas
is centered near 28.8N 95.7W or 20 nm NE of Matagorda Texas
moving NNE at 9 kt. Estimated minimum central pressure is 991 mb.
Maximum sustained wind speed is 65 kt with gusts to 80 kt. Peak
seas are currently 25 ft. Numerous moderate and isolated strong
convection is noted within 120 nm N and 90 nm S semicircles. On
the forecast track, the center of Nicholas is expected to move
slowly over southeastern Texas today and tonight, and over
southwestern Louisiana on Wednesday. Weakening is expected during
the next couple of days as Nicholas moves over land. Nicholas is
expected to produce storm total rainfall of 6 to 12 inches, with
isolated maximum amounts of 18 inches, across the upper Texas
coastal areas into Wednesday. The combination of a dangerous storm
surge and the tide will cause normally dry areas near the coast
to be flooded by rising waters moving inland from the shoreline.

Please read the latest High Sea Forecast issued by the National
Hurricane Center at website -
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest
Nicholas NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

A tropical wave located just west of the African coast is
producing a large area of showers and thunderstorms that are
showing signs of organization. The tropical wave axis is along
15W with a 1010 mb low pressure near 11N15W. A large cluster of
moderate to strong convection covers the area from 10N-16N between
14W-20W.Environmental conditions are forecast to be conducive for
gradual development of this disturbance over the next several
days, and a tropical depression is likely to form by the weekend
while the system moves westward at about 15 mph across the eastern
tropical Atlantic Ocean. This system has a medium chance of
tropical cyclone formation through 48 hours. Please, see the
latest Tropical Weather Outlook at www.hurricanes.com

...TROPICAL WAVES...

A tropical wave is in the Atlantic Ocean along 38W from 17N
southward, moving W at around 15 kt. Scattered moderate convection
is noted on either side of the wave axis from 06N-13N between
37W-41W.

A tropical wave has moved into the Caribbean Sea. Its axis is
along 62W. Scattered showers with embedded thunderstorms are seen
ahead of the wave axis over the eastern Caribbean, particularly
from 12N-15N between 63W-67W. The wave combined with an upper
level low spinning over Hispaniola will support showers and
thunderstorms over Puerto Rico and Hispaniola tonight and Wed.

Another tropical wave is in the Caribbean Sea along 76W, and
extends from eastern Cuba to northern Colombia. Isolated to
scattered moderate convection is observed near the wave axis but
mainly over northern Colombia, and near Cabo Cruz, Cuba.

A tropical wave is over the Yucatan peninsula and Guatemala.
Scattered moderate convection is behind the wave axis in the
eastern Pacific region.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 11N15W to 10N30W to 08N43W. the
ITCZ continues from 08N43W to the coast of Guyana near 07N58W.
Scattered moderate convection is seen from 03N-06N between 08W-
13W. This convective activity is affecting parts of Liberia.
Similar convection is noted from 04N-07N between 21W-25W.

...GULF OF MEXICO...

Attention remains focused on recently upgraded Hurricane Nicholas.
Refer to the Special Features section above for more details.

Outside of Hurricane Nicholas, scatterometer data provide
observations of gentle to moderate E-SE winds over the eastern
half of the Gulf region, and over the SW Gulf. Seas are 3-5 in the
eastern Gulf and 4-6 ft over the SW Gulf based on an altimeter
pass. Fresh to strong winds in the outer periphery of Nicholas
dominates the NW Gulf with seas of 8-12 ft.

For the forecast, an area of fresh to strong winds will persist
today over the NW Gulf between Nicholas and high pressure over
the SE of United States. A ridge will build westward across the
Gulf waters in the wake of Nicholas producing mainly light to
moderate SE to S winds.

...CARIBBEAN SEA...

A pair of tropical waves are moving westward across the Caribbean
Sea. Please see the Tropical Waves section for more information.

Satellite derived wind data show mainly gentle to moderate trade
winds across much of the basin. Moderate to locally fresh winds
are noted in the Windward passage, Gulf of Honduras and near the
coast of Colombia. Seas are generally 2-4 ft.

For the forecast, gentle to moderate trades will prevail across
the basin today and Wed. By Wed night, moderate to fresh winds
will return in the Gulf of Honduras and the south-central
Caribbean and continue through the remainder of the forecast
period.

...ATLANTIC OCEAN...

High pressure dominates the Atlantic forecast waters with a 1021
mb high center W of Bermuda near 33N70W. Another high pressure
center of 1023 mb is located near 33N41W. A trough, reflection of
an upper-level is analyzed from 27N68W to 20N70W. Scattered
moderate convection is noted on either side of the trough covering
the waters from from 20N-27N between 61W-72W. Based on streamlines
analysis and scatterometer data another trough is W of the Cabo
Verde islands and runs from 19N28W to 12N36W. A pair of 1010 mb
lows are along the trough axis. Mainly low clouds are associated
with these features. A stationary front crosses the Canary
Islands where northerly winds have been reported.

For the forecast west of 65W, an area of low pressure is expected
to form by midweek a couple of hundred miles north of the southeastern
or central Bahamas as a tropical wave interacts with an upper-level
trough. Some gradual development of this system is possible thereafter,
and a tropical depression could form later this week while the system
moves north-northwestward or northward across the western Atlantic.

For the forecast east of 65W, see the Special Features section for
more details on the tropical wave located over the far eastern
tropical Atlantic.

$$
GR
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