[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141024
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1120 UTC.

...SPECIAL FEATURES...

At 14/0900 UTC, Nicholas made landfall along the Texas coast
overnight on the eastern part of the Matagorda Peninsula, about
10 miles (15 km) west-southwest of Sargent Beach, Texas. Nicholas
has been downgraded to a Tropical Storm as of 14/0900 UTC. Tropical
Storm Nicholas is centered near 29.3N 95.6W. Estimated minimum
central pressure is 994 mb. Maximum sustained wind speed is 60 kt
with gusts to 75 kt. Peak seas are currently 22 ft. Numerous
moderate and isolated strong convection is noted within 180 nm NE
and 120 nm in the SE quadrant. Scattered moderate convection is
noted along an outer band further southeast from the center north
of 25N extending W of 90W to Matamoros, Mexico. On the forecast
track, The storm should move more slowly to the northeast later
today and then eastward by Wednesday over Louisiana. Little motion
is anticipated on Thursday. Nicholas should weaken further today
and is forecast to become a tropical depression by Wednesday.
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
17W with a 1008 mb low pressure near 12N17W. A large cluster of
moderate to strong convection covers the area from 04N-17N
between 15W-23W. 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 emerged from the coast of Africa extending along
17W, south of 16N moving W at 10 to 15 kts in the Atlantic Ocean.
An area of low pressure is noted with this wave near 12N17W.
Scattered moderate to strong convection is noted on either side
of the wave axis from 04N-17N between 15W-23W.

A tropical wave is in the Atlantic Ocean along 38W from 1N
southward, moving W at around 15 kt. Scattered moderate
convection is noted on either side of the wave axis from 09N-14N
between 37W-41W.

A tropical wave over the Caribbean Sea with its axis along 62W.
Scattered showers with embedded thunderstorms are seen ahead of
the wave axis over the eastern Caribbean, particularly from
14N-18N between 60W-67W. The wave combined with an upper-level
low spinning over Hispaniola will support showers and
thunderstorms over the U.S. Virgin Islands, Puerto Rico and
Hispaniola tonight and Wed.

Another tropical wave is in the Caribbean Sea along 77W, 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.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 12N16W to 10N30W to 07N43W. The
ITCZ continues from 07N43W to the coast of Guyana near 06N58W.
Scattered moderate convection is seen south of Sierra Leone and
Liberia, and from 03N-09N between 21W-29W.

...GULF OF MEXICO...

Attention remains focused on 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 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. This pattern will 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 20N-30N between 65W-70W. Based on streamlines
analysis and scatterometer data another trough is W of the Cabo
Verde islands and runs from 21N27W to 12N3W. A 1011 mb low is
along the trough axis. Mainly low clouds are associated with these
features. A stationary front cross the Canary Islands where
northerly winds have been reported. Recent altimeter pass indicates
seas 3 to 5 ft near the Canary Islands and north of 20N E of 55W.

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.

$$
Torres
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