[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121815
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Sep 12 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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

Newly formed Tropical Storm Nicholas is centered near 20.5N 94.8W
at 12/1500 UTC or 115 nm NE of Veracruz Mexico, and moving NNW at
11 kt. Estimated minimum central pressure is 1008 mb. Maximum
sustained winds are 35 kt with gusts to 45 kt. Seas are peaking at
8 to 10 ft near the center. Numerous moderate to strong
convection is present near and N of the center from 19N to 24N
between 92W and 97W. Nicholas is expected to continue on a NNW
track through tonight, then slowly turn toward the N or NNE late
Monday. This will bring Nicholas very close to the coast of NE
Mexico and S Texas late Monday, before approaching S or central
Texas Monday night or early Tuesday. Nicholas is forecast to
gradually strengthen over the couple of days. Rainfall of 3 to 5
inches are possible near the Mexico-Texas border, and 6 to 10
inches from Corpus Christi northeastward through Houston to Lake
Charles. This will increase the chance of flooding at urban and
low-lying areas, and near rivers and streams.

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 website -
www.nhc.noaa.gov/graphics_at4.shtml?start#contents

...TROPICAL WAVES...

An Atlantic tropical wave is along 27W from 21N southward and
moving W at 15 to 20 kt. Scattered moderate convection is noted
from 06N to 10N between 23W and 31W.

Another Atlantic tropical wave is near 49W from 22N southward and
moving W near 15 kt. Much drier air at mid levels are hindering
any significant convection near this wave.

A Caribbean tropical wave is along 69W from 21N southward across
the E Dominican Republic to NW Venezuela, and moving W at 15 to
20 kt. Enhanced by an upper-level low N of the Dominican Republic
near 21N69W, scattered showers and isolated thunderstorms are
occurring over the E Dominican Republic and N central Caribbean
Basin.

A former Caribbean tropical wave is now over the E parts of
Honduras and Nicaragua across Costa Rica into the E Pacific, and
moving W at 10 to 15 kt. Scattered showers and isolated
thunderstorms are evident over central and S Nicaragua.

...MONSOON TROUGH/ITCZ...

A monsoon trough passes through the Gambia coast near 13N16W
through a 1010 mb low near the Cabo Verde Islands at 17N25W to
13N35W. The ITCZ is seen farther SW from 06N37W to 06N47W.
Scattered moderate convection is found near and NE of the low from
17N to 22N between 20W and 26W, and near the monsoon trough from
05N to 15N between the African coast and 18W. Scattered showers
and a few thunderstorms are present near the ITCZ from 05N to 08N
between 37W and 42W. The National Hurricane Center is monitoring
this low and it has a low chance of development over the next 48
hours.

The eastern end of the E Pacific monsoon trough is triggering
scattered showers and isolated thunderstorms across Panama and the
SW Caribbean Basin.

...GULF OF MEXICO...

Refer to the Special Features section above for details on newly
developed Tropical Storm Nicholas over the SW Gulf.

A surface trough curves northeastward across the NW Gulf from
25N96W to just S of the Louisiana coast at 29N93W. Scattered
showers and isolated thunderstorms are noted N of 24N between 88W
and Mexico-Texas coast. Moderate to fresh SE winds and seas at 4
to 6 ft are seen across the area. Convergent ESE trades are
causing similar conditions near the Florida Keys, including the
Straits of Florida. Fresh to strong SE winds and seas of 6 to 8 ft
are evident over the central and S central Gulf. Gentle to
moderate ESE winds and seas at 2 to 4 ft prevail for the rest of
the Gulf.

For the forecast, Tropical Storm Nicholas is near 20.5N 94.8W
1008 mb at 15 UTC and moving NNW at 11 kt. Maximum sustained
winds are 35 kt with gusts to 45 kt. Nicholas will move to 21.9N
95.7W this evening, 24.1N 96.6W Mon morning, 26.4N 96.9W Mon
evening, 28.2N 96.5W Tue morning, inland to 29.4N 95.9W Tue
evening, and move inland and weaken to a tropical depression near
30.3N 95.2W Wed morning. Nicholas will move inland near 31.0N
94.8W by early Thu.

...CARIBBEAN SEA...

Please see the Tropical Waves and Monsoon Trough/ITCZ sections
above for convection in the Caribbean Basin. Moderate to fresh
trades and sea of 4 to 6 ft are found over the W and central
basin. Mainly gentle trades and seas at 3 to 5 ft prevail for the
rest of the basin.

For the forecast, the fresh to strong winds in the Gulf of
Honduras will pulse this evening. By tonight and into Mon
morning, moderate to locally fresh trades will prevail across the
basin through Thu.

...ATLANTIC OCEAN...

A surface trough E of the Windward Islands near 15N58W is coupling
with divergent flow aloft to produce numerous moderate to isolated
strong convection from 13N to 16N between 55W and the Windward
Islands. An upper-level low N of the Dominican Republic
near 21N69W is triggering scattered showers and thunderstorms N of
Puerto Rico and Leeward Islands from 19N to 26N between 59W and
71W. A stationary front extends westward from 30N70W to just off
the N Florida coast. Scattered showers and isolated thunderstorms
are noted N of 28N between 72W and the N Florida coast. Refer to
the Tropical Waves and Monsoon Trough/ITCZ sections above for
additional convection across the Atlantic Basin.

An elongated 1030 mb high near 36N45W continue to dominate the NW
central Atlantic with light to gentle winds and seas at 3 to 5 ft
N of 24N between 31W and the Georgia-Florida coast. Gentle to
moderate with locally fresh NW to SW winds and seas of 6 to 8 ft
are present N of 27N between 18W and 31W. Gentle to moderate
trades and seas at 4 to 6 ft are evident between 12N and 24N
between 26W and the Lesser Antilles. Light to gentle winds and
seas of 4 to 5 ft prevail across the remainder of the Atlantic
Basin.

For the forecast west of 60W, a frontal boundary will linger
across the area through Mon which will bring showers and
thunderstorms across the area. Otherwise, quiescent conditions
will prevail through Wednesday. Meanwhile, an area of low pressure
is expected to form north of the southeastern Bahamas in a few
days resulting from the northern end of a tropical wave
interacting with an upper-level trough. Gradual development of
this system is possible, and a tropical depression could form by
the middle of the week several hundred miles southeast of the
Carolinas while it moves northwestward across the western
Atlantic. This system has a low chance of formation in the next 48
hours and a medium chance through the next 5 days.

$$

Chan
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