[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172338
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Sep 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
2300 UTC.

...SPECIAL FEATURES...

Tropical Storm Odette is centered near 36.7N 71.8W at 17/2100
UTC or 200 nm SE of Cape May New Jersey moving NE at 13 kt.
Estimated minimum central pressure is 1010 mb. Maximum sustained
wind speed is 35 kt with gusts to 45 kt. Peak seas are near 13
ft. Numerous moderate and scattered strong convection is noted
from 35N-40N between 65W- 70W. Odette is expected ton continue
moving toward the northeast tonight. A turn toward the east-
northeast with an increase in forward speed is expected to begin
on Saturday and continue through Monday. On the forecast track,
the center of Odette will move away from the U.S. Mid-Atlantic
coast and pass south of Atlantic Canada over the weekend.
Strengthening is forecast during the next couple of days, and
Odette is expected to become a strong post-tropical low by
Saturday night. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT5.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml for
more details.

A tropical wave located midway between the Lesser Antilles and
Cabo Verde Islands has an axis that extends from 20N47W to a
1011 mb low pressure near 13N45W to 03N45W, moving W at 15-20
kt. Scattered moderate and isolated strong convection is noted from
12N-17N between 45W-50W. Environmental conditions are expected
to be conducive for further development during the next couple of
days, and a tropical depression is likely to form over the weekend
or early next week while moving toward the west-northwest at about
15 mph across the central tropical Atlantic and then near the
northern Leeward Islands by Monday and Tuesday.  Upper-level winds
could become less conducive for development over the southwestern
Atlantic by the early to middle part of next week.  Interests in
the Leeward Islands should monitor the progress of this system
during the next few days. The system has a high chance of
formation within the next 48 hours. Refer to the latest NHC
Tropical Weather Outlook at www.hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave is along 23W from 19N southward, moving W at 15
kt. A broad 1010 mb low pressure is along the wave near 11N22W.
Scattered moderate and isolated strong convection is found from
03N-13N between 20W-30W. This system is expected to
move toward the west and then northwest at 5 to 10 mph over the far
eastern Atlantic, and some gradual development is possible over the
weekend before upper-level winds increase and the low moves over
cooler waters. This system has a low chance of tropical cyclone
formation within the next 48 hr. Refer to the latest NHC Tropical
Weather Outlook at www.hurricanes.gov for more details.

A tropical wave is along 45W. See the Special Features section
for details.

A western Caribbean tropical wave is near 84W from 18N southward
to Honduras and Nicaragua, moving W near 15 kt. Scattered
moderate is found south of 15N west of 80W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends across the coast of Mauritania near
17N16W to 1010 mb low pressure near 11N22W to 12N42W. The ITCZ
is from 06N46W to 05N52W. Aside from the convection mentioned in
the sections above, no other deep convection is present.

GULF OF MEXICO...

The weak 1014 mb remnant low of Nicholas is drifting northward
over NW Louisiana at 2100 UTC. A surface trough extends from the
low pressure to 30N91W to 28N95W. Another surface trough extends
from 30N87W to 29N84W. A mid to upper-level low centered over
Texas is helping to induce scattered to numerous moderate with
isolated strong convection north of 24N and east of 90W. Winds
are moderate or weaker over the Gulf. Seas are 2 to 4 ft, except
near 5 ft in the Yucatan Channel.

For the forecast, weak high pressure will extend across the
eastern and central Gulf of Mexico through early next week. This
pattern will support continued gentle winds and mostly slight
seas across the Gulf through the next several days.

CARIBBEAN SEA...

The pressure gradient from ridging north of the Caribbean to the
1010 mb Colombia low is contributing toward fresh to strong NE
trades over the south-central Caribbean with moderate to fresh
trades elsewhere. Seas are 6-8 ft in the south-central Caribbean
and 4-6 ft elsewhere. Convection associated with a tropical wave
reaching Central America is described above in the Tropical
Waves section. No additional deep convection is present over the
Caribbean.

For the forecast, the Atlantic ridge will shift westward through
Sun, as newly formed Tropical Storm Odette, off the middle
Atlantic coast, lifts northward. This will support fresh to
strong winds over the south-central Caribbean and Gulf of
Honduras into early Sun. The ridge will weaken starting Sun night
as a tropical wave and area of low pressure currently across the
central Atlantic move to the northeast of the Leeward Islands
early Mon, then begin to move more NW. There is a high chance
this low pressure will form into a tropical cyclone over the next
several days. Regardless of further development, expect increase
winds, seas and thunderstorms north through east of the Leewards
early next week.

ATLANTIC OCEAN...

Please see the Special Features and Tropical Wave section above
for details on two tropical waves over the Atlantic.

An expansive ridge extends ENE-WSW north of our waters along
35N-40N. A moderate pressure-gradient between the ridge and
lower pressures in the monsoon trough/ITCZ is contributing toward
generally moderate to fresh NE to E trades across the tropical N
Atlantic. Seas are 7-9 ft from 10N-25N east of 47W and 4-6 ft
elsewhere. An upper-level trough is helping to force two surface
troughs: one from 25N54W northward to beyond 31N53W and another
from 20N48W to 27N48W. Scattered moderate convection is present
from 25N-31N between 47W-50W.

For the forecast west of 65W, weak ridging through the northern
Bahamas will support mostly light breezes and slight seas north
of 22N through early next week, and moderate trade winds and
moderate seas south of 22N at least through Sun. Meanwhile, an
area of low pressure currently well to the southeast over the
central tropical Atlantic will approach the waters northeast of
the Leeward Islands Sun and Mon then begin to move more NW over
open Atlantic waters. There is a high chance this low pressure
will form into a tropical cyclone over the next several days.
Regardless of further development, expect increase winds, seas
and thunderstorms north through east of the Leewards Islands and
Puerto Rico early next week.

$$
Landsea
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