[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 032320
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Fri Sep 3 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...

Hurricane Larry is centered near 15.0N 42.0W at 03/2100 UTC or
1020 nm W of the Southernmost Cabo Verde Islands moving WNW at
14 kt. Estimated minimum central pressure is 978 mb. Maximum
sustained wind speed is 85 kt with gusts to 105 kt. Satellite
imagery continues to depict a somewhat asymmetrical central dense
overcast. Numerous moderate to strong convection is noted within
250 nm of the center in the southern semicircle and 200 nm in the
northern semicircle. A band of scattered moderate to isolated
strong convection is south of the system from 07N to 11N between
40W and 47W. Peak seas are 29 ft with 12 ft seas extending within
270 nm of the center in the northern semicircle, 240 nm in the SE
quadrant, and 180 nm in the SW quadrant. Larry will continue
moving WNW over the weekend and a turn to the northwest is
forecast by early next week. Additional strengthening is forecast
during the next few days, and Larry is forecast to become a major
hurricane this weekend. Please read the latest High Seas Forecast
issued by the National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has an axis along 28W from 19N
southward, moving westward at 15 kt. There is no significant
convection associated with this wave.

A tropical wave has an axis along 66W from 20N southward, moving
westward at 15-20 kt. Scattered moderate to isolated strong
convection is noted east of the wave near the Windward Islands,
from 10N to 14N between 60W to 65W. Scattered thunderstorms are
also near the wave axis across Puerto Rico.

A western Caribbean Sea tropical wave has an axis along 81W from
12N southward, moving westward at 15 kt. Scattered moderate
convection is noted within 20 nm of the wave S of 11N.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis passes through the coast of Senegal near
13N17W to 11N25W. It resumes southwest of Hurricane Larry near
11N42W to 09N48W. The ITCZ extends from 09N48W to 10N57W. Aside
from the convection associated with Hurricane Larry and the
tropical waves, numerous strong convection is moving off the
African coast from 09N to 15N E of 18W.

GULF OF MEXICO...

At 2100 UTC, stationary front was lingering across the northern
Gulf of Mexico from central Florida near 28N83W to south- central
Louisiana near 29N92W. Isolated thunderstorms are noted across the
northern and central Gulf, N of 26N and from the Florida coast to
the Upper Texas coast. Otherwise, high pressure extends across
the basin anchored by a 1014 mb high near 25N88W. Light to gentle
winds are occurring throughout the Gulf of Mexico with seas 2 to 4
ft.

For the forecast, a surface trough moving across the Yucatan
Peninsula will move into the southwest Gulf of Mexico by late late
Sat or Sun. Unfavorable upper level winds are likely to limit
significant development while the system moves NW or N over the
western Gulf of Mexico early next week. Elsewhere, a stationary
front over the north-central and northeast Gulf will gradually
dissipate through early Sun, while weak high pressure dominates
much of the remainder of the basin.

CARIBBEAN SEA...

See the tropical waves section above for details on a convectively
active tropical wave that is presently over the eastern Caribbean.

A surface trough to the west of the Gulf of Honduras is producing
scattered moderate to isolated strong convection from 15N to 21N
and W of 82W. Moderate to fresh winds are also noted in the Gulf
of Honduras. Otherwise, diurnally driven convection is occurring
across most of the Greater Antilles and reaching adjacent waters.
Moderate to fresh trades are noted across most of the Caribbean
with strong trades near the Colombia coast. Light to gentle winds
are noted in the NW and SW Caribbean.

For the forecast, Hurricane Larry is well east of the area in the
central Atlantic near 15.0N 42.0W 978 mb at 5 PM EDT moving WNW
at 14 kt. Maximum sustained winds 85 kt gusts 100 kt. Larry will
change little in intensity as it moves well northeast of the
Leeward Islands late Mon early Tue, and tropical storm force are
possible east of 60W by Sun night and Mon. At a minimum, large
swells generated by Hurricane Larry are expected to propagate
across the waters east of the Leeward Islands on Sun, likely
spreading west of 65W Mon and Mon night. Elsewhere, fresh to
occasionally strong trade winds will pulse off Colombia through
late Sat.

ATLANTIC OCEAN...

Please see the Special Features section for details on Hurricane
Larry.

At 2100 UTC, a cold front extended off the Florida coast from
30N76W to 28N81W. A pre-frontal trough extends south of the front
across the northern Bahamas from 29N78W to 25N79W. Scattered
moderate convection is noted along and south of the front N of 24N
between 72W and 80W. Gentle to moderate NE winds are north of the
front with gentle SW winds ahead of the front. Seas range 3 to 6
ft.

Towards the central Atlantic, an upper-level low is centered near
25N66W. This is bringing an area of scattered moderate to
isolated strong convection from 22N to 31N between 64W to 73W.
Another area of numerous strong convection is to the east of the
upper low from 23N to 28N between 55W to 62W. Otherwise, high
pressure extends across the central and eastern Atlantic anchored
by a 1021 mb high near 30N48W. Light to gentle winds are generally
occurring in this area with seas 3 to 5 ft.

For the forecast east of 65W, Hurricane Larry is well east of the
area in the central Atlantic near 15.0N 42.0W 978 mb at 5 PM EDT
moving WNW at 14 kt. Maximum sustained winds 85 kt gusts 100 kt.
Larry will continue to move WNW through Sun, and will pass well
northeast of the Leeward Islands near 19.4N 50.8W Sun afternoon,
20.7N 52.8W Mon morning, and 21.9N 54.5W Mon afternoon. Larry will
change little in intensity as it moves more NW thereafter well to
the north of Leeward Islands. Large swells generated by Hurricane
Larry are expected to propagate across the waters east of the
Leeward Islands on Sun, likely spreading west of 65W Mon and Mon
night.

In the eastern Atlantic, a trough extends to the west of the
Canary Islands from 31N22W to 25N28W. Showers are noted along this
trough. Otherwise, high pressure extends across the area. Mostly
gentle to moderate winds are noted in this region with seas 4 to 7
ft.

$$
AReinhart
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