[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222316
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
416 PM PDT Sat Aug 22 2020

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 32N. 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 Laura is centered near 18.0N 68.1W at 22/2100 UTC
or 90 nm W of Ponce Puerto Rico moving W at 16 kt. Estimated
minimum central pressure is 1004 mb. Maximum sustained wind
speed is 45 kt with gusts to 55 kt. Laura is moving toward
Dominican Republic while continues to produce heavy rain over
Puerto Rico. Numerous moderate scattered strong convection is
noted from 15N-18N between 65W-68W. Clusters of moderate to
strong convection are already affecting parts of Dominican
Republic. On the forecast track, the center of Laura will move
away from Puerto Rico this evening, near or over Hispaniola
tonight, near or over Cuba Sunday and Monday, and into the
southeastern Gulf of Mexico Monday night and Tuesday. No
significant changes in strength are forecast during the next 48
hours while Laura moves near or over Hispaniola and Cuba. Some
strengthening is forecast once Laura moves into the Gulf of Mexico
Monday night and Tuesday. Heavy rain across Puerto Rico,
Hispaniola and Cuba could lead to life- threatening flash
flooding. Swells generated by Laura are affecting portions of the
northern Leeward Islands. These swells are expected to spread
across the northern coasts of Puerto Rico, Hispaniola, Cuba, much
of the Bahamas, and the Florida Keys during the next few days.

Please read the latest NHC Public
Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and
Forecast/ Advisory at
https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more details.

Tropical Storm Marco is centered near 21.9N 85.7W at 22/2100 UTC
or 40 nm W of the western tip of Cuba moving NNW at 11 kt.
Estimated minimum central pressure is 992 mb. Maximum sustained
wind speed is 55 kt with gusts to 65 kt. A band of moderate to
scattered strong convection is within about 90 nm E of the
center. This convective activity has been affecting western Cuba
during the last several hours producing heavy rain. Marco is
expected to continue moving toward the north-northwest across the
central Gulf of Mexico on Sunday and is forecast to reach the
northern Gulf coast on Monday. After moving inland, Marco is
expected to slow down and turn toward the northwest and west-
northwest Monday night and Tuesday, moving across southern
Louisiana into east Texas. Strengthening is forecast during the
next day or two, and Marco is expected to become a hurricane
tonight or on Sunday. Marco is likely to still be at or near
hurricane strength when it reaches the northern Gulf coast on
Monday. Weakening is forecast to occur while the center moves
farther inland Monday night and Tuesday.

Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for
more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is W of the Cabo Verde Islands
along 28W from 21N southward, moving W at 10-15 kt. Convection is
limited near the wave axis. As a result, tropical cyclone
development is no longer expected to occur as environmental
conditions are forecast to be unfavorable as the system moves
westward over the tropical Atlantic.

An eastern Caribbean tropical wave has an axis along 67W from
14N southward, moving W at 10 kt. The wave appears to induce
some convective activity over Venezuela.

A central Caribbean tropical wave has an axis along 76W from 18N
southward, moving W at 15 kt. Isolated moderate convection is
within 90 nm either side of the wave axis.

A western Caribbean tropical is along 88W from 17N southward,
extending from the SW Gulf of Honduras southward to the east
Pacific. This tropical wave spawned T.D. Fourteen in the western
Caribbean, and now has the potential to help the development of a
another tropical cyclone south of the Gulf of Tehuantepec, in the
eastern Pacific region early next week. The wave is moving W at
10 kt, and is helping to induce scattered showers and
thunderstorms over northern Central America.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Mauritania near
19N16W to 12N28W to 09N45W. The ITCZ continues from 09N45W to
08N58W. Only a cluster of moderate convection is seen from 08N-
11N between 55W-57W.

GULF OF MEXICO...

Two tropical cyclones are forecast to move across the Gulf of
Mexico between now and Wed, and both are expected to reach
hurricane strength. Please see the Special Features section
above for more details on Tropical Storm Marco and Tropical Storm
Laura.

Tropical Storm Marco is currently spreading strong winds across
the Yucatan Channel and heavy rain over the southern Gulf of
Mexico, south of 25N between 82W-87W.

Elsewhere in the Gulf currently, mid-level southerly winds are
advecting moisture from Tropical Storm Marco toward the NE Gulf
of Mexico, where scattered showers and isolated tstorms are seen,
between the Florida peninsula and 90W. A recent ASCAT pass shows
strong E to SE winds over the southeast Gulf. Gentle winds and
drier weather prevail over most of the western Gulf, west of 90W.

CARIBBEAN SEA...

Please see the Special Features section for details on Tropical
Storm Laura and Tropical Storm Marco.

Outside of Laura and Marco, some tropical waves are moving across
the basin, producing scattered showers. See the Tropical Waves
section above for details.

ATLANTIC OCEAN...

Please see the Special Features section for details on Tropical
Storm Laura.

A surface ridge dominates the remainder of the Atlantic forecast
waters, including the Bahamas and Florida. A pair of 1020 mb
centers are noted near 28N55W and near 29N69W. An area of
scattered showers related to an upper-level trough is seen from
23N-30N between 51W-58W. A surface trough is analyzed from 26N41W
to 16N43W. Mainly low clouds are near the trough axis.

$$
GR
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