[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221802
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT 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 1200 UTC surface analysis and satellite imagery through
1730 UTC.

...SPECIAL FEATURES...

Tropical Storm Laura is centered near 17.9N 67.5W at 22/1800 UTC
or about 50 nm SW of Ponce, Puerto Rico moving W at 16 kt.
Minimum central pressure is 1004 mb. Maximum sustained winds are
near 45 kt with gusts to 55 kt. Numerous moderate scattered
strong convection is within 150 nm in the NE quadrant, 180 nm
SE quad and 120 nm SW quad, including over the Virgin Islands
and portions of Puerto Rico. Scattered moderate convection is
elsewhere within 210 nm eastern semicircle, 150 nm SW quad and 90
nm NW quad. Seas are 12 feet or greater within 90 nm in the NE
quadrant, 30 nm SE quad and 30 nm NW quad. On the forecast track,
the center of Laura will move near or over Hispaniola this
afternoon and tonight, and near or over eastern Cuba Sun and Sun
night. Heavy rain across the Virgin Islands, Puerto Rico,
Hispaniola and Cuba could lead to life-threatening flash
flooding. 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 21.4N 85.5W at 22/1800 UTC
or about 45 nm SW of the western tip of Cuba moving NNW at 10
kt. Estimated minimum central pressure based on dropsonde data is
992 mb. Maximum sustained wind speed has increased to 55 kt with
gusts to 65 kt. Numerous moderate scattered strong convection is
within 120 nm of the center, except only within 60 nm in the SW
quadrant. Scattered moderate convection is elsewhere within 210
nm NE quad, 165 nm SE quad, 120 nm SW quad and 150 nm quad,
including over western Cuba. Seas are 12 feet or greater within
30 nm of the center in the NE and SW quadrants. The center of
Marco is forecast to move through the Yucatan channel this
afternoon and evening while strengthening to a hurricane. Marco
is forecast to reach the north-central Gulf of Mexico early
Monday as a hurricane, followed by a WNW bend toward the NW Gulf
of Mexico coast along with some weakening. 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 has an axis along 26W from 21N
southward, moving W at 10-15 kt. Isolated showers are near the
wave axis from 16N-21N and from 03N-10N. This system has a low
chance of becoming a tropical cyclone during the next 48 hr
before environmental conditions become unfavorable for
development.

An eastern Caribbean tropical wave has an axis along 65W from 14N
southward, moving W at 10 kt. Isolated showers are near the wave
axis.

A central Caribbean tropical wave has an axis along 75W 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 wave has an axis along 87W from 17N
southward, extending from the SW Gulf of Honduras southward to
the east Pacific. The tropical wave is moving W at 10 kt.
Scattered moderate to isolated strong convection is seen along
the Pacific coast of El Salvador and Guatemala, where heavy rain
could lead to flash flooding through early next week.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Mauritania near
19N16W to 12N26W to 08N45W. The ITCZ continues from 08N45W to
07N58W. Little to no significant convection is seen in
association with the monsoon trough or ITCZ at this time.

GULF OF MEXICO...

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 83W-87W. The center of Macro will
pass through the Yucatan Channel later this afternoon. Marco is
forecast to strengthen to a hurricane as it enters the southern
Gulf this evening. Please see the Special Features section above
for more details on Tropical Storm Marco.

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.

Tropical Storm Laura, currently located over the Caribbean Sea
near the SW tip of Puerto Rico, will move WNW over Cuba late Sun
and early Mon, and emerge into the SE Gulf of Mexico late Mon.
Laura is then forecast to strengthen to a hurricane as it moves
into the central Gulf of Mexico Tue and then moves to the U.S.
northern Gulf Coast Wed. See special features section above for
more on Laura.

CARIBBEAN SEA...

Tropical Storm Marco is producing tropical storm force winds near
the Yucatan Channel. According to a recent ASCAT pass from
22/1454 UTC, winds in excess of 25 kt associated with Marco are
confined to areas north of 18N between 82W-86W. Convection
associated with Marco is located north of 18N between 83W-87W.
The center of Marco will move through the Yucatan Channel and
into the southern Gulf of Mexico later this afternoon and into
this evening. For more information on Marco, see the Special
Features section above.

Tropical Storm Laura, centered near the SW tip of Puerto Rico,
is spreading tropical storm force winds and heavy squalls across
portions of the NE Caribbean Sea. Winds in excess of 25 kt are
occurring north of 15.5N and west of 62W according to a morning
ASCAT pass, and are confined to the eastern semicircle of Laura.
Convection associated with Laura is over the NE Caribbean north
of 14N between 62W-68.5W. For more information on Laura, see
the Special Features section above.

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...

Tropical Storm Laura, currently centered near the SW tip of
Puerto Rico, is producing tropical storm force winds and
heavy squalls over the Atlantic waters to the north of the
Virgin Islands and Puerto Rico. An ASCAT pass from 22/1340 UTC
showed that winds in excess of 25 kt associated with Laura
were confined to areas south of 23N between 62W-67.5W. For
more information on Laura, see the Special Features section
above.

A surface ridge extends from a 1024 mb high near 35N30W to a 1020
mb high near 29N52W to a 1018 mb high near 29N69W to near
Jacksonville Florida. An area of scattered showers related to an
upper-level trough is seen from 28N-32N between 53W-59W. A
surface trough from 09N51W to 15N57W is producing scattered
moderate convection from 08N-10N between 51W-54W.

$$
Hagen
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