[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122254
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Sep 12 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
2230 UTC.

...SPECIAL FEATURES...

Tropical Storm Sally is centered near 25.7N 81.9W at 12/2100 UTC
or 30 nm SSW of Naples Florida moving W at 6 kt. Estimated
minimum central pressure is 1004 mb. Maximum sustained wind
speed is 35 kt with gusts to 45 kt. Scattered moderate isolated
strong convection is noted within 180 nm SE semicircle. A west-
northwestward or northwestward motion is expected during the next
couple of days. The center of Sally is forecast to move over the
southeastern and eastern Gulf of Mexico tonight and Sun, and then
move over the north-central Gulf of Mexico Sun night and Mon.
Strengthening is expected over the next couple of days, and Sally
is forecast to become a hurricane on Mon.
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 Storm Paulette is centered near 28.4N 58.5W at 12/2100
UTC or 400 nm SE of Bermuda moving NW at 13 kt. Estimated
minimum central pressure is 987 mb. Maximum sustained wind speed
is 60 kt with gusts to 75 kt. Seas 12 ft or greater are within
240 nm NE quadrant, 120 nm SE quadrant, 180 nm SW quadrant, and
210 nm NW quadrant with peak seas to 28 ft. Scattered moderate
isolated strong convection is noted within 150 nm NW quadrant. A
northwestward or west-northwestward motion is expected through
Sun night, followed by a turn toward the north with a decrease in
forward speed on Mon, and a northeastward motion Mon night and
Tue. The center of Paulette will move near or over Bermuda Mon
morning. Strengthening is forecast, and Paulette is expected to
become a hurricane tonight. Paulette is expected to be a dangerous
hurricane when it is near Bermuda Sun night and Mon.
Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT2.shtml and Forecast/
Advisory at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for more
details.

Tropical Depression Rene is centered near 24.3N 45.6W at 12/2100
UTC or 1040 nm ENE of the Northern Leeward Islands moving NW at
12 kt. Estimated minimum central pressure is 1006 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Seas 12 ft or
greater are within 30 nm NW quadrant with peak seas to 13 ft.
Isolated weak convection is noted within 150 nm NW quadrant. A
slower northwestward motion is expected by Sun, and a slow
westward motion is forecast by Sun night. On Mon and Tue, the
system is forecast to turn west-southwestward. Some gradual
weakening is possible over 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 Depression Twenty is centered near 11.4N 33.5W at
12/2100 UTC or 1760 nm E of the Northern Leeward Islands moving
WNW at 8 kt. Estimated minimum central pressure is 1005 mb.
Maximum sustained wind speed is 30 kt with gusts to 40 kt.
Scattered moderate convection is noted within 240 nm W semicircle.
A west-northwestward motion is expected to continue for the next
few days with a slight increase in forward speed early next week.
Slow strengthening is expected over the next day or so, and the
depression is forecast to become a tropical storm by Sun night. A
faster rate of strengthening is possible early next week.
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.

Showers and thunderstorms located near the Cabo Verde Islands are
associated with a broad area of low pressure that has developed
along a tropical wave near 24W. Environmental conditions support
some additional development during the next few days, and a
tropical depression could form over the far eastern tropical
Atlantic early next week while the system moves slowly west-
northwestward. By mid-week, upper-level winds could become less
conducive for development. This system has a medium chance of
tropical cyclone formation during the next 48 hours.

...TROPICAL WAVES...

An eastern Atlantic tropical wave axis is along 24W, moving W at
10-15 kt. Scattered moderate isolated strong convection is noted
from 15N to 18N between 24W and 28W. Please see the Special
Features section above for more details.

A tropical wave axis associated with Tropical Depression Twenty
is along 33.5W, moving W at 10-15 kt. Please see the Special
Features section above for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Mauritania near
18N16W to 12N30W to 10N43W. Besides the convection described
above, isolated moderate convection is noted within 240 nm of the
monsoon trough W of 24W.

GULF OF MEXICO...

Please see the Special Features section above for more details on
Tropical Storm Sally.

A dissipating stationary front is analyzed across the western Gulf
this evening, with some isolated showers and thunderstorms noted
near the boundary. Earlier scatterometer data showed moderate to
fresh NW winds in the SW Gulf near the coast of Veracruz. Moderate
to fresh easterly winds are occurring over the NE Gulf. Seas are
4-6 ft in this region based on recent buoy observations.

Elsewhere, a trough extends across the north-central Gulf from
28N94W to 24N89W. Some slow development of this system is possible
while it moves westward and then southwestward over the northern
and western Gulf through the middle of next week. This system has
a low chance of tropical cyclone formation.

Tropical Storm Sally will move to 26.4N 83.4W Sun morning, 27.3N
85.3W Sun afternoon, 28.0N 86.9W Mon morning, then strengthen to
a hurricane near 28.5N 88.1W Mon afternoon. Hurricane Sally will
be near 29.0N 89.0W Tue morning and 29.7N 89.3W Tue afternoon.
Sally will weaken to a tropical storm while moving inland over
Louisiana and Mississippi Wed afternoon. Elsewhere, a surface
trough over the north central Gulf will move west and southwest
over the northern and western Gulf of Mexico through the middle of
next week. This trough has a low chance of tropical formation.

CARIBBEAN SEA...

A weak pressure gradient over the basin is supporting light to
gentle winds across the region, with some moderate trades noted
near the northern coast of Colombia. Swell from distant Tropical
Storm Paulette continues impacting the Atlantic and Caribbean
passages. Otherwise, seas are 2-4 ft in the south-central waters,
and 3 ft or less elsewhere.

Tropical Storm Paulette will continue to move north away from the
area, but large swell associated with Paulette will affect the
Atlantic and Caribbean Passages this weekend. Rene has weakened to
a tropical depression this morning well east of the area.
Tropical Depression Rene is not expected to strengthen, but could
approach areas north and east of the Leeward Islands toward the
middle of next week.

ATLANTIC OCEAN...

Please see the Special Features section above for more details on
Tropical Storm Paulette, Tropical Depression Rene, and Tropical
Depression Twenty.

Outside of the tropical systems, light to gentle winds prevail
across the Atlantic waters S of 20N and W of 35W. Seas in this
area are generally 4-7 ft. Some isolated showers and thunderstorms
are ongoing east of the Windward Islands, from 11N to 14N between
55W and 60W. Elsewhere, swell associated with Paulette has spread
across much of the region W of 50W, with seas 8 ft or greater in
the offshore waters as far as 70W.

Tropical Storm Paulette will strengthen to a hurricane near 29.2N
60.4W Sun morning and move to 30.3N 62.8W Sun afternoon.
Hurricane Paulette should be near31.8N 64.6W Mon morning, 33.5N
64.9W Mon afternoon, 35.3N 63.2W Tue morning, and 37.0N 59.8W Tue
afternoon. Large swell associated with Paulette will spread
westward across the offshore waters and continue to build seas
this weekend into early next week. Tropical Depression Rene is not
expected to strengthen, but could approach areas north and east
of the Leeward Islands toward the middle of next week. Newly
formed Tropical Depression Twenty may approach the Tropical N
Atlantic offshore waters toward the end of next week.

$$
B Reinhart
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