[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131731
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Sun Sep 13 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
1700 UTC.

...SPECIAL FEATURES...

...T.S. SALLY...

Tropical Storm Sally is centered near 27.5N 84.9W at 13/1500 UTC
or 115 nm W of St. Petersburg Florida moving WNW at 10 kt.
Estimated minimum central pressure is 998 mb. Maximum sustained
wind speed is 50 kt with gusts to 60 kt. Numerous moderate
scattered strong convection is noted within 120 nm of the center
in the NE quadrant and 210 nm SE quad. Scattered moderate
isolated strong convection is elsewhere within 150 nm NE quad
and 240 nm SE quad. The center of Sally will move over the
north-central Gulf of Mexico tonight and Monday, then turn to
the north-northwest Monday night as it approaches the north-
central Gulf Coast within the Hurricane Warning area. Sally is
expected to move farther inland over southeastern Louisiana
Tuesday and Tuesday night. Further strengthening is expected over
the next day or so, and Sally is forecast to become a hurricane
on Monday, with some additional strengthening possible before
landfall Monday night. A dangerous storm surge is expected for
coastal portions of southeastern Louisiana and Mississippi,
where a Storm Surge Warning is in effect. Sally is expected to be
a slow moving system resulting in significant flash flooding due
to very heavy rainfall for the central Gulf Coast Monday through
the middle of the week. 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.

...HURRICANE PAULETTE...

Hurricane Paulette is centered near 29.9N 61.9W at 13/1500 UTC or
210 nm SE of Bermuda moving NW at 12 kt. Estimated minimum
central pressure is 976 mb. Maximum sustained wind speed is 70
kt
with gusts to 85 kt. Scattered moderate isolated strong
convection is noted within 150 nm of the center in the northern
semicircle and SW quadrant, and within 60 nm SE quad. The center
of Paulette will move near or over Bermuda Monday morning.
Strengthening is forecast, and Paulette is expected to be a
dangerous hurricane when it approaches Bermuda late tonight and
early Monday. Some further strengthening is possible when
Paulette turns northeastward and moves away from Bermuda late
Monday through Tuesday. 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.

...T.D. RENE...

Tropical Depression Rene is centered near 26.8N 47.6W at 13/1500
UTC or 1000 nm NE of the northern Leeward Islands moving NW at
8 kt. Estimated minimum central pressure is 1011 mb. Maximum
sustained wind speed is 25 kt with gusts to 35 kt. Isolated
moderate to strong convection is noted within 120 nm of the
center in the eastern semicircle. Rene is forecast to continue
weakening and become a remnant low on Monday. 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.

...T.D. TWENTY...

Tropical Depression Twenty is centered near 12.3N 36.4W at
13/1500 UTC or 755 nm WSW of the Cabo Verde Islands moving WNW at
9 kt. Estimated minimum central pressure is 1006 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Scattered
moderate isolated strong convection extends out 270 nm from the
center in the southern semicircle and 180 nm NW quadrant. A
motion to the west or west-northwest is expected to continue
through Tuesday, followed by a turn to the northwest Tuesday
night or Wednesday. Strengthening is expected, and the system is
forecast to become a hurricane on Tuesday. 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.

...EASTERN ATLANTIC LOW PRESSURE...

A 1009 mb low along a tropical wave is located near 17N27W, or
about 100 nm west of the westernmost Cabo Verde Islands. The
low is moving to the WNW at 10 kt. Scattered moderate
convection is from 13N-20N between 23W-31W. Although the low's
circulation appears somewhat elongated, the associated shower
and thunderstorm activity is showing some signs of organization.
Environmental conditions are expected to be conducive for
additional development during the next day or so while the system
moves toward the NNW at 5 to 10 kt, and a tropical depression is
likely to form before it moves over colder waters and into an
area of strong upper-level winds by Tuesday. This system has a
high chance of tropical cyclone formation during the next 48
hours. Please refer to the latest Tropical Weather Outlook at
www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2 for more
details.

...TROPICAL WAVES...

A tropical wave along 27W is discussed in the Special Features
section above.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 16N17W
to a 1009 mb low near 17N27W to 15N32W. The monsoon trough
continues from 10N40W to 09N43W to 11N49W. Aside from the
convection mentioned above in the Special Features section,
scattered moderate isolated strong convection is from 06N-13N
between 40W-46W.

GULF OF MEXICO...

Tropical Storm Sally, located over the eastern Gulf of Mexico, is
currently producing seas to 14 ft near its center. Peak seas
associated with Sally are forecast to increase to near 24 ft by
Monday morning as it strengthens to a hurricane over the north
central Gulf of Mexico. Please see the Special Features section
above for more details on Tropical Storm Sally.

Elsewhere, a 1008 mb low near 25N93W is along a surface trough
that extends from 27N95W to 22N89W. Scattered showers and tstorms
cover much of the western Gulf of Mexico west of 92W. A recent
ASCAT pass shows moderate winds across the western half of the
Gulf of Mexico, with fresh NE winds north of 28N near the coast
of Louisiana.

Tropical Storm Sally is forecast to strengthen to a hurricane
near 28.5N 88W Mon morning, then move inland to near 30N90W Tue
morning and weaken to a tropical storm near 30.3N 90.5W Tue
evening. Sally will be near 31.5N 90W Wed morning, then
weaken to a tropical depression over Mississippi early Thu.
Elsewhere, the surface trough over the western Gulf of Mexico
will move southwest through mid-week, with a low chance of
tropical cyclone formation.

CARIBBEAN SEA...

Scattered showers and tstorms seen over western Cuba are more
due to the daytime heating than to Tropical Storm Sally, which
is located well north of the basin over the northeastern Gulf
of Mexico. The east Pacific monsoon trough is producing
scattered strong convection over the SW Caribbean south of 14N.
This convection is being enhanced by an upper-level low over
the SW Caribbean. A recent ASCAT pass shows gentle to moderate
trade winds across the basin.

Moderate trade winds will prevail in the central and eastern
Caribbean through late Tue. Surface ridging will establish over
the SW Atlantic waters by mid-week, resulting in moderate to
fresh trades in the central and eastern Caribbean. Moderate
southeast winds are expected to continue in the NW basin
through Tue. No tropical cyclones are expected over the
Caribbean Sea during the next 5 days.

ATLANTIC OCEAN...

Please see the Special Features section above for more details on
Hurricane Paulette, Tropical Depression Rene, Tropical Depression
Twenty, and the 1009 mb low west of the Cabo Verde Islands.

Scattered gusty showers and tstorms are currently seen within 60
nm of the east coasts of Florida and Georgia. This activity is
associated with the outermost rains of Tropical Storm Sally,
which is located over the eastern Gulf of Mexico. The circulation
of Sally is still producing fresh SE winds offshore of Florida,
as shown by a recent ASCAT pass. Farther east, a tail of moisture
extending well southwestward from Hurricane Paulette is enhancing
scattered showers from the SW Bahamas to 27N between 66W-73W.
However, winds in that area are gentle.

Hurricane Paulette will move to near 33N65W Mon morning, 37N60W
Tue morning, and 41N49W Wed morning. Large swell associated with
Paulette will spread westward across the offshore waters and
continue to build seas early this week. Tropical Depression
Twenty will strengthen to a tropical storm near 13N38W this
evening, then strengthen to a hurricane near 14.5N 45W Tue
morning, then move to near 16N48W Wed morning and 19N51W Thu
morning.

$$
Hagen
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