[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081805
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT Tue Sep 8 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
1745 UTC.


...SPECIAL FEATURES...

Tropical Storm Paulette is centered near 18.4N 43.3W at 08/1500
UTC or about 1120 nm west of the Cabo Verde Islands or 1125 nm
east of the northern Leeward Islands moving northwest at 5 kt.
Estimated minimum central pressure has lowered to 995 mb. Maximum
sustained wind speed has increased to 55 kt with gusts to 65 kt.
Satellite imagery shows increasing scattered moderate to
isolated strong convection within 60 nm of the center, except 30
nm in the SE quadrant. Similar convection denotes and outer rain
band from 18N to 21N between 40-43W, and within 30 nm of line from
15N41W to 18N39W. Paulette will continue on its current motion
through tonight before a turn toward the west-northwest or west
with a slight increase in forward speed is expected during the
next couple of days. Moderate additional strengthening is possible
today and Paulette could be near hurricane strength by tonight.
Gradual weakening is then expected by late Wed. 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 Storm Rene is centered near 16.5N 26.5W at 08/1500 UTC
or 90 nm west-northwest of the Santo Cabo Verde Islands moving
westward at 14 kt. Estimated minimum central pressure is 1001 mb.
Maximum sustained wind speed is 35 kt with gusts to 45 kt.
Satellite imagery shows that its convective bands are not
presently well-defined for the time being. The imagery depicts
scattered moderate to isolated strong convection within 90 nm of
the center in the northern semicircle and within 60 nm of the
center in the southern semicircle. An outer broken convective
rain band consists of mainly moderate convection and is within
30 nm of a line from 14N27W to 16N29W and to 18N28W. Rene will
continue on its current motion through tonight, before it acquires
an expected motion toward the west to west-northwest over the
next two or three days. On the forecast track, the center of Rene
will move away from the Cabo Verde Islands later today. Rene is
expected to produce 1 to 3 inches of rain across portions of the
Cabo Verde Islands today. Tropical storm conditions are still
occurring over the western portion of the Cabo Verde Islands.
These winds will subside later today. Little change in strength
is expected today, followed by gradual strengthening Thu. through
Fri. Rene is forecast to become a hurricane in a couple of 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 WAVES...

A central Caribbean tropical wave has its axis along 71W south of
20N. It is moving westward at 15-20 kt. Scattered showers and
isolated thunderstorms are within 180 nm west of the wave axis
from 11N to 13N. Isolated showers are within 120 nm west of
the wave axis from 13N-18N. The earlier scattered moderate to
strong convection over northern Colombia has dissipated.

A western Caribbean tropical wave has its axis along 84W south of
19N, moving westward at about 15 kt. This wave shows no
signals both at the low and mid-levels in the latest model data.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis has shifted southward since the overnight
hours as low pressure associated with a tropical wave develops
inland Africa. It is analyzed from a 1009 mb low near 12N04W to
the coast of Liberia near 06N10W and to near 06N14W, where it
beaks down. It resumes to the southwest of Paulette near 13N47W
and to 09N53W, where it transitions to the ITCZ to near 10N60W.
Scattered moderate convection is seen from 11N-13N between 43W-
48W and within 120 nm south of the trough between 08W-14W.

GULF OF MEXICO...

A weakening stationary front extends across the northern Florida
Peninsula as high pressure over the Carolinas continues to
stretch southwestward to over the central Gulf. A slow moving
westward surface trough is analyzed from near just offshore of
the Florida Gulf coast near 27N85W south-southwestward to 24N85W
and to the northern Yucatan Channel. An upper-level trough is
over the eastern Gulf. Isolated small showers and thunderstorms
are within 60 to 90 nm of this trough. Other isolated showers and
thunderstorms, moving to the northwest, are north of 25N and west
of 92W, and also over the far southern Bay of Campeche. Isolated
showers moving westward are elsewhere east of 90W. Both buoy data
and latest scatterometer data depict mainly gentle to moderate
east-southeast winds across the basin. Current altimeter data
passes and buoys reveal relatively low seas in the range of 1-3 ft
throughout the basin.

As for the forecast, the stationary front will gradually
dissipate into late part of the week. The eastern Gulf surface
trough will continue to slowly move westward through the
remainder of the week.

CARIBBEAN SEA...

A rather weak pressure pattern persists over the area as
was shown in the latest pressure analysis. An elongated upper-
level low is located over the eastern Caribbean at 16N65W, with a
trough extending southwestward to near 13N67W. Upper-level ridging
exists between this trough and weak upper- level trough over the
western Caribbean that extends from western Cuba to 18N84W and to
the northeast coast of Honduras. The eastern periphery of upper-
level ridging is present west of this trough. Atmospheric
instability initiated mainly by the upper-level low near 16N65W
has resulted in scattered showers and thunderstorm to be north of
16N and east of 64W and to over the Leeward Islands and
surrounding waters. Similar activity is over Puerto Rico and
waters that include those surrounding the U.S. and British Virgin
Islands. Scattered moderate to isolated strong convection aided by
the eastern extension of the eastern Pacific monsoon trough is
seen from 09N to 12N between 76W and 79W. Isolated showers and
thunderstorms are elsewhere south of 20N and west of 76W.

The tropical wave along 71W will continue westward through the
central Caribbean through Wed, then across the western Caribbean
during late in week. Latest scatterometer data showed gentle
to moderate trades throughout the basin. Little change in marine
conditions is anticipated through the next several days.

ATLANTIC OCEAN...

Refer to the Special Features section above for details on
both Tropical Storm Paulette and on Tropical Storm Rene.

A weakening stationary front is analyzed over northern Florida.
It extends northeastward to offshore of the Carolinas. Scattered
moderate convection is noted within 180 nm SE of the front. A 1012
mb low pressure area is near 30N68W along a trough axis N of 26N.
Scattered moderate to isolated strong convection is increasing
within 90 nm of the low in the SW quadrant. Similar convection is
noted from 25N-28N between 66W-69W. The low pressure has a low
chance of tropical formation through the next 48 hours as it
drifts westward well to the north and northeast of the Bahamas
during the rest of the week. Scattered moderate convection is
noted From 22N- 26N from across the Bahamas to offshore of the
Florida coast. This convection is mainly being triggered by very
moist southerly flow that is present to the east of a mid to
upper-level trough over the eastern Gulf of Mexico. Additional
scattered moderate convection is occurring from 24N-30N between
55W-60W associated with an upper-level low near 27N59W and
related trough that extends from it northwestward to near 32N65W.

As for the forecast, the stationary front off the northeast
Florida coast will dissipate tonight. Large swells associated
with Paulette may spread into the waters E of the Bahamas by the
end of the week into the weekend. Otherwise, mainly gentle to
moderate flow will prevail across the basin through the week.

$$
Aguirre
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