Issued at 800 AM CVT Mon Sep 07 2020
000
WTNT43 KNHC 071223
TCDAT3
Tropical Depression Eighteen Discussion Number 1
NWS National Hurricane Center Miami FL AL182020
800 AM CVT Mon Sep 07 2020
Shower and thunderstorm activity associated with the area of low
pressure over the far eastern Atlantic has continued to increase
and become organized in a band overnight. First light visible
satellite imagery suggests that the circulation has also become
better defined. Based on the above, advisories are being initiated
on a new tropical depression, the eighteenth of the 2020 Atlantic
hurricane seasons. Dvorak satellite estimates from both TAFB and
SAB support an intensity of 25 kt, but given the continued
improvement in organization the initial winds are set at 30 kt for
this advisory. ASCAT data later this morning should provide
additional information on the intensity of the cyclone.
The depression lies within a favorable upper-level environment and
the SHIPS guidance indicates that the vertical wind shear will
remain 10 kt or less over the next few days while the depression
traverses sea surface temperatures of around 27 degrees Celsius.
These conditions, along with a moist mid-level atmosphere should
allow for steady strengthening over the next few days, and the NHC
forecast calls for the system to become a tropical storm later
today, and a hurricane in about 72 hours. After that time, the
cyclone is forecast to pass over slightly cooler waters and the
global models depict an increase in southwesterly upper-level flow
over the system by the end of the period. These less conducive
factors are expected to slow the intensification process toward the
end of the period. The NHC intensity forecast is a blend of the
IVCN multi-model consensus and the HFIP corrected consensus.
The initial motion of the depression is a somewhat uncertain 280/10
kt. A narrow mid-level ridge to the north of the depression is
forecast to build westward over the next few days which is expected
to steer the system westward to west-northwestward, and the track
guidance is in good agreement through 72 hours. After that time, a
weakness is forecast to develop in the ridge near 40 degrees west.
and the cyclone is expected to turn west-northwestward and then
northwestward between the ridge to its northeast and Tropical
Depression Seventeen to its southwest. Since there could be some
binary interaction between the two tropical cyclones later in the
period, the longer range track guidance is not in as good of
agreement, and there is more uncertainty than average in the
long-range track forecast.
Key Messages:
1. The depression is forecast to strengthen into a tropical storm
later today and tropical storm conditions are expected to spread
over portions of the Cabo Verde Islands later today and tonight. A
Tropical Storm Warning is in effect for those islands.
2. The depression is expected to bring locally heavy rainfall to
portions of the Cabo Verde Islands through Tuesday morning.
FORECAST POSITIONS AND MAX WINDS
INIT 07/0900Z 15.2N 20.3W 30 KT 35 MPH
12H 07/1800Z 15.6N 22.0W 35 KT 40 MPH
24H 08/0600Z 16.0N 24.5W 40 KT 45 MPH
36H 08/1800Z 16.4N 27.3W 50 KT 60 MPH
48H 09/0600Z 16.8N 30.2W 55 KT 65 MPH
60H 09/1800Z 17.4N 32.9W 60 KT 70 MPH
72H 10/0600Z 18.1N 35.5W 65 KT 75 MPH
96H 11/0600Z 19.7N 39.6W 70 KT 80 MPH
120H 12/0600Z 22.4N 43.2W 70 KT 80 MPH
$$
Forecaster Brown
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000
WTNT43 KNHC 071223
TCDAT3
Tropical Depression Eighteen Discussion Number 1
NWS National Hurricane Center Miami FL AL182020
800 AM CVT Mon Sep 07 2020
Shower and thunderstorm activity associated with the area of low
pressure over the far eastern Atlantic has continued to increase
and become organized in a band overnight. First light visible
satellite imagery suggests that the circulation has also become
better defined. Based on the above, advisories are being initiated
on a new tropical depression, the eighteenth of the 2020 Atlantic
hurricane seasons. Dvorak satellite estimates from both TAFB and
SAB support an intensity of 25 kt, but given the continued
improvement in organization the initial winds are set at 30 kt for
this advisory. ASCAT data later this morning should provide
additional information on the intensity of the cyclone.
The depression lies within a favorable upper-level environment and
the SHIPS guidance indicates that the vertical wind shear will
remain 10 kt or less over the next few days while the depression
traverses sea surface temperatures of around 27 degrees Celsius.
These conditions, along with a moist mid-level atmosphere should
allow for steady strengthening over the next few days, and the NHC
forecast calls for the system to become a tropical storm later
today, and a hurricane in about 72 hours. After that time, the
cyclone is forecast to pass over slightly cooler waters and the
global models depict an increase in southwesterly upper-level flow
over the system by the end of the period. These less conducive
factors are expected to slow the intensification process toward the
end of the period. The NHC intensity forecast is a blend of the
IVCN multi-model consensus and the HFIP corrected consensus.
The initial motion of the depression is a somewhat uncertain 280/10
kt. A narrow mid-level ridge to the north of the depression is
forecast to build westward over the next few days which is expected
to steer the system westward to west-northwestward, and the track
guidance is in good agreement through 72 hours. After that time, a
weakness is forecast to develop in the ridge near 40 degrees west.
and the cyclone is expected to turn west-northwestward and then
northwestward between the ridge to its northeast and Tropical
Depression Seventeen to its southwest. Since there could be some
binary interaction between the two tropical cyclones later in the
period, the longer range track guidance is not in as good of
agreement, and there is more uncertainty than average in the
long-range track forecast.
Key Messages:
1. The depression is forecast to strengthen into a tropical storm
later today and tropical storm conditions are expected to spread
over portions of the Cabo Verde Islands later today and tonight. A
Tropical Storm Warning is in effect for those islands.
2. The depression is expected to bring locally heavy rainfall to
portions of the Cabo Verde Islands through Tuesday morning.
FORECAST POSITIONS AND MAX WINDS
INIT 07/0900Z 15.2N 20.3W 30 KT 35 MPH
12H 07/1800Z 15.6N 22.0W 35 KT 40 MPH
24H 08/0600Z 16.0N 24.5W 40 KT 45 MPH
36H 08/1800Z 16.4N 27.3W 50 KT 60 MPH
48H 09/0600Z 16.8N 30.2W 55 KT 65 MPH
60H 09/1800Z 17.4N 32.9W 60 KT 70 MPH
72H 10/0600Z 18.1N 35.5W 65 KT 75 MPH
96H 11/0600Z 19.7N 39.6W 70 KT 80 MPH
120H 12/0600Z 22.4N 43.2W 70 KT 80 MPH
$$
Forecaster Brown
Continue reading...