Tropical Storm Carlos Discussion Number 5
NWS National Hurricane Center Miami FL EP032021
200 PM PDT Sun Jun 13 2021
Deep convection has managed to persist over the center of Carlos
throughout the day today, although the appearance of this convection
has become more ragged as the day has progressed. The blended CI
values from TAFB and SAB suggest the system still has an intensity
of 45 kt. A recent ASCAT overpass only partially captured the
circulation with peak wind vectors of 39 kt. Compensating for
possible undersampling by the instrument over only a portion of
such a compact cyclone, maintaining 45 kt seems reasonable for the
initial advisory intensity.
Dry and stable air lies just to the north and west of Carlos, and
occasional intrusions of this air into the cyclone's circulation
could disrupt convection. However, the overnight diurnal convective
maximum could overcome these intrusions over the next couple of
nights. Therefore, only slight weakening is indicated through that
time period. By 48 h, Carlos is expected to move into the stable
airmass which should further disrupt its convection, causing
additional weakening. By late in the forecast period the cyclone
is forecast to be near or have crossed the 26 degree C SST
isotherm. This should cause any remaining convection to gradually
dissipate. Although not shown in the official forecast, it is
possible Carlos will degenerate into a remnant low by the end of
the forecast period, as suggested by the GFS. The latest NHC
intensity forecast is very near the various multi-model consensus
solutions.
Carlos is beginning to show signs of slowing and turning to the
left, with the initial motion now 260/6 kt. Model guidance remains
in good agreement through 48 h, with the storm slowing and turning
west-southwest as a mid-level ridge becomes oriented SW-NE to the
north of the cyclone. There is still a vast amount of track guidance
spread beyond 72 h, but not as much as earlier today. The GFS, which
continues to be the easternmost solution has shifted well west of
its previous track, showing Carlos turning northwest in a few days
in response to a building ridge to its east, and weakening ridge to
the north. The remaining guidance maintains the ridge to the north
and shows Carlos turning west by midweek, then west-northwest by
late this week. The official NHC forecast is near the previous one
through 48 h. Beyond 48 h, large adjustments were required to
accommodate the continuing westward trends in the guidance.
Despite the abrupt shift in the official forecast for the latter
half of the period, it remains well east of the consensus and the
majority of available track guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 13/2100Z 11.7N 126.6W 45 KT 50 MPH
12H 14/0600Z 11.4N 127.4W 40 KT 45 MPH
24H 14/1800Z 11.0N 128.3W 40 KT 45 MPH
36H 15/0600Z 10.6N 129.2W 40 KT 45 MPH
48H 15/1800Z 10.4N 130.0W 35 KT 40 MPH
60H 16/0600Z 10.3N 130.8W 30 KT 35 MPH
72H 16/1800Z 10.3N 131.3W 30 KT 35 MPH
96H 17/1800Z 10.7N 132.0W 25 KT 30 MPH
120H 18/1800Z 11.4N 132.7W 25 KT 30 MPH
$$
Forecaster Latto
NWS National Hurricane Center Miami FL EP032021
200 PM PDT Sun Jun 13 2021
Deep convection has managed to persist over the center of Carlos
throughout the day today, although the appearance of this convection
has become more ragged as the day has progressed. The blended CI
values from TAFB and SAB suggest the system still has an intensity
of 45 kt. A recent ASCAT overpass only partially captured the
circulation with peak wind vectors of 39 kt. Compensating for
possible undersampling by the instrument over only a portion of
such a compact cyclone, maintaining 45 kt seems reasonable for the
initial advisory intensity.
Dry and stable air lies just to the north and west of Carlos, and
occasional intrusions of this air into the cyclone's circulation
could disrupt convection. However, the overnight diurnal convective
maximum could overcome these intrusions over the next couple of
nights. Therefore, only slight weakening is indicated through that
time period. By 48 h, Carlos is expected to move into the stable
airmass which should further disrupt its convection, causing
additional weakening. By late in the forecast period the cyclone
is forecast to be near or have crossed the 26 degree C SST
isotherm. This should cause any remaining convection to gradually
dissipate. Although not shown in the official forecast, it is
possible Carlos will degenerate into a remnant low by the end of
the forecast period, as suggested by the GFS. The latest NHC
intensity forecast is very near the various multi-model consensus
solutions.
Carlos is beginning to show signs of slowing and turning to the
left, with the initial motion now 260/6 kt. Model guidance remains
in good agreement through 48 h, with the storm slowing and turning
west-southwest as a mid-level ridge becomes oriented SW-NE to the
north of the cyclone. There is still a vast amount of track guidance
spread beyond 72 h, but not as much as earlier today. The GFS, which
continues to be the easternmost solution has shifted well west of
its previous track, showing Carlos turning northwest in a few days
in response to a building ridge to its east, and weakening ridge to
the north. The remaining guidance maintains the ridge to the north
and shows Carlos turning west by midweek, then west-northwest by
late this week. The official NHC forecast is near the previous one
through 48 h. Beyond 48 h, large adjustments were required to
accommodate the continuing westward trends in the guidance.
Despite the abrupt shift in the official forecast for the latter
half of the period, it remains well east of the consensus and the
majority of available track guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 13/2100Z 11.7N 126.6W 45 KT 50 MPH
12H 14/0600Z 11.4N 127.4W 40 KT 45 MPH
24H 14/1800Z 11.0N 128.3W 40 KT 45 MPH
36H 15/0600Z 10.6N 129.2W 40 KT 45 MPH
48H 15/1800Z 10.4N 130.0W 35 KT 40 MPH
60H 16/0600Z 10.3N 130.8W 30 KT 35 MPH
72H 16/1800Z 10.3N 131.3W 30 KT 35 MPH
96H 17/1800Z 10.7N 132.0W 25 KT 30 MPH
120H 18/1800Z 11.4N 132.7W 25 KT 30 MPH
$$
Forecaster Latto
