Tropical Storm Kevin Discussion Number 10
NWS National Hurricane Center Miami FL EP112021
300 PM MDT Mon Aug 09 2021
Visible satellite imagery and satellite wind data have revealed
today that Kevin is a poorly organized tropical cyclone. The
circulation is elongated from northeast-to-southwest, with one
dominant, exposed low-level cloud swirl pivoting around the larger
cyclonic gyre. The center has been initialized a little to the
southwest of the exposed swirl, closer to a generalized mean
cyclonic center. Satellite wind data also indicate that
tropical-storm-force winds are confined to the southern semicircle,
with a swath of 35-41 kt winds covering an area up to 110 n mi from
the estimated center. Assuming some instrument undersampling, and
based on the latest pair of 3.0 (45 kt) T-numbers from TAFB and SAB,
the initial intensity remains at 45 kt.
Kevin has not been able to get its act together over warm waters
and within the favorable thermodynamic environment, likely due to
moderate northeasterly shear and a subsequent lack of persistent
deep convection over the center. The overall environment that the
storm is interacting with is not expected to change much over the
next 36 h. And, since the structure of the cyclone is not conducive
for imminent strengthening, additional intensification is no longer
anticipated. After 36 h, Kevin will begin to move over decreasing
SSTs and into a more stable atmospheric environment. These
unfavorable thermodynamic conditions should cause the cyclone to
begin weakening. By 96 hours, the system is forecast to be over
water temperatures of less than 22 degrees C, which should result
in the cyclone degenerating into a remnant low. The latest NHC
intensity forecast was adjusted slightly lower once again, and is
in good agreement with the latest consensus intensity guidance.
Kevin continues to move to the west-northwest, or 300/08 kt, along
the southwestern periphery of a mid-level ridge. This steering
pattern is forecast by all of the forecast models to remain intact
for the next several days, resulting in a continued
west-northwestward motion. The track guidance has once again
shifted slightly northward after 24 h. Therefore, the latest NHC
track forecast was also nudged a little to the north, and lies on
the southern end of the tightly clustered track guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 09/2100Z 17.0N 112.2W 45 KT 50 MPH
12H 10/0600Z 17.7N 113.3W 45 KT 50 MPH
24H 10/1800Z 18.5N 114.7W 45 KT 50 MPH
36H 11/0600Z 19.3N 116.1W 45 KT 50 MPH
48H 11/1800Z 20.4N 117.8W 40 KT 45 MPH
60H 12/0600Z 21.2N 119.7W 35 KT 40 MPH
72H 12/1800Z 22.0N 121.9W 30 KT 35 MPH
96H 13/1800Z 23.6N 126.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 14/1800Z 25.5N 131.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Latto
NWS National Hurricane Center Miami FL EP112021
300 PM MDT Mon Aug 09 2021
Visible satellite imagery and satellite wind data have revealed
today that Kevin is a poorly organized tropical cyclone. The
circulation is elongated from northeast-to-southwest, with one
dominant, exposed low-level cloud swirl pivoting around the larger
cyclonic gyre. The center has been initialized a little to the
southwest of the exposed swirl, closer to a generalized mean
cyclonic center. Satellite wind data also indicate that
tropical-storm-force winds are confined to the southern semicircle,
with a swath of 35-41 kt winds covering an area up to 110 n mi from
the estimated center. Assuming some instrument undersampling, and
based on the latest pair of 3.0 (45 kt) T-numbers from TAFB and SAB,
the initial intensity remains at 45 kt.
Kevin has not been able to get its act together over warm waters
and within the favorable thermodynamic environment, likely due to
moderate northeasterly shear and a subsequent lack of persistent
deep convection over the center. The overall environment that the
storm is interacting with is not expected to change much over the
next 36 h. And, since the structure of the cyclone is not conducive
for imminent strengthening, additional intensification is no longer
anticipated. After 36 h, Kevin will begin to move over decreasing
SSTs and into a more stable atmospheric environment. These
unfavorable thermodynamic conditions should cause the cyclone to
begin weakening. By 96 hours, the system is forecast to be over
water temperatures of less than 22 degrees C, which should result
in the cyclone degenerating into a remnant low. The latest NHC
intensity forecast was adjusted slightly lower once again, and is
in good agreement with the latest consensus intensity guidance.
Kevin continues to move to the west-northwest, or 300/08 kt, along
the southwestern periphery of a mid-level ridge. This steering
pattern is forecast by all of the forecast models to remain intact
for the next several days, resulting in a continued
west-northwestward motion. The track guidance has once again
shifted slightly northward after 24 h. Therefore, the latest NHC
track forecast was also nudged a little to the north, and lies on
the southern end of the tightly clustered track guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 09/2100Z 17.0N 112.2W 45 KT 50 MPH
12H 10/0600Z 17.7N 113.3W 45 KT 50 MPH
24H 10/1800Z 18.5N 114.7W 45 KT 50 MPH
36H 11/0600Z 19.3N 116.1W 45 KT 50 MPH
48H 11/1800Z 20.4N 117.8W 40 KT 45 MPH
60H 12/0600Z 21.2N 119.7W 35 KT 40 MPH
72H 12/1800Z 22.0N 121.9W 30 KT 35 MPH
96H 13/1800Z 23.6N 126.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 14/1800Z 25.5N 131.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Latto
