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Tropical Storm Karina Discussion Number 11
NWS National Hurricane Center Miami FL EP162020
800 AM PDT Tue Sep 15 2020
Karina has changed little in organization over the past several
hours with a concentrated area of deep convection mostly over the
southwestern portion of the circulation and over the estimated
position of the low-level center. The initial intensity is kept at
50 kt based on a blend of the latest Dvorak CI numbers from TAFB and
SAB and the objective UW-CIMSS ADT.
Karina is now crossing the 26 isotherm, so it is unlikely that any
further strengthening will occur. The cyclone is forecast to move
over progressively cooler waters and into a drier, more stable
atmosphere over the next couple of days. These conditions should
induce a weakening trend soon, and the deep convection is expected
to gradually wane during that time. Karina is forecast to become a
convection-free remnant low by 60 h, or perhaps a little sooner. The
latest NHC intensity forecast is in good agreement with the various
guidance aids.
The initial motion of the tropical storm is 310/09 kt, as it
continues to move along the periphery of a mid-level ridge to its
northeast. This general motion should continue while the system
maintains convection. As the system becomes devoid of convection, a
turn to the west and west-southwest is anticipated as the cyclone
moves within the low-level flow.
FORECAST POSITIONS AND MAX WINDS
INIT 15/1500Z 20.4N 121.1W 50 KT 60 MPH
12H 16/0000Z 21.3N 122.2W 45 KT 50 MPH
24H 16/1200Z 22.4N 123.9W 40 KT 45 MPH
36H 17/0000Z 23.3N 125.2W 35 KT 40 MPH
48H 17/1200Z 23.7N 126.2W 30 KT 35 MPH
60H 18/0000Z 23.9N 127.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 18/1200Z 23.5N 128.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 19/1200Z 22.6N 130.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 20/1200Z...DISSIPATED
$$
Forecaster Latto
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