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Tropical Storm Kevin Discussion Number 6
NWS National Hurricane Center Miami FL EP112021
300 PM MDT Sun Aug 08 2021
The earlier burst of deep convection almost completely dissipated,
leaving the core of the low-level circulation briefly exposed.
However, over the past couple of hours new convection has
redeveloped over the center of Kevin. This disruption, possibly
aided by moderate northeasterly shear, put a temporary pause on the
cyclone's strengthening. The latest Dvorak T-numbers from TAFB and
SAB have decreased to 3.0 (45 kt), while the CI-values remain at 3.5
(55 kt). Based on a blend of these numbers, the estimated initial
advisory intensity remains 50 kt.
Kevin is forecast to remain over warm waters while embedded in a
moist and unstable atmospheric environment for the next 48 h or so.
The main inhibiting factor for intensification is the persistent
vertical wind shear, which is forecast to persist for the next few
days. Kevin is forecast by all of the intensity guidance to overcome
this shear, and slowly strengthen over the next two days. After 60
h, Kevin should begin to move over decreasing SSTs and into a more
stable atmospheric environment, which should cause the cyclone to
steadily weaken. By 120 h, the system is forecast to be over waters
of less than 23 degrees C, likely causing the cyclone to become
devoid of deep convection. The only notable change in the latest NHC
forecast from the previous one was to introduce the mention of the
system as post-tropical by day 5. Otherwise, the latest forecast
remains near the IVCN consensus aid.
Kevin continues to move westward, or 270/7 kt. There is no change to
the forecast track reasoning. A mid- to upper-level trough west of
the Baja California peninsula is expected to weaken the western
portion of the ridge that is currently steering Kevin westward.
This should cause the cyclone to turn west-northwestward overnight
and this west-northwestward heading is then expected to continue for
the remainder of the forecast period. The latest track guidance is
in very good agreement on this scenario, and the NHC track forecast
is little changed from the previous one.
FORECAST POSITIONS AND MAX WINDS
INIT 08/2100Z 15.8N 109.7W 50 KT 60 MPH
12H 09/0600Z 16.0N 110.8W 55 KT 65 MPH
24H 09/1800Z 16.6N 112.0W 60 KT 70 MPH
36H 10/0600Z 17.3N 113.5W 65 KT 75 MPH
48H 10/1800Z 18.1N 115.0W 70 KT 80 MPH
60H 11/0600Z 19.0N 116.8W 65 KT 75 MPH
72H 11/1800Z 19.8N 118.4W 60 KT 70 MPH
96H 12/1800Z 21.5N 122.3W 50 KT 60 MPH
120H 13/1800Z 23.0N 126.8W 35 KT 40 MPH...POST-TROPICAL