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Tropical Storm Karina Discussion Number 13
NWS National Hurricane Center Miami FL EP162020
Issued by NWS Central Pacific Hurricane Center Honolulu HI
800 PM PDT Tue Sep 15 2020
Satellite imagery shows that Karina's outflow has improved over the
past 6 hours, but persistent deep convection over the low-level
center has shown some signs of warming/weakening in the last couple
hours. The initial intensity for this advisory is maintained at 50
kt, primarily based on a blend of subjective Dvorak intensity
estimates of 45-55 kt from SAB/TAFB/HFO.
Karina is moving toward the northwest at 10 kt (310/10 kt), steered
by a mid- and upper-level ridge to the northeast and north,
respectively. Although some relaxation of the recent northeasterly
to easterly shear is expected to continue in the short-term,
gradual weakening is expected as Karina is now over sub-26C water.
As Karina rounds the southwestern portion of the deep-layer ridge in
about 24 hours, south to southwesterly shear is expected to
increase as the cyclone moves over even cooler waters and ingests
increasingly dry air. This will lead to the demise of the cyclone,
and Karina is expected to degenerate to a remnant low in a couple
of days, dissipating shortly thereafter.
As the system weakens, it will be steered by the low-level
northeasterly trade wind flow supplied by a surface high centered to
the distant northwest, causing a slowing in forward speed, and a
turn toward the west and southwest. The new official track forecast
has changed little from the previous, and lies very close to the
dynamical consensus TVCE. The new intensity forecast is little
changed, and closely follows both the statistical and dynamical
guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 16/0300Z 21.3N 123.0W 50 KT 60 MPH
12H 16/1200Z 22.1N 124.2W 45 KT 50 MPH
24H 17/0000Z 23.0N 125.6W 40 KT 45 MPH
36H 17/1200Z 23.4N 126.7W 35 KT 40 MPH
48H 18/0000Z 23.5N 127.8W 30 KT 35 MPH
60H 18/1200Z 23.2N 129.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 19/0000Z 22.5N 130.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 20/0000Z...DISSIPATED
$$
Forecaster Birchard
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