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Tropical Storm Karina Discussion Number 9
NWS National Hurricane Center Miami FL EP162020
Issued by NWS Central Pacific Hurricane Center Honolulu HI
800 PM PDT Mon Sep 14 2020
Karina may not have reached its peak after all. The northeasterly
vertical wind shear appears to have eased a bit, allowing
the dense cirrus overcast from the central convection to fully
obscure the low level cloud center. The cyclone also appears to be
better organized than 24 hours ago. As a result, most of the Dvorak
intensity estimates have increased, with ADT up to 39 kt, and PHFO
and TAFB indicating 55 kt. SAB was unchanged from the 6 hours ago at
35 kt. Based on a blend of the estimates, the initial intensity for
this advisory has been increased to 45 kt. The 12 ft seas radii have
also been adjusted based on guidance from TAFB.
Moderate shear should continue to affect Karina for another
12 to 24 hours. The shear is forecast to weaken after that, but by
then the cyclone is expected to be over sub-26 degree C sea surface
temperatures. There is still a narrow window for additional
intensification, but most of the guidance holds the intensity for
another 12 to 24 hours, with gradual weakening occurring afterward.
The forecast holds Karina at 45 kt for 24 hours, followed by
weakening to post-tropical remnant low status by 72 hours. This is
close to the HCCA guidance.
The initial motion for this advisory is 310/10 kt. Karina is
forecast to continue moving northwestward to the southwest of a
mid-level anticyclone. This motion is expected to continue through
60 to 72 hours. Karina should turn toward the southwest as deep
convection ceases and the cyclone becomes steered by the low level
flow. The objective guidance is tightly packed through around 60
hours, with variations occurring thereafter regarding when the
southwestward turn will occur. The forecast track is close to the
previous forecast and closely follows the consensus guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 15/0300Z 19.1N 119.8W 45 KT 50 MPH
12H 15/1200Z 20.0N 120.7W 45 KT 50 MPH
24H 16/0000Z 21.3N 122.2W 45 KT 50 MPH
36H 16/1200Z 22.4N 123.7W 40 KT 45 MPH
48H 17/0000Z 23.3N 124.9W 35 KT 40 MPH
60H 17/1200Z 23.8N 125.8W 25 KT 30 MPH
72H 18/0000Z 23.9N 126.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 19/0000Z 23.5N 128.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 20/0000Z...DISSIPATED
$$
Forecaster Kodama
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