Tropical Cyclone Discussion

605
WTPZ41 KNHC 310847
TCDEP1
 
Hurricane Karina Discussion Number  16
NWS National Hurricane Center Miami FL       EP112026
1100 PM HST Sun Aug 30 2026

Karina has continued to rapidly intensify. Since the previous 
advisory, cold cloud top temperatures below -75 C wrapped back 
around northern side of the hurricane while the eye is making an 
attempt to clear out some. In response, the objective UW-CIMSS ADT 
intensity estimate, after plateauing earlier, has begun to rise 
again, with the latest value at T6.6/129 kt. It is worth noting the 
majority of the other objective estimates are 6-12 h old, likely to 
to the lack of recent microwave imagery. The 06 UTC TAFB subjective 
Dvorak estimate was constrained lower at CI 5.5/102 kt, though the 
Data-T number was also 6.5/125 kt. The initial intensity will be 
set at 125 kt for this advisory, making Karina a formidable Category 
4 hurricane.  

Karina continues to move off generally westward, estimated at 275 
degrees at 8 kt. A narrow but extensive mid-level ridge is parked to 
the north of the hurricane, and this feature will likely remain the 
dominant steering impact on Karina over the next 3-5 days. Towards 
the end of the forecast period, the original ridge becomes eroded by 
a mid-latitude trough digging into the western US coast, but a more 
meridional oriented ridge takes its place to the northwest of 
Karina, which should act to gradually slow its forward motion. Once 
again there has been another leftward shift in the guidance, and the 
latest NHC track forecast has also been adjusted in that direction, 
splitting the difference between the latest HFIP Corrected Consensus 
Approach (HCCA) and Google DeepMind (GDMI) guidance. 

Environmental conditions over Karina remain favorable, and there is 
still some time for the hurricane to intensify a bit more in the 
short-term. However, it also is possible the system will soon start 
to undergo inner-core fluctuations like eyewall replacement cycles 
(ERCs), though there has not been any recent microwave imagery to 
determine if such an event is preparing to take place. Another 
factor to consider is that beyond the next 24-36 h, Karina might 
find itself in environmental conditions favorable for the hurricane 
to develop Annular characteristics, which could slow its rate of 
weakening despite the storm moving over gradually cooling 
sea-surface temperatures. Thus, the NHC intensity forecast is on the 
high side of the guidance envelope for a large portion of the 
forecast period, sticking pretty close to the latest HCCA intensity 
forecast. A somewhat faster rate of weakening is possible by the end 
of the forecast period when Karina is forecast to cross the 26 C 
sea-surface temperature isotherm. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  31/0900Z 17.2N 124.4W  125 KT 145 MPH
 12H  31/1800Z 17.4N 125.8W  130 KT 150 MPH
 24H  01/0600Z 17.7N 127.6W  125 KT 145 MPH
 36H  01/1800Z 18.1N 129.6W  115 KT 130 MPH
 48H  02/0600Z 18.6N 131.7W  110 KT 125 MPH
 60H  02/1800Z 19.1N 133.6W  105 KT 120 MPH
 72H  03/0600Z 19.4N 135.7W  100 KT 115 MPH
 96H  04/0600Z 20.0N 139.5W   90 KT 105 MPH
120H  05/0600Z 21.0N 143.5W   75 KT  85 MPH