Tropical Cyclone Discussion

633
WTPZ41 KNHC 311455
TCDEP1
 
Hurricane Karina Discussion Number  17
NWS National Hurricane Center Miami FL       EP112026
500 AM HST Mon Aug 31 2026
 
Conventional satellite imagery shows that the inner core structure
of Karina has become a little less defined.  The cloud tops in
the northwestern portion of the eyewall have warmed to around -60
C, and the latest TAFB Dvorak satellite intensity estimate is
T5.5/102 kt.  The CMISS satellite intensity objective techniques 
range from 115 to 129 kt.  Based on these data, the initial
intensity remains at 120 kt.
 
Karina continues to move generally westward, estimated at 275
degrees at 7 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 several days.
Toward 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 meridionally oriented ridge takes its place to the
northwest of Karina, which should act to gradually slow its forward
motion.  The current NHC forecast track has been adjusted
slightly to the south of the previous track based on the guidance
from the HFIP Corrected Consensus Approach (HCCA) and Google
DeepMind (GDMI) guidance.
 
While environmental conditions should remain favorable in the short
term, the hurricane could experience some intensity fluctuations due
to inner-core changes.  Karina may develop annular characteristics
that could help reduce the rate of weakening the cyclone is forecast
to undergo. The current SHIPS statistical intensity models indicate
that relative humidity beyond 72 h will drop below 40%, 
Consequently, abundant dry, stable air will impact the hurricane.   
Once Karina moves over cooler ocean waters past 96 h, and more dry 
air is pulled into the hurricane's inner core, the rate of 
weakening could increase at a faster rate indicated in the 
official forecast which is close to the HCCA corrected consensus.
 
Karina's wind radii have been adjusted based on 0553 UTC METOP-B/C
ASCAT overpasses, and 0757 UTC OSCAT data.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  31/1500Z 17.4N 125.1W  120 KT 140 MPH
 12H  01/0000Z 17.6N 126.4W  120 KT 140 MPH
 24H  01/1200Z 18.0N 128.4W  115 KT 130 MPH
 36H  02/0000Z 18.4N 130.3W  110 KT 125 MPH
 48H  02/1200Z 18.8N 132.3W  100 KT 115 MPH
 60H  03/0000Z 19.2N 134.2W   95 KT 110 MPH
 72H  03/1200Z 19.5N 136.1W   90 KT 105 MPH
 96H  04/1200Z 20.2N 139.9W   80 KT  90 MPH
120H  05/1200Z 21.1N 143.7W   70 KT  80 MPH