Tropical Cyclone Discussion

821
WTPZ41 KNHC 280837
TCDEP1
 
Tropical Storm Karina Discussion Number   3
NWS National Hurricane Center Miami FL       EP112026
200 AM MST Fri Aug 28 2026
 
Karina's structure on satellite imagery tonight is slowly evolving,
with a concentrated burst of deep convection with cloud top
temperatures below -80 C occurring near and to the east of the
center. However, scatterometer wind data around 05 UTC indicated
that the center was still on the edge of this convective burst, and
remains a bit elongated on its southwest end, where the cyclone is
interacting with the larger monsoon trough. The peak wind retrieval
was 41 kt, and that combined with little change in the subjective
or objective intensity estimates supports maintaining 45 kt for this
advisory.
 
The tropical storm is moving on a general northwest heading at 
310/11 kt. An established mid-level ridge over the southwestern U.S. 
should maintain this general motion over the next couple of days. 
Thereafter, this ridging begins to extend more zonally to the north 
of Karina, allowing the track of the cyclone to turn more westward 
in the 48-72 h time frame. Towards the end of the forecast period, 
guidance suggests this ridge will become eroded by a mid- to 
upper-level trough, which could result in Karina making a turn back 
to the northwest. The track guidance this morning has shifted a 
little south and west compared to the previous cycle, and the NHC 
forecast track has also been shifted in this direction, blending the 
latest HFIP Corrected Consensus Approach (HCCA) and Google DeepMind 
(GDMI) aids.

Karina's wind field diagnosed by scatterometer earlier is still 
fairly broad, and it will likely take a bit more time for the 
cyclone to develop an inner core. However, environmental conditions 
beyond the next 24 h remain quite favorable for intensification, 
with low shear, warm waters, and a sufficiently moist deep-layer 
troposphere. SHIPS-RII guidance also continues to indicate elevated 
probabilities of rapid intensification that are 4-5 times the 
climatological mean. Thus, significant intensification is forecasted 
over the next 2-3 days, and the latest NHC intensity forecast is 
higher than the previous one, showing a 110 kt peak in about 72 h, 
though this forecast is still under some of the more aggressive 
guidance (HCCA, GDMI) but above some of the hurricane-regional model 
guidance this cycle (HAFS-A/B). In days 4-5 Karina should encounter 
a more stable environment as it approaches the northern edge of the 
26 C isotherm, and weakening is shown to begin by the end of the 
forecast period.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0900Z 12.7N 114.3W   45 KT  50 MPH
 12H  28/1800Z 13.6N 115.5W   55 KT  65 MPH
 24H  29/0600Z 15.1N 116.9W   65 KT  75 MPH
 36H  29/1800Z 16.5N 118.9W   80 KT  90 MPH
 48H  30/0600Z 17.5N 120.7W   90 KT 105 MPH
 60H  30/1800Z 18.2N 122.5W  100 KT 115 MPH
 72H  31/0600Z 18.4N 124.2W  110 KT 125 MPH
 96H  01/0600Z 19.3N 127.3W  100 KT 115 MPH
120H  02/0600Z 20.5N 129.5W   80 KT  90 MPH