Tropical Cyclone Discussion

486
WTPZ44 KNHC 250237
TCDEP4
 
Tropical Storm Iselle Discussion Number   7
NWS National Hurricane Center Miami FL       EP092026
800 PM PDT Mon Aug 24 2026
 
Based on the most recent satellite imagery, it appears that the 
moderate west-northwesterly shear could be starting to impact 
Iselle, as the bulk of the convection is being pushed away from the 
center. The cyclone still has a training curved band that extends 
pretty far south on the east side. The most recent subjective Dvorak 
classification from TAFB is T3.5/55 kt, and the objective satellite 
intensity estimates range from 50 to 67 kt. Based on the given data, 
the initial intensity is being kept at 60 kt for this advisory.
 
The initial motion estimate is unchanged from the previous advisory,
northwestward, or 315/10 kt.  A mid-level ridge north of Iselle is
forecast to strengthen, causing Iselle to turn west-northwestward on
Tuesday, and that motion should then continue through the end of the
week.  The latest NHC track forecast is quite similar to the
previous one, and lies very close to the HFIP Corrected Consensus
(HCCA) and the Google DeepMind Ensemble Mean (GDMI).

The storm is still over warm waters and within a moist environment, 
but with moderate west-northwesterly vertical wind shear, there is 
likely a limit to how much strength Iselle could gain. It is still 
possible that Iselle could get to hurricane intensity, however, the 
time to do so is limited. After the next 12 h, the environment is 
expected to become more hostile as the wind shear, dry air, and 
cooler sea-surface temperatures will have a negative impact on the 
cyclone's intensity. The simulated ECMWF and GFS satellite imagery 
suggest that Iselle could become a a remnant low as early as 
Wednesday night and then could be dissipate around day 4. It is 
possible that this system could dissipate even sooner than what is 
currently forecasted.  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0300Z 20.1N 118.6W   60 KT  70 MPH
 12H  25/1200Z 20.7N 119.9W   55 KT  65 MPH
 24H  26/0000Z 21.3N 121.7W   50 KT  60 MPH
 36H  26/1200Z 21.8N 123.7W   45 KT  50 MPH
 48H  27/0000Z 22.6N 125.1W   35 KT  40 MPH
 60H  27/1200Z 23.2N 127.0W   30 KT  35 MPH
 72H  28/0000Z 23.6N 129.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  29/0000Z...DISSIPATED