592 
WTPZ44 KNHC 260838
TCDEP4
 
Tropical Storm Iselle Discussion Number  12
NWS National Hurricane Center Miami FL       EP092026
200 AM PDT Wed Aug 26 2026
 
Moderate northerly wind shear and dry air entrainment are affecting 
Iselle this morning. An earlier GPM microwave pass indicated that 
the circulation is better established to the north and east of the 
center, with less definition on the southern and western sides. This 
structure is consistent with infrared satellite imagery, which shows 
shower and thunderstorm activity concentrated primarily northeast of 
the center. However, a recent ASCAT scatterometer pass indicated 
that winds of 40-45 kt remain present in the northeastern quadrant. 
The 0600 UTC Dvorak intensity estimate from TAFB was 3.0/45 kt, 
while objective intensity estimates from UW-CIMSS range from 26-44 
kt. Given the scatterometer data and subjective Dvorak estimate, 
the intensity is set at 45 kt for this advisory. 

Iselle will continue on a west-northwestward heading over the next 
couple of days as a ridge builds to the north of the cyclone. 
Increasing wind shear, cooler sea surface temperatures and drier 
mid-level air will promote gradual weakening through late this week, 
and Iselle may struggle to maintain organized convection as early as 
tonight. The latest NHC forecast calls for Iselle to become 
post-tropical by 24 h and degenerate to a remnant low by 36 h. Only 
minor adjustments were made to the track and intensity forecasts for 
this advisory cycle. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  26/0900Z 21.8N 123.5W   45 KT  50 MPH
 12H  26/1800Z 22.2N 124.6W   40 KT  45 MPH
 24H  27/0600Z 22.8N 126.4W   35 KT  40 MPH...POST-TROPICAL
 36H  27/1800Z 23.5N 128.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  28/0600Z 23.8N 130.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  28/1800Z 24.3N 132.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  29/0600Z...DISSIPATED
 
$$
Forecaster Adams