000
WTPZ44 KNHC 252041
TCDEP4
 
Tropical Storm Iselle Discussion Number  10
NWS National Hurricane Center Miami FL       EP092026
200 PM PDT Tue Aug 25 2026

The structure of Iselle has significantly degraded during the past 
several hours, with the low-level circulation further detaching 
from the mid-level center located well to the northeast.  This 
change has caused any deep convection to be located well away from 
the center near the old mid-level center and is representative of 
a weakening cyclone.  A recent ASCAT scatterometer pass showed peak 
winds of about 45 kt, so the initial intensity is set to 50 kt, 
consistent with the low bias of the instrument.

Further weakening is anticipated due to continued shear, 
progressively cooler water and dry air entrainment near the core of 
the cyclone.  Perhaps because of the poor initial structure, 
Iselle isn't expected to be a particularly resilient cyclone, and 
no model shows organized deep convection beyond 36 hours.  The new 
NHC intensity forecast is lower than the last one, keeping the same 
general rate of weakening, but it shows a much earlier transition 
into a remnant low.
 
Satellite fixes show that the storm continues to move to the 
west-northwest, and little change in track is anticipated for the 
next couple of days due to ridging extending from the southern 
United States.  As the storm weakens, it should turn more westward 
by Thursday due to the cyclone becoming steered more by the 
low-level flow.  The guidance is shifting southward, consistent 
with a decaying system, so the new forecast is shifted equatorward, 
closest to the Google DeepMind ensemble mean.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/2100Z 21.0N 121.8W   50 KT  60 MPH
 12H  26/0600Z 21.3N 123.0W   40 KT  45 MPH
 24H  26/1800Z 21.8N 124.7W   35 KT  40 MPH
 36H  27/0600Z 22.4N 126.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  27/1800Z 23.0N 128.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  28/0600Z 23.5N 130.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  28/1800Z...DISSIPATED
 
$$
Forecaster Blake/Evans