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Tropical Storm Iselle Discussion Number   8
NWS National Hurricane Center Miami FL       EP142020
200 AM PDT Fri Aug 28 2020
 
Iselle continues to produce deep convection near the center and on
its west side.  This asymmetric cloud pattern is due to a
moderate amount of easterly wind shear.  An ASCAT-A overpass from a
few hours ago showed maximum winds in the 45-50 kt range, and based
on that data, the initial intensity is nudged up to 50 kt.  The
intensity models suggest that little change in strength is likely
today as Iselle remains in the current environment of easterly
shear.  However, gradual weakening should begin by tonight and
continue through the weekend as Iselle moves over progressively
cooler waters and into a more stable air mass.  The NHC intensity
forecast follows the trend of the models, and predicts Iselle
to weaken to a tropical depression in a couple of days and to a
remnant low shortly thereafter.

Iselle is moving slowly northeastward toward Tropical Storm Hernan 
located near the coast of west-central Mexico.  Iselle should 
generally move northeastward to north-northeastward as it remains 
embedded in a trough with Hernan for about another day.  Thereafter, 
Hernan is expected to dissipate and a low- to mid-level ridge should 
cause Iselle to turn to the northwest.  This track keeps Iselle well 
offshore the Baja California peninsula.  The models are in fair 
agreement, and this forecast lies close to the various consensus 
aids.
 
The initial wind radii have been modified based on the
aforementioned ASCAT data.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0900Z 17.9N 115.0W   50 KT  60 MPH
 12H  28/1800Z 18.7N 114.5W   50 KT  60 MPH
 24H  29/0600Z 20.1N 114.1W   45 KT  50 MPH
 36H  29/1800Z 21.7N 114.1W   40 KT  45 MPH
 48H  30/0600Z 23.0N 114.8W   30 KT  35 MPH
 60H  30/1800Z 23.9N 115.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  31/0600Z 24.2N 116.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  01/0600Z 24.5N 117.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  02/0600Z...DISSIPATED
 
$$
Forecaster Cangialosi
 
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