Tropical Cyclone Discussion

933
WTPZ45 KNHC 161457
TCDEP5
 
Tropical Storm Simon Discussion Number  37
NWS National Hurricane Center Miami FL       EP202026
800 AM MST Fri Oct 16 2026
 
Southwesterly vertical wind shear and dry mid-level air are taking a 
toll on Simon this morning. An earlier AMSR-3 microwave pass 
indicated that the mid-level center was displaced to the northeast 
of the low-level center, a trend also reflected in bursts of deep 
convection to the north and east of the center over the past 
several hours. The pass also suggested that the low-level center 
was slightly farther north than previously estimated, and the 
initial position was adjusted accordingly. The latest TAFB Dvorak 
intensity estimate was 2.0/30 kt. However, convective organization 
has changed little, so the intensity is maintained at 35 kt for this 
advisory. 

Simon is moving northwestward at 315/8 kt. Given the storm's shallow 
nature, its motion is being steered by the low- and mid-level flow, 
characterized by troughing to the west and a mid-level ridge to the 
northeast. This general motion is expected to continue over the next 
24-36 h, bringing Simon parallel to the coast of Baja California 
Sur. Following the northward adjustment of the initial position, the 
latest NHC track forecast has been shifted slightly to the right of 
the previous forecast and lies near the corrected consensus (HCCA) 
track. 

Despite moving over very warm waters (28-30 C), significant 
southwesterly wind shear and increasingly dry mid-level air are 
expected to support continued weakening. In fact, simulated 
satellite imagery from the ECMWF and GFS suggest that Simon may 
struggle to maintain organized deep convection by late tonight. The 
official forecast calls for Simon to become a post-tropical remnant 
low within 24 h, though this transition may occur sooner. 
Dissipation is expected by 48 h. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/1500Z 20.6N 109.5W   35 KT  40 MPH
 12H  17/0000Z 21.6N 110.9W   30 KT  35 MPH
 24H  17/1200Z 22.7N 112.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  18/0000Z 24.0N 114.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  18/1200Z...DISSIPATED