Tropical Cyclone Discussion

913
WTPZ43 KNHC 280246
TCDEP3
 
Tropical Storm Rachel Discussion Number   4
NWS National Hurricane Center Miami FL       EP182026
900 PM CST Sun Sep 27 2026
 
The last few visible satellite images of the day indicate that 
Rachel continues to have a broad center. A recently received 
Oceansat-3 scatterometer pass that partially sampled the system a 
few hours ago indicated winds to at least 35 kt about 120 n mi west 
of the center. Objective satellite intensity estimates range from 
35-40 kt and the Dvorak classification from TAFB is T2.5/35 kt. 
Based on these data, and the broad structure of the tropical 
cyclone, the initial intensity is maintained at 35 kt for this 
advisory.
 
Rachel is moving westward at 280/6 kt. The overall track philosophy
has not changed for this forecast. A deep-layer ridge building over
Mexico is expected to steer the cyclone west-northwestward at a
faster forward speed through mid-week. On Thursday, a weakness in
the ridge, caused by a trough over the southwestern United States,
will cause the cyclone to move more slowly on a similar
northwestward heading. The new track forecast is similar to the
advisory, and blends the Google DeepMind (GDM) and HFIP Corrected
Consensus Aid (HCCA).
 
The tropical storm continues to endure approximately 20 kt of
northeasterly shear, which is clearly evident on satellite imagery.
Given the broad structure and moderate to high wind shear, gradual
intensification is forecast over the next couple of days. The shear
is expected to subside early next week and intensification is likely
to continue thereafter, with Rachel forecast to become a hurricane
on Tuesday. Rachel could then track over the cool wake from
Hurricane Polo, though recent drifter data captured vertical
profiles that show high ocean heat content (OHC) persists in the
region. The intensity forecast is on the higher end of the guidance
envelope, and blends the GDM and HCCA solutions.

The analyzed and forecast tropical storm force wind radii for Rachel 
are larger in this forecast than the previous one. Due to the 
proximity of tropical storm force winds to the coast, the government 
of Mexico has issue a Tropical Storm Watch from Punta San Telmo to 
Playa Perula.

Key Messages:

1. Although the core of Rachel is forecast to remain offshore of 
Mexico, tropical storm force winds are possible along a portion of 
the coast of southwestern Mexico in the Tropical Storm Watch area 
on Tuesday.

2. Large waves could produce life-threatening surf and rip current 
conditions along portions of the southwestern coast of Mexico during 
the next several days.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  28/0300Z 12.9N  99.8W   35 KT  40 MPH
 12H  28/1200Z 13.3N 100.9W   45 KT  50 MPH
 24H  29/0000Z 14.2N 102.6W   55 KT  65 MPH
 36H  29/1200Z 15.2N 104.3W   60 KT  70 MPH
 48H  30/0000Z 16.4N 106.0W   70 KT  80 MPH
 60H  30/1200Z 17.5N 107.2W   80 KT  90 MPH
 72H  01/0000Z 18.4N 108.2W   85 KT 100 MPH
 96H  02/0000Z 19.1N 109.0W   85 KT 100 MPH
120H  03/0000Z 20.0N 109.7W   85 KT 100 MPH