153
WTPZ43 KNHC 290250
TCDEP3

Tropical Storm Rachel Discussion Number   8
NWS National Hurricane Center Miami FL       EP182026
900 PM CST Mon Sep 28 2026

The satellite-observed structure of Rachel has improved this
evening. While the storm is still clearly feeling the effects of
northerly shear, proxy-visible and infrared satellite images show
the low-level center is tucked underneath the northern side of the
cold dense overcast. TAFB also noted an improvement in the satellite
structure of Rachel with their latest T3.0 Dvorak classification,
and the various UW-CIMSS objective estimates generally range from
44-54 kt. Based on a blend of these estimates, the initial intensity
is set at 50 kt.

Rachel is moving west-northwestward (300/9 kt) along the southwest
side of a mid-level ridge over northern Mexico. A deep-layer trough
over the southwestern United States is expected to move eastward
during the next couple of days, which should erode the ridge and
cause Rachel to turn northwestward at a slower forward speed within
weaker steering currents through midweek. By late week, the trough
is forecast to lift out and the ridge should become reestablished to
the north, with Rachel expected to resume a west-northwestward
motion. Overall, the track model guidance trended slightly faster
this cycle, and the NHC forecast has been adjusted to fall between
the latest simple (TVCN) and corrected (HCCA) consensus aids.

In general, the models agree that Rachel should intensify over very
warm SSTs (29-30 deg C) with abundant mid-level moisture and a
divergent upper-level environment. Moderate vertical wind shear
appears to be the only limiting factor, though it is forecast to
gradually decrease through midweek. Since the tropical storm is
sheared and currently lacks an inner core, only gradual
strengthening is forecast tonight. Thereafter, there is fairly large
spread in the intensity guidance, with some models including Google
DeepMind, COAMPS-TC, and HCCA showing Rachel reaching major
hurricane status. The updated NHC intensity forecast is not as
aggressive as these models but has been raised from the previous
prediction, slightly higher than the simple consensus (IVCN) but
still well below the latest HCCA and GDMI aids. The NHC forecast
levels off in the 60-120 h time frame based on mixed signals in the
guidance, perhaps a result of Rachel encountering some cooler waters
left behind in the wake of Hurricane Polo.


Key Messages:

1. Although the core of Rachel is forecast to remain offshore of
Mexico, tropical-storm-force winds are expected along a portion of
the coast of southwestern Mexico in the Tropical Storm Warning area
on Tuesday. Tropical storm conditions are possible in the watch
area Tuesday night or on Wednesday.

2. Outer bands from Rachel will bring locally heavy rainfall to
portions of coastal southwest Mexico through Thursday. This rainfall
may produce areas of flooding and mudslides, especially in areas of
steep terrain.

3. 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  29/0300Z 14.5N 102.9W   50 KT  60 MPH
 12H  29/1200Z 15.2N 104.3W   55 KT  65 MPH
 24H  30/0000Z 16.5N 105.8W   65 KT  75 MPH
 36H  30/1200Z 17.9N 107.0W   75 KT  85 MPH
 48H  01/0000Z 18.9N 107.8W   80 KT  90 MPH
 60H  01/1200Z 19.5N 108.5W   85 KT 100 MPH
 72H  02/0000Z 19.9N 109.1W   85 KT 100 MPH
 96H  03/0000Z 20.4N 110.1W   80 KT  90 MPH
120H  04/0000Z 20.9N 111.4W   80 KT  90 MPH

$$
Forecaster Reinhart