Tropical Cyclone Discussion

385
WTPZ43 KNHC 022031
TCDEP3
 
Hurricane Rachel Discussion Number  23
NWS National Hurricane Center Miami FL       EP182026
200 PM MST Fri Oct 02 2026

The structure of Rachel has not changed appreciably since the 
previous advisory.  A ragged, cloud-filled eye can still be seen on 
visible satellite imagery.  The cloud pattern can also be described 
as having a large central dense overcast or embedded center, with 
the deep convection spanning roughly 200 n mi in diameter.  The 
latest subjective intensity estimate from TAFB is T4.5/77 kt, and 
the latest objective estimates from UW-CIMSS range from about 77-99 
kt.  The initial intensity is lowered slightly to 90 kt for this 
advisory, as a compromise of the subjective and objective estimates.

The cyclone is still moving slowly westward at 265/4 kt and has made 
its closest approach Socorro Island, passing about 30 to 35 n mi 
north of the station, which recorded winds of 53 kt gusting to 74 kt 
and a minimum pressure 982.6 mb.  This data fits in nicely with a 
pair of recent ASCAT passes over Rachel from around 1700 UTC.  The 
previous operational radii didn't need much adjusting since the 
ASCAT passes showed very similar radii to what we were carrying.

This slow westward motion is expected to continue with a gradual 
increase in forward speed over the weekend and into early next week 
as a mid-level ridge builds to the north.  A gradual bend toward the 
west-northwest is forecast by Monday as the ridge begins to weaken.  
The track guidance remains in fair agreement on this scenario, 
although some differences remain in the timing of the increase in 
forward speed by early next week. The latest NHC track forecast is 
just a hair north of the previous prediction and lies near the HCCA 
and TVCN consensus aids.  The NHC forecast is still about 30 miles 
to the left (or south) of the Google DeepMind Ensemble Mean, 
especially from hour 24 to 96.

The hurricane's structure hasn't changed much in the past 6 hours, 
and the guidance hasn't changed much either on this cycle, so no 
major changes are made to the NHC intensity forecast.  Over the next 
36 hours, moderate northeasterly wind shear could affect Rachel 
some.  Sea-surface temperatures (SSTs) are forecast to decrease 
along the hurricane's path during that time from 29 to 27C as Rachel 
encounters the cold wake from Hurricane Polo.  Gradual weakening is 
forecast during this period.  After that time, sea-surface 
temperatures (SSTs) should increase slightly to 28C along Rachel's 
path as it moves out of Polo's cold wake, but the cyclone will be 
moving into a drier mid-level environment.  The competing factors 
are expected to lead to little change in strength during the 36- to 
72-hour period, and NHC continues to flatline Rachel at 70 kt during 
that time.  In 4-5 days, Rachel should cross the 26C SST isotherm 
while it reaches an even drier mid-level airmass, and the system is 
forecast to weaken to a tropical storm by the end of the forecast 
period.  The NHC intensity forecast lies toward the higher end of 
the guidance envelope.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/2100Z 19.3N 111.1W   90 KT 105 MPH
 12H  03/0600Z 19.4N 111.6W   80 KT  90 MPH
 24H  03/1800Z 19.7N 112.4W   75 KT  85 MPH
 36H  04/0600Z 20.0N 113.2W   70 KT  80 MPH
 48H  04/1800Z 20.2N 114.2W   70 KT  80 MPH
 60H  05/0600Z 20.3N 115.4W   70 KT  80 MPH
 72H  05/1800Z 20.5N 116.8W   70 KT  80 MPH
 96H  06/1800Z 21.0N 120.0W   65 KT  75 MPH
120H  07/1800Z 22.0N 123.3W   55 KT  65 MPH