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Tropical Depression Fifteen-E Discussion Number   2
NWS National Hurricane Center Miami FL       EP152021
900 PM MDT Tue Sep 07 2021

Satellite imagery indicates that Tropical Depression Fifteen-E has 
changed little in organization during the past several hours.  
While the system is producing good convective banding in the 
eastern semicircle, the convection near the center is currently 
poorly organized, and there is no evidence that the inner core has 
consolidated.  Thus, the initial intensity remains 30 kt based 
mainly on continuity from the previous advisory.  A combination of 
conventional and 37 GHz microwave satellite imagery suggests that 
the center is farther east than previously thought, so the new 
initial position is about a half degree east of the previous 
advisory position.

The initial motion is a somewhat uncertain 300/5. A large mid-level 
anticyclone is located over the southwestern United States with a 
ridge extending southeastward across Mexico.  The anticyclone 
should shift a little eastward during the next few days, with the 
ridge extending southward across Mexico.  This evolution should 
steer the tropical cyclone generally northwestward for the next 
several days, followed by a more westward motion as the cyclone 
weakens over cooler water and is steered by low-level easterly flow. 
The track guidance is in good agreement with this scenario, and the 
new forecast track is near the consensus models.  However, the 
more eastward initial position required an eastward shift to the 
forecast track.  It should be noted that some erratic motion is 
possible until the cyclone develops a better-defined inner core.

Conditions appear favorable for strengthening until the system 
reaches the 26-deg-C SST isotherm in 60-72 h, with the main 
restraining factor being the current lack of internal organization.  
The intensity forecast has only minor adjustments from the previous 
forecast and calls for the depression to become a tropical storm in 
about 12 h and a hurricane in about 48 h.  Steady to rapid weakening 
is expected after 60-72 h due to the cooler water and dry air 
entrainment.

The more easterly initial position and the new forecast track 
require a Tropical Storm Watch for portions of Baja California Sur 
at this time.  Interests elsewhere in Baja California Sur should 
monitor the progress of this system.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/0300Z 18.2N 107.4W   30 KT  35 MPH
 12H  08/1200Z 18.6N 107.7W   35 KT  40 MPH
 24H  09/0000Z 19.4N 108.4W   45 KT  50 MPH
 36H  09/1200Z 20.4N 109.2W   55 KT  65 MPH
 48H  10/0000Z 21.7N 110.6W   65 KT  75 MPH
 60H  10/1200Z 22.8N 112.0W   65 KT  75 MPH
 72H  11/0000Z 23.7N 113.7W   55 KT  65 MPH
 96H  12/0000Z 24.5N 116.5W   40 KT  45 MPH
120H  13/0000Z 24.0N 119.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Beven
 
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