Eastern Pacific Basin Tropical Cyclones

Tropical Depression Eighteen-E Forecast Discussion


000
WTPZ43 KNHC 060900
TCDEP3

Tropical Depression Eighteen-E Discussion Number   8
NWS National Hurricane Center Miami FL       EP182021
400 AM CDT Sat Nov 06 2021

The depression's associated deep convection remains poorly 
organized, and recent ASCAT scatterometer surface wind data indicate 
that the inner-core wind field is elongated northeast to southwest. 
In addition, the highest ASCAT wind speeds noted were 25-27 kt. 
Based on that ASCAT data, the intensity has been lowered to 25 kt, 
which is consistent the T1.0 and T1.5 satellite classifications from 
TAFB and SAB, respectively.

The depression is moving just south of due west, or 260/12 kt. A 
westward to west-northwestward motion along the southern periphery 
of a sprawling deep-layer ridge entrenched to the north and 
northwest of the cyclone is forecast to continue for the next 5 
days. The new NHC forecast track is similar to the previous advisory 
track, and lies near or a tad south of the tightly-packed consensus 
track models.

Entrainment of dry air mid- and upper-level air from the south is 
expected to prevent any significant organization of deep convection 
from occuring for the next 24 h or so despite the very low vertical 
shear conditions of around 5 kt. Thereafter, the combination of low 
shear, a slightly more moist environment, and warmer sea-surface 
temperatures of 27.5-28C should allow for some modest strengthening 
to occur on days 2-5. The latest NHC official intensity forecast is 
the same as the the previous forecast, and closely follows an 
average of the various simple- and corrected intensity consensus 
models.


FORECAST POSITIONS AND MAX WINDS

INIT  06/0900Z  8.6N  95.5W   25 KT  30 MPH
 12H  06/1800Z  8.4N  97.1W   25 KT  30 MPH
 24H  07/0600Z  8.2N  99.4W   25 KT  30 MPH
 36H  07/1800Z  8.3N 101.8W   30 KT  35 MPH
 48H  08/0600Z  8.9N 104.1W   30 KT  35 MPH
 60H  08/1800Z  9.3N 106.6W   30 KT  35 MPH
 72H  09/0600Z  9.6N 109.0W   35 KT  40 MPH
 96H  10/0600Z 10.3N 113.9W   40 KT  45 MPH
120H  11/0600Z 10.6N 119.0W   45 KT  50 MPH

$$
Forecaster Stewart



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