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Tropical Depression SIX-E

Tropical Depression Six-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP062020
300 PM MDT Mon Jul 13 2020

The small disturbance and intermittent low pressure system that the 
NHC has been tracking for the past few days has finally developed a 
well-defined, closed surface circulation based on 1639Z ASCAT-B 
surface wind vector ambiguity data, and the system is thus being 
classified as Tropical Depression Six-E. Deep convection developed 
overnight and this morning, which helped to spin up a low-level 
center near and just inside of the northeastern portion of the 
convective cloud canopy. In addition, the forward speed has also 
decreased from 20 kt down to 14 kt, which has also likely helped to 
close off the circulation on the south side. The ASCAT scatterometer 
wind data data supported an intensity of at least 30 kt, and this is 
consistent with 18Z Dvorak satellite classifications of T2.0/30 kt 
from both TAFB and SAB.

The initial motion estimate is 270/14 kt based on conventional, 
microwave, and scatterometer satellite fix data over the past 12 
hours. The small cyclone is expected to be steered generally 
westward at about the same forward speed for the next few days due 
to a strong subtropical ridge situated to the north of the 
depression. By 96 h, the system is forecast to degenerate into an 
open wave. The NHC official forecast track lies close to the tightly 
packed simple consensus models, which is a just a little south of 
the NOAA corrected-consensus model, HCCA.

The current northerly vertical wind shear of about 15 kt affecting 
the depression is forecast to decrease to below 10 kt in 12-18 
hours, and remain that way until the 48-h period. This should allow 
for some slight strengthening to occur during the next 36 hours or 
so. By 48 hours and beyond, the cyclone will be moving over sub-26 
deg C sea-surface temperatures and the shear is forecast to become 
westerly to northwesterly at near 20 kt. The combination of these 
two negative factors should induce significant weakening of the 
small tropical cyclone, resulting in degeneration to a remnant low 
by 72 h and dissipation by 96 hours. The official intensity forecast 
closely follows the IVCN intensity consensus model.
INIT  13/2100Z 16.6N 112.6W   30 KT  35 MPH
 12H  14/0600Z 16.7N 114.9W   35 KT  40 MPH
 24H  14/1800Z 16.8N 117.8W   35 KT  40 MPH
 36H  15/0600Z 16.8N 120.6W   35 KT  40 MPH
 48H  15/1800Z 16.8N 124.2W   30 KT  35 MPH
 60H  16/0600Z 16.6N 127.9W   30 KT  35 MPH
 72H  16/1800Z 16.5N 131.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  17/1800Z...DISSIPATED
Forecaster Stewart