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Tropical Depression Three-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP032021
200 PM PDT Sat Jun 12 2021
 
The disturbance that has been tracked westward for the past several 
days across the open waters of the the tropical eastern Pacific has 
finally established a sufficiently well-defined low-level 
circulation to be designated as Tropical Depression Three-E. 
Convection increased last night and began to consolidate, while 
satellite images and microwave data this morning indicated that 
there was evidence of a well-defined low developing. This was later 
confirmed by a pair of ASCAT overpasses. These overpasses showed a 
compact radius of maximum winds. And, although the ASCAT-A data 
had a few vectors between 30-35 kt, these were not homogeneous and 
appeared unrepresentative of the system's intensity. In addition, 
the rather ragged satellite appearance and the Dvorak intensity 
estimate of 2.0 from SAB are suggestive that this system should be 
initialized as a 30-kt depression for this advisory. 

The environment surrounding the depression is moderately conducive 
for gradual strengthening, with SSTs of 27-28 degrees C, mid-level 
RH values between 50-60 percent, and vertical wind shear of about 
5-10 kt. These conditions are expected to continue for the next 2-3 
days. By 72 h, dry air and subsidence are expected to hinder any 
further intensification and should begin a weakening trend. By late 
in the forecast period, the system is forecast to cross the 26 
degree C isotherm, which should hasten the pace of weakening. The 
official intensity closely follows the HFIP corrected consensus 
HCCA, which shows the depression becoming a tropical storm tonight, 
and levels off its intensity by 48 h, followed by a weakening trend 
after 60 h.

A mid-level ridge to the north of the cyclone is steering it at a 
somewhat uncertain 275/08 kt. This ridge is forecast by nearly all 
of the models to weaken over the next couple of days, leaving the 
depression in a region of very weak steering currents through 
early next week. A mid-upper level trough digging southward to the 
northwest of the cyclone should induce a northerly component of 
motion along with an increase in forward speed by midweek. As 
said, there is good agreement on the pattern, however, the models 
vary greatly on how abruptly they slow the system. This is resulting 
in a track model spread of about 300 n mi by 72 h. The NHC track 
forecast tries to split the difference by closely following the TVCE 
and TVCN consensus aids. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/2100Z 11.8N 123.6W   30 KT  35 MPH
 12H  13/0600Z 11.9N 124.5W   35 KT  40 MPH
 24H  13/1800Z 11.7N 125.5W   40 KT  45 MPH
 36H  14/0600Z 11.4N 126.1W   45 KT  50 MPH
 48H  14/1800Z 11.0N 126.5W   50 KT  60 MPH
 60H  15/0600Z 10.8N 126.7W   50 KT  60 MPH
 72H  15/1800Z 11.0N 126.9W   45 KT  50 MPH
 96H  16/1800Z 12.5N 126.7W   40 KT  45 MPH
120H  17/1800Z 15.2N 126.1W   30 KT  35 MPH
 
$$
Forecaster Latto
 
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