000
WTPZ44 KNHC 180859
TCDEP4
 
Tropical Depression Four-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP042021
400 AM CDT Fri Jun 18 2021
 
Over the past 12 h convection has blossomed and has become better
organized over the broad low we have been monitoring a couple
hundred miles to the south of Acapulco, Mexico. Overnight
scatterometer-derived winds indicated that the system has acquired
a closed circulation with max winds in the northeast quadrant of 30
kt. The most recent 06z Dvorak satellite estimates were T1.5/25 kt
from TAFB and T2.0/30 kt from SAB. Since that time, deep cold
convection has continued to increase near the estimated center with
improved banding both the north and southwest quadrants. Due to
this continued improvement in satellite imagery, this system is
being upgraded to a 30-kt tropical depression this advisory.
 
Environmental conditions appear to be favorable for additional
intensification over the next 24-36 h as the storm reaches the
Mexican coastline with high mid-level relative humidity, only light
to moderate vertical wind shear, and very warm sea-surface
temperatures between 29 to 30 C. Thus the latest NHC forecast
indicates at least steady intensification, and TD4-E could become a
strong tropical storm as it approaches the Mexican coastline. The
NHC intensity forecast is in good agreement with the HFIP corrected
consensus (HCCA) guidance.
 
The estimated current motion of this depression is at 285/7 kt.
Currently the system is being steered by a narrow mid-level ridge
north of Mexico. However, this ridge is forecast to weaken and allow
the storm to gain latitude over the next 24-36 h. The latest NHC
forecast takes the depression to the coast of Mexico by late
Saturday. This forecast is in fairly good agreement with the latest
guidance and lies closest to the most recent ECMWF run, though
spread remains between models that keep the system just off the
Mexican coast like the UKMET versus the HWRF and GFS models which
take the storm further east and inland over Mexico sooner. Given
this track forecast, the government of Mexico has issued a tropical
storm watch for the coast of Mexico from Cabo Corrientes southward
to Lazaro Cardenas.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  18/0900Z 14.4N 101.6W   30 KT  35 MPH
 12H  18/1800Z 14.8N 102.5W   35 KT  40 MPH
 24H  19/0600Z 15.7N 103.5W   45 KT  50 MPH
 36H  19/1800Z 17.5N 104.5W   55 KT  65 MPH
 48H  20/0600Z 20.1N 105.2W   45 KT  50 MPH...INLAND
 60H  20/1800Z 23.1N 105.9W   35 KT  40 MPH...INLAND
 72H  21/0600Z 25.4N 106.5W   25 KT  30 MPH...POST-TROP/INLAND
 96H  22/0600Z...DISSIPATED
 
$$
Forecaster Papin/Blake