Eastern Pacific Basin Tropical Cyclones

Tropical Depression Seven-E Forecast Discussion


000
WTPZ42 KNHC 260856 CCA
TCDEP2

Tropical Depression Seven-E Discussion Number   1...Corrected
NWS National Hurricane Center Miami FL       EP072022
400 AM CDT Tue Jul 26 2022

Conventional satellite imagery shows that deep convection associated 
with the low pressure area south of southern Mexico has continued 
to increase and become better organized.  An earlier SSMIS 
microwave overpass revealed an improved low-level structure, 
although most of the deep convection was located over the western 
portion of the system due to moderate easterly shear.  A couple of 
scatterometer overpasses between 0330 and 0500 UTC showed that the 
circulation had become much better defined and the system had peak 
winds around 30 kt.  Subjective Dvorak T-numbers from SAB and TAFB 
have also increased to T2.0, and based on all the above data, 
advisories are being initiated on Tropical Depression Seven-E.  The 
initial wind speed is set at 30 kt, in agreement with both the 
ASCAT data and the subjective Dvorak estimates. 

Moderate easterly shear is forecast to plague the system over the 
next 24 to 48 hours, however most of the intensity guidance 
suggests gradual strengthening will occur during that time.  The 
official forecast follows suit and calls for the depression to 
become a tropical storm later today or tonight. After 48 hours, the 
shear is expected to abate while the system is over SSTs of 28-29C 
and within a moist low- to mid-level environment.  Those conditions 
favor a faster rate of strengthening, and this is reflected in the 
NHC forecast which shows the system becoming a hurricane in about 72 
hours.  The intensity forecast is in good agreement with the HCCA 
and IVCN consensus aids and is also supported by the global model 
guidance which depicts more significant deepening in 2-3 days. 

The initial motion estimate is a somewhat uncertain 280/10 kt. The 
cyclone is expected to continue westward for the next few days while 
it is steered by a subtropical ridge that extends westward from 
northern Mexico.  After that time, the GFS and ECMWF models develop 
a slight weakness in the ridge off the coast of Baja California 
which allows the system to turn west-northwestward. The UKMET 
depicts a stronger ridge and a more westward track than the 
remainder of the guidance and its ensemble mean.  As a result, the 
official forecast is closer to a blend of the GFS and ECMWF models, 
and a bit north and east of the TVCE multi-model consensus. 


FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 11.4N 101.8W   30 KT  35 MPH
 12H  26/1800Z 11.8N 103.6W   35 KT  40 MPH
 24H  27/0600Z 12.1N 105.6W   40 KT  45 MPH
 36H  27/1800Z 12.2N 107.4W   45 KT  50 MPH
 48H  28/0600Z 12.5N 109.1W   50 KT  60 MPH
 60H  28/1800Z 12.8N 110.8W   60 KT  70 MPH
 72H  29/0600Z 13.3N 112.6W   70 KT  80 MPH
 96H  30/0600Z 14.9N 116.2W   80 KT  90 MPH
120H  31/0600Z 17.5N 119.7W   80 KT  90 MPH

$$
Forecaster Brown



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