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Tropical Storm Lidia Discussion Number   2
NWS National Hurricane Center Miami FL       EP152023
900 AM MDT Tue Oct 03 2023
 
Lidia continues to have bursts of deep convection this morning, 
with cold cloud tops to -80 degrees Celsius. An earlier AMSR2 
microwave pass depicted a curved banding feature developing to the 
west and north of the low-level center, as Lidia's convection 
continues to organize. A blend of subjective and objective  
satellite intensity estimates are around 35 kt, which is in good 
agreement with the earlier scatterometer passes from this morning. 
Therefore, the initial intensity for this advisory remains 35 kt.
 
The system is moving west-northwest at 300/8 kt, around the southern 
edge of a mid-level ridge located over Mexico. A mid- to 
upper-level trough to the northwest will begin to weaken the ridge 
allowing Lidia to move more northwest to north-northwest the next 
few days.  The guidance envelope is in fairly good agreement with 
this general motion the next 48 hours or so. Beyond day 2, there is 
a little more uncertainty in the forecast as models differ on the 
timing of the mid-level ridge building back in as the trough lifts 
out of the area. The GFS and ECMWF turn the system more westward as 
the ridge strengthens, compared to some of the hurricane regional 
models, like HAFS-A and HAFS-B, which continue a more northward 
motion. The NHC forecast is closer to the ECMWF/GFS solutions 
through the end of the forecast period, with a slow turn westward.

Lidia is currently dealing with some moderate easterly vertical wind 
shear. The ECMWF/GFS SHIPS guidance depicts that moderate shear will 
remain over the system throughout the forecast period. The system 
will remain over fairly warm sea-surface temperatures near 30 C, and 
a favorable upper-level wind pattern with divergence aloft. RI 
parameters are slightly lower in the short-term compared to the 
previous cycle. However, the ECMWF-SHIPS has a 55 percent chance of 
a 65-kt increase in 72 hours. While this will not be explicitly 
forecast we will continue to monitor these parameters and trends in 
subsequent forecasts. The NHC intensity forecast is fairly similar 
to the previous showing gradual intensification throughout the 
period, and lies near the IVCN simple consensus aid.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/1500Z 12.3N 107.6W   35 KT  40 MPH
 12H  04/0000Z 13.1N 108.5W   40 KT  45 MPH
 24H  04/1200Z 14.0N 109.3W   45 KT  50 MPH
 36H  05/0000Z 14.8N 109.7W   50 KT  60 MPH
 48H  05/1200Z 15.4N 110.0W   55 KT  65 MPH
 60H  06/0000Z 15.9N 110.4W   60 KT  70 MPH
 72H  06/1200Z 16.0N 111.0W   65 KT  75 MPH
 96H  07/1200Z 15.9N 112.3W   65 KT  75 MPH
120H  08/1200Z 15.9N 114.0W   65 KT  75 MPH
 
$$
Forecaster Kelly/Stevenson
 
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