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Tropical Storm Lidia Discussion Number   9
NWS National Hurricane Center Miami FL       EP152023
300 AM MDT Thu Oct 05 2023
 
This morning's satellite presentation consists of a sheared cloud 
pattern with the surface center located near the eastern edge of the 
convective canopy.  Although the upper wind pattern is quite 
diffluent over Lidia, easterly shear continues to restrict the 
intensification rate.  The Dvorak satellite intensity estimates 
yield 45 kt from TAFB and SAB, and the initial intensity remains 
unchanged for this advisory. However, based on the 0411 UTC METOP-B 
scatterometer overpass, this could be generous.
 
The statistical GFS/ECMWF SHIPS guidance indicates that the moderate
deep-layer shear should persist over Lidia through the majority of
the forecast period.  Warm oceanic surface temperatures and a very
moist surrounding low- to mid-tropospheric thermodynamic environment
support modest strengthening over the next few days, and the NHC
forecast follows suit.  The official intensity forecast shows a 
peak intensity in 3 days and now indicates some weakening 
afterward due to an increase in shear magnitude (a combination of 
the cyclone's eastward trajectory and persistent easterly shear) and 
is based on a blend of the SHIPS and IVCN intensity guidance.
 
Lidia's is still moving northwestward, or 315/4 kt, and is being 
steered by a subtropical high located to the northeast over the 
west coast of central Mexico.  Around the 36-hour period, the ridge 
is forecast to build temporarily and turn Lidia westward with some 
further reduction in forward speed.  In 72 hours, the cyclone should 
gradually turn toward the northwest to north followed by a turn 
toward the northeast near the end of the period in response to an 
approaching sharp shortwave trough from the northwest, causing a 
break in the aforementioned subtropical ridge.  The NHC track 
forecast is based on a blend of the TVCE and HFIP HCCA consensus 
models and is shifted a little to the right of the previous 
advisory beyond day 3.  
 
Based on the METOP-B scatterometer swath, Lidia's wind radii were
increased slightly northeast through southwest.


 
FORECAST POSITIONS AND MAX WINDS
 
INIT  05/0900Z 15.7N 109.5W   45 KT  50 MPH
 12H  05/1800Z 15.9N 109.8W   45 KT  50 MPH
 24H  06/0600Z 16.1N 110.4W   50 KT  60 MPH
 36H  06/1800Z 16.0N 111.1W   50 KT  60 MPH
 48H  07/0600Z 15.9N 111.9W   55 KT  65 MPH
 60H  07/1800Z 16.0N 112.7W   60 KT  70 MPH
 72H  08/0600Z 16.2N 113.3W   60 KT  70 MPH
 96H  09/0600Z 17.1N 114.2W   55 KT  65 MPH
120H  10/0600Z 17.8N 113.5W   50 KT  60 MPH
 
$$
Forecaster Roberts
 
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