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Tropical Storm Lidia Discussion Number  16
NWS National Hurricane Center Miami FL       EP152023
900 PM MDT Fri Oct 06 2023
 
Moderate easterly deep-layer shear continues over Lidia this
evening. Earlier visible satellite images along with AMSR2 and SSMIS
passive microwave data indicate the low-level center lies near the
northeastern edge of a large convective mass. The cyclone continues
to produce very deep convection, with infrared cloud tops as cold as
-85 deg C. But, the tilted vertical structure signifies that Lidia
has likely not strengthened, and the initial intensity is held at 60
kt. This is once again in best agreement with the UW-CIMSS SATCON,
D-PRINT, and D-MINT estimates. The ASCAT-B and -C overpasses
expected over Lidia later tonight should help to better assess the
low-level structure and refine the wind radii values.
 
Lidia is moving slowly westward at 275/5 kt. In the near term,
models are in good agreement that the storm will gradually turn
northwestward and northward during the next couple of days. By early
next week, a developing shortwave trough over the eastern Pacific is
forecast to cause Lidia to accelerate northeastward and move toward
the southwestern or west-central coast of Mexico. There is increased
spread in the guidance beyond 72 h, particularly in the along-track
direction. The NHC track forecast has been shifted slightly to the
right of the previous prediction, bringing it closer to the latest
consensus aids. The day 5 forecast position is just inland over
western Mexico, but note uncertainty is high as the GFS and ECMWF
are over 24 h apart in terms of when Lidia might reach the coast.
 
Although Lidia is currently moving over very warm SSTs, the easterly
shear is forecast to persist over the next couple of days. Thus,
only small intensity fluctuations are forecast through the weekend,
and Lidia could hover near or just below hurricane intensity during
this period. The global and regional models suggest there is a brief
window where Lidia could move under an upper-level ridge in about 3
days, providing a brief respite from the shear and allowing the
cyclone to become better organized. There is also some potential for
positive trough interaction thereafter, despite the increased
southwesterly shear forecast at 96-120 h. The spread in the
intensity guidance grows substantially beyond day 3. The HAFS-A and
-B models show Lidia peaking as a major hurricane, while the GFS
shows a hurricane and other global and regional models keep the
system a tropical storm. Overall, there is enough model evidence to
warrant showing slight strengthening later in the period, but the
longer-range intensity forecast is highly uncertain and future
adjustments may be required.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/0300Z 16.4N 111.6W   60 KT  70 MPH
 12H  07/1200Z 16.5N 112.3W   65 KT  75 MPH
 24H  08/0000Z 16.8N 113.0W   65 KT  75 MPH
 36H  08/1200Z 17.3N 113.3W   60 KT  70 MPH
 48H  09/0000Z 17.9N 113.2W   60 KT  70 MPH
 60H  09/1200Z 18.5N 112.6W   60 KT  70 MPH
 72H  10/0000Z 19.0N 111.5W   65 KT  75 MPH
 96H  11/0000Z 20.5N 108.5W   60 KT  70 MPH
120H  12/0000Z 22.5N 105.5W   55 KT  65 MPH...INLAND
 
$$
Forecaster Reinhart
 
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