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Tropical Storm Lidia Discussion Number  19
NWS National Hurricane Center Miami FL       EP152023
300 PM MDT Sat Oct 07 2023
 
Recent partial ASCAT passes and infrared satellite imagery indicate
that the center of Lidia has been located well underneath the
large, cold convective canopy for the past several hours. This
suggests that the northeasterly to easterly shear may have
decreased slightly compared to yesterday. However, recent SSMIS and
GMI passes indicate that the structure has not improved much. The
recent ASCAT passes also suggest that the winds have not increased
yet. Despite subjective Dvorak estimates ranging from 65 to 77 kt
and objective estimates ranging from 51 to 63 kt, the intensity is
held at 55 kt for this advisory based on the ASCAT data.
 
There is not much change to the track forecast reasoning. The
microwave and ASCAT data indicate that Lidia has not made any
significant northward progress yet. The motion is estimated at 280/3
kt. A gradual turn to the north is expected to occur over the next
24 h, after which time, the cyclone is expected to begin interacting
with an approaching trough from the north. This interaction will
result in an acceleration early next week toward the northeast and
in the general direction of west-central Mexico. The NHC forecast is
similar to the previous forecast through 60 h, but shows a faster
northeastward motion around the time of landfall and after landfall,
and is in best agreement with the TVCE consensus aid. It should be
noted that there remains significant along-track spread in the
guidance, meaning that there is some uncertainty in the timing of
landfall.
 
Moderate easterly shear is likely to inhibit significant
intensification through early Sunday. However, the shear is expected
to briefly relax late Sunday through Monday night, as the cyclone
moves northward over warm sea-surface temperatures. Lidia is
therefore forecast to intensify to hurricane strength by Monday. It
should be noted that Lidia could intensify a bit more quickly than
forecast, considering the center is now well underneath the cold
convective canopy. As the storm approaches landfall in Mexico,
southwesterly shear is expected to increase, but this shear may not
have time to affect the cyclone much before it makes landfall.
Furthermore, it should be noted that the deterministic GFS global
model depicts very low central pressures, suggesting Lidia could
maintain hurricane intensity through landfall. Other reliable
statistical models and consensus aids are not as aggressive. The NHC
forecast is similar to the prior forecast, except it brings Lidia to
hurricane strength a bit sooner. Confidence in the intensity
forecast is below average. Interests in west-central Mexico should
remain attentive to forecast updates in the coming days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/2100Z 16.1N 112.5W   55 KT  65 MPH
 12H  08/0600Z 16.6N 112.7W   55 KT  65 MPH
 24H  08/1800Z 17.4N 112.8W   60 KT  70 MPH
 36H  09/0600Z 18.2N 112.5W   60 KT  70 MPH
 48H  09/1800Z 18.8N 111.6W   65 KT  75 MPH
 60H  10/0600Z 19.3N 110.0W   65 KT  75 MPH
 72H  10/1800Z 20.3N 107.7W   65 KT  75 MPH
 96H  11/1800Z 22.9N 103.3W   40 KT  45 MPH...INLAND
120H  12/1800Z...DISSIPATED
 
$$
Forecaster Hagen/Berg
 
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