ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM 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 NNNN