ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM 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 NNNN