953 WTPZ41 KNHC 010834 TCDEP1 Tropical Storm Orlene Discussion Number 10 NWS National Hurricane Center Miami FL EP162022 300 AM MDT Sat Oct 01 2022 Orlene has changed little in organization overnight. Recent microwave satellite imagery revealed Orlene is trying to maintain an inner core despite some dry air attempting to wrap in from its east. Scatterometer data indicated that the low-level center was slightly to the southeast of what was previously estimated. These data suggest that the cyclone may be feeling the affects of some southeasterly shear, possibly caused by flow around the ridge to its east. The initial intensity remains unchanged at 55 kt and is based off a blend of the latest Dvorak intensity estimates from SAB and the UW-CIMSS ADT. The storm has about 36 h left to take advantage of the relatively low vertical wind shear and moist thermodynamic environment. After 36 h, increasing southwesterly shear should cause Orlene to steadily weaken before reaching the coast of mainland Mexico early next week. The cyclone is then expected to dissipate shortly after moving inland. The overall model guidance continues to back off on the peak intensity of Orlene, likely due to the fact the cyclone has not been able to strengthen as quickly as expected over the past day or so. The NHC intensity forecast is slightly lower than the previous one, and is on the high end of the guidance. Orlene is moving slowly northward, at only 4 kt, to the west of a mid-level ridge. By tonight, the cyclone should turn north-northeastward in the flow between the ridge and an upper-level trough over northwestern Mexico and the northern Baja California peninsula. This north-northeastward motion is forecast to continue until Orlene dissipates over mainland Mexico. The latest NHC track forecast was nudged just east of the previous one, mainly due to the slight southeastward adjustment of the initial position. Based on the the forecast track, intensity, and wind radii, Hurricane or Tropical Storm Warnings will likely be required for portions of the Hurricane Watch area later today. Key Messages: 1. Hurricane conditions are possible in the Islas Marias Sunday night, with tropical storm conditions beginning late Sunday. Tropical storm conditions are expected within the tropical storm warning area along the west-central coast of Mexico on Sunday. Tropical storm conditions are possible over other portions of southwestern and west-central Mexico in the tropical storm watch area tonight or Sunday. 2. Heavy rainfall from Orlene is expected to lead to flash flooding, as well as possible landslides in areas of rugged terrain of Southwest Mexico into Monday evening. FORECAST POSITIONS AND MAX WINDS INIT 01/0900Z 17.2N 107.0W 55 KT 65 MPH 12H 01/1800Z 17.9N 106.9W 65 KT 75 MPH 24H 02/0600Z 18.9N 106.8W 75 KT 85 MPH 36H 02/1800Z 20.0N 106.5W 80 KT 90 MPH 48H 03/0600Z 21.2N 106.2W 70 KT 80 MPH 60H 03/1800Z 22.5N 105.9W 60 KT 70 MPH 72H 04/0600Z 23.7N 105.6W 30 KT 35 MPH...INLAND 96H 05/0600Z...DISSIPATED $$ Forecaster Latto