690 WTPZ41 KNHC 020851 TCDEP1 Hurricane Orlene Discussion Number 15 NWS National Hurricane Center Miami FL EP162022 300 AM MDT Sun Oct 02 2022 Orlene has continued to strengthen rapidly over the past several hours. On GOES-17 satellite imagery, the system has a well-defined eye with a temperature near -4 deg C surrounded by very cold tops to near -80 deg C, particularly over the western eyewall. Based on objective T-numbers from UW-CIMSS, the current intensity estimate is raised to 115 kt. Subjective Dvorak estimates are somewhat lower, but these are constrained by the rules of the technique. Over the 15-h period from 1800 UTC yesterday to the time of this advisory, the intensity of the hurricane has increased by an estimated 40 kt. Orlene remains a small tropical cyclone, with its destructive core covering an area some 20 n mi in diameter. The system continues to exhibit strong upper-level outflow with an outflow jet noted over the northern part of the circulation. In the short term, environmental conditions are expected to be conducive for further strengthening, with moderate vertical shear prevailing for the next 12 hours or so. Thereafter, although thermodynamic factors should remain conducive, the global models show a substantial increase in southwesterly vertical shear over the hurricane. This is also suggested by water vapor imagery which depicts a broad upper-level trough north of 20N and west of the Baja California peninsula. Since Orlene is a small hurricane, it should be especially susceptible to the negative effects of the increasing shear. Therefore a weakening trend is predicted to begin after 12 hours. Nonetheless, given Orlene's recent strengthening , the official intensity forecast is above all of the model guidance. It is anticipated that the system will be at or near hurricane strength when it reaches the coast of mainland Mexico. After landfall, the cyclone will quickly weaken over the mountainous terrain. Orlene continues moving northward or at about 005/6 kt. During the next 48 hours or so, the hurricane should be steered by the flow between the mid/upper-level trough near Baja California and northwestern Mexico and a subtropical ridge to its east. A slight bend of the heading toward the north-northeast is likely later today. The official forecast track is very close to the previous NHC track, and is a little to the east of the dynamical model consensus. The GFS model is significantly farther to the right and faster than the other track guidance. Key Messages: 1. Hurricane conditions are expected in the Islas Marias tonight, with tropical storm conditions beginning later today. A Hurricane Warning is in effect for a portion of west-central mainland Mexico, where hurricane conditions are expected on Monday with tropical storm conditions beginning early Monday. Preparations to protect life and property should be rushed to completion. 2. Heavy rainfall from Orlene is expected to lead to flash flooding, as well as possible landslides in areas of rugged terrain of southwestern Mexico into Tuesday. FORECAST POSITIONS AND MAX WINDS INIT 02/0900Z 19.0N 106.8W 115 KT 130 MPH 12H 02/1800Z 19.7N 106.6W 125 KT 145 MPH 24H 03/0600Z 20.9N 106.3W 105 KT 120 MPH 36H 03/1800Z 22.0N 106.0W 85 KT 100 MPH 48H 04/0600Z 22.8N 105.7W 65 KT 75 MPH...INLAND 60H 04/1800Z 23.2N 105.4W 40 KT 45 MPH...INLAND 72H 05/0600Z...DISSIPATED $$ Forecaster Pasch