000 WTNT42 KNHC 200253 TCDAT2 Hurricane Fiona Discussion Number 23 NWS National Hurricane Center Miami FL AL072022 1100 PM EDT Mon Sep 19 2022 The satellite presentation of the hurricane has improved significantly this evening. The eye has warmed and become more distinct and the surrounding ring of deep convection has cooled and is more symmetric. More recently, the eye has become smaller in size and this has also been observed by both NOAA and Air Force Reserve Hurricane Hunter aircraft that have been sampling the storm this evening. The aircraft have reported that the eye has shrunk to around 10 n mi in diameter. The NOAA plane has measured a peak flight level wind of 104 kt at around 8000 ft, while the Air Force aircraft has reported a peak 700-mb flight-level wind of 93 kt. Peak SFMR winds of 94-96 kt have also been found, and these data support increasing the initial intensity to 95 kt. The hurricane's outflow is somewhat restricted over the western portion of the circulation owing to some moderate southwesterly shear of the storm. Although this shear is not forecast to abate much, the intensity guidance indicates that warm water and a moist atmosphere should allow for continued intensification during the next 24 to 48 hours. Given the recent improvement in structure, the updated NHC intensity forecast calls for a slightly faster rate of strengthening during the next 12 to 24 hours, and it is at the upper end of the intensity guidance. The official forecast shows Fiona becoming a major hurricane overnight, and brings the hurricane to category 4 status in a day or so. Eyewall replacement cycles are likely to cause some fluctuations in intensity in the 24-72 h time period. By day 4, the hurricane is forecast to interact with a strong mid-tropospheric trough, which will start the system's extratropical transition. The process is forecast to be complete by the end of the period, and Fiona is expected to remain a powerful extratropical cyclone through day 5. The initial motion estimate is 330/9 kt. There track forecast philosophy again remains the same as the previous few forecast cycles. The hurricane should gradually turn north while moving around the western periphery of a mid-level ridge. After 72 hours, Fiona is forecast to turn north-northeastward and accelerate as a strong mid-level trough nears the northeastern United States. The track guidance remains tightly clustered and the NHC forecast is similar to the previous advisory, near the middle of the guidance envelope. Key Messages: 1. Heavy rains from Fiona will continue across parts of Puerto Rico and across northern and eastern Dominican Republic through tonight. These rainfall amounts will continue to produce life-threatening and catastrophic flooding along with mudslides and landslides across Puerto Rico. Life-threatening flash and urban flooding is likely for eastern portions of the Dominican Republic. 2. Hurricane conditions are expected over the Turks and Caicos, with tropical storm conditions over the southeastern Bahamas, beginning late tonight or early Tuesday. 3. Interests in Bermuda should monitor the progress of Fiona. FORECAST POSITIONS AND MAX WINDS INIT 20/0300Z 20.6N 70.3W 95 KT 110 MPH 12H 20/1200Z 21.8N 71.0W 110 KT 125 MPH 24H 21/0000Z 23.3N 71.4W 115 KT 130 MPH 36H 21/1200Z 24.6N 71.4W 120 KT 140 MPH 48H 22/0000Z 26.3N 71.0W 120 KT 140 MPH 60H 22/1200Z 28.5N 69.9W 120 KT 140 MPH 72H 23/0000Z 31.1N 68.0W 115 KT 130 MPH 96H 24/0000Z 39.8N 60.7W 105 KT 120 MPH 120H 25/0000Z 49.7N 58.5W 65 KT 75 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown