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#983744 (Received by flhurricane at: 4:39 PM 23.Sep.2019) TCDAT3 Tropical Storm Lorenzo Discussion Number 4 NWS National Hurricane Center Miami FL AL132019 500 PM AST Mon Sep 23 2019 Lorenzo is steadily getting better organized. Visible imagery before sunset showed that the tropical storm has developed extensive banding that wraps about 3/4 of the way around the circulation. An 1836 SSMIS overpass also shows this banding, but indicated that the tropical storm has not developed a tight inner core. Satellite intensity estimates range from 35 to 47 kt, and the intensity of the system has been increased to 40 kt. All indications are that Lorenzo is in a favorable environment for strengthening, and all of the guidance continues to forecast that it will become a hurricane during the next few days, perhaps as soon as tomorrow. In fact, the SHIPS Rapid Intensification Index shows a 45 percent chance of a 25 kt or greater increase in Lorenzo`s winds during the next 24 hours. Since the tropical storm doesn`t have a tight inner-core yet, the NHC forecast isn`t quite as bullish, but still shows steady strengthening, and Lorenzo could become a major hurricane later this week. The tropical storm is moving steadily westward with an initial motion of 275/14. The new NHC track forecast is essentially just an update of the previous one, and no substantial changes were made. Lorenzo will likely move generally westward to west-northwestward at a similar forward speed for the next few days, before turning northwestward over the weekend. The global models are in very good agreement on this scenario, but do differ on how soon Lorenzo will turn northwestward. The NHC forecast is based primarily on HCCA, and is on the left side of the guidance envelope. This is also closer to the ECMWF and UKMET forecasts which delay the start of Lorenzo`s recurvature a little more than the GFS and its derived models. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 11.3N 25.5W 40 KT 45 MPH 12H 24/0600Z 11.7N 27.5W 50 KT 60 MPH 24H 24/1800Z 12.4N 30.2W 60 KT 70 MPH 36H 25/0600Z 13.1N 33.0W 70 KT 80 MPH 48H 25/1800Z 13.6N 35.7W 75 KT 85 MPH 72H 26/1800Z 15.4N 40.7W 85 KT 100 MPH 96H 27/1800Z 18.3N 43.8W 95 KT 110 MPH 120H 28/1800Z 21.5N 46.5W 100 KT 115 MPH $$ Forecaster Zelinsky |