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| #1020071 (Received by flhurricane at: 11:03 PM 05.Oct.2020) TCDAT1 Hurricane Delta Discussion Number 6 NWS National Hurricane Center Miami FL AL262020 1100 PM EDT Mon Oct 05 2020 A few hours ago, data from the NOAA Hurricane Hunters supported upgrading Delta to a hurricane. Very recent reports from the Air Force Hurricane Hunters, who are currently in Delta, support increasing the intensity a little more to 70 kt. The minimum pressure has also decreased a few mb from the NOAA mission, and is now estimated to be 977 mb. Delta has strengthened at a rapid rate of 40 kt since genesis occurred just 24 hours ago. The hurricane is quite compact with a developing tight inner core, and even the tropical-storm-force winds extend only up to 60 n mi or so from the center. After moving westward for much of the day, aircraft fixes from NOAA and the Air Force indicate that the hurricane has resumed a west-northwest motion, with the latest initial motion estimated to be 295/6 kt. Delta is expected to move to the northwest at a fairly quick pace on Tuesday and Wednesday as it moves in the flow between a subtropical high over the western Atlantic and Post-Tropical Cyclone Gamma over or near the Yucatan Peninsula. This motion should take Delta over or very near the northeastern portion of the Yucatan Peninsula by Tuesday night and over the southern Gulf of Mexico on Wednesday. After that time, the western part of the ridge is expected to slowly erode as a trough moves eastward across the south-central U.S. This change in the steering pattern should cause Delta to slow down and then turn northward toward the northern Gulf coast, and it will likely make landfall there in a little more than 4 days. The models are in fair agreement, and the NHC track forecast is only a touch to the west of the previous one. The hurricane has taken advantage of the near ideal conditions of low vertical wind shear, high amounts of moisture, and very warm 29-30 C SSTs. These favorable environmental conditions for the hurricane will persist for the next 2 or 3 days or so, and therefore, it seems reasonable to believe that rapid intensification will continue in the short term. Delta is expected to become a major hurricane in about 24 hours when it is near the Yuctan Peninsula. If Delta makes landfall on that landmass, it would likely temper the cyclone`s strength for a period of time. Beyond a few days, when Delta is forecast to approach the northern Gulf coast, there will likely be an increase in southwesterly wind shear. These less conducive upper-level winds and cooler shelf waters should end the strengthening trend prior to the U.S. landfall. The NHC intensity forecast is largely an update of the previous one and lies close to the HCCA and IVCN consensus models. Users are reminded to not focus on the details of the track or intensity forecasts, as the average 4-day track error is around 150 miles and the average 4-day intensity error is close to 15 mph. Key Messages: 1. Dangerous storm surge and hurricane conditions are expected within portions of the northern Yucatan Peninsula of Mexico beginning Tuesday night, and a Hurricane Warning is in effect. 2. Heavy rainfall will affect portions of Jamaica, the Cayman Islands, western Cuba and the northern Yucatan Peninsula during the next few days. This rainfall could lead to significant flash flooding and mudslides. 3. Tropical storm conditions are expected in portions of the Cayman Islands beginning early Tuesday, and a Tropical Storm Warning is in effect. 4. Delta is forecast to approach the northern Gulf Coast late this week as a hurricane. While there is large uncertainty in the track and intensity forecasts, there is an increasing risk of dangerous storm surge, wind, and rainfall hazards along the coast from Louisiana to the western Florida Panhandle beginning Thursday night or Friday. Residents in these areas should ensure they have their hurricane plan in place and monitor updates to the forecast of Delta. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 16.8N 80.3W 70 KT 80 MPH 12H 06/1200Z 18.1N 82.0W 85 KT 100 MPH 24H 07/0000Z 19.8N 84.6W 100 KT 115 MPH 36H 07/1200Z 21.5N 87.1W 105 KT 120 MPH...INLAND 48H 08/0000Z 23.0N 89.5W 105 KT 120 MPH 60H 08/1200Z 24.0N 90.8W 105 KT 120 MPH 72H 09/0000Z 25.2N 91.7W 100 KT 115 MPH 96H 10/0000Z 28.6N 91.2W 85 KT 100 MPH 120H 11/0000Z 33.6N 88.4W 35 KT 40 MPH...INLAND $$ Forecaster Cangialosi |