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| #1020346 (Received by flhurricane at: 11:03 PM 07.Oct.2020) TCDAT1 Hurricane Delta Discussion Number 14 NWS National Hurricane Center Miami FL AL262020 1000 PM CDT Wed Oct 07 2020 Observations from an Air Force Reserve Unit Hurricane Hunter aircraft indicate that Delta is gradually strengthening while it moves over the open waters of the south-central Gulf of Mexico. Based on a blend of adjusted flight-level and SFMR wind measurements from the plane, the current intensity is set at 80 kt. The cloud pattern of the hurricane continues to become better organized on satellite images, with a growing Central Dense Overcast, and convective banding features becoming better defined, particularly over the northern semicircle of the circulation. Additional intensification is likely while Delta moves through a favorable environment during the next day or so, and the official forecast is fairly close to the corrected consensus guidance, HCCA. When the system moves into the northern Gulf, a decrease in oceanic heat content, drier mid-tropospheric air, and increased vertical shear should cause at least slow weakening. The NHC intensity forecast is above the numerical guidance in 36-48 hours. It should be noted that 1-2 day tropical cyclone intensity forecasts are subject to errors of around 1 Saffir-Simpson category. The global models show a further increase in the size of the hurricane while it moves into the northern Gulf. The official wind radii forecasts are based on a consensus of these model predictions. The latest center fixes from the Hurricane Hunters show a west-northwestward motion, at about 300/15 kt. Delta should turn toward the north-northwest and north over the next 36 hours or so while moving around the western periphery of a subtropical high pressure system centered over Florida. When the hurricane moves into the northern Gulf of Mexico on Friday, Delta should turn toward the north-northeast on the southeastern side of a mid-tropospheric shortwave over the southern United States. The official track forecast is close to both the simple and corrected dynamical model consensus predictions, TVCA and HCCA, respectively. These objective aids are in close agreement with one another. Based on the official forecast, it is time to issue storm surge and hurricane warnings for a portion of the northern Gulf of Mexico coast. Key Messages: 1. Delta is expected to grow in size as it approaches the northern Gulf Coast, where life-threatening storm surge and dangerous hurricane-force winds are likely beginning Friday, particularly for portions of the Louisiana coast. Storm Surge and Hurricane Warnings are in effect, and residents in these areas should follow advice given by local officials and rush preparedness actions to completion. 2. Flash, urban, small stream and minor to isolated moderate river flooding is likely Friday and Saturday from portions of the central Gulf Coast into portions of the Lower to Middle Mississippi Valley. As Delta moves farther inland, additional heavy rainfall is expected in the Ohio Valley and Mid Atlantic this weekend. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 22.5N 90.9W 80 KT 90 MPH 12H 08/1200Z 23.7N 92.2W 95 KT 110 MPH 24H 09/0000Z 25.4N 93.4W 105 KT 120 MPH 36H 09/1200Z 27.5N 93.5W 100 KT 115 MPH 48H 10/0000Z 30.0N 92.7W 85 KT 100 MPH 60H 10/1200Z 32.4N 91.5W 35 KT 40 MPH...INLAND 72H 11/0000Z 34.2N 89.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 12/0000Z 37.5N 85.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 13/0000Z...DISSIPATED $$ Forecaster Pasch |