je.st
news
Hurricane Delta Forecast Discussion Number 17
2020-10-08 23:00:24| National Hurricane Center (Atlantic)
Issued at 400 PM CDT Thu Oct 08 2020 000 WTNT41 KNHC 082100 TCDAT1 Hurricane Delta Discussion Number 17 NWS National Hurricane Center Miami FL AL262020 400 PM CDT Thu Oct 08 2020 Delta is strengthening. In satellite imagery, an eye is now seen in the cold cloud tops of the central dense overcast. On the aircraft side, just received reports from an Air Force Reserve Hurricane Hunter aircraft included 700-mb flight-level winds of 119 kt, SFMR winds estimates near 90 kt, and a central pressure of 959 mb inside a 30 n mi wide eye. A blend of the flight-level and SFMR wind estimates give an initial intensity of 100 kt, and Delta is again a major hurricane. The initial motion is now northwestward or 320/10 kt. There is no change to the track forecast philosophy and little change to the track forecast from the previous advisory. During the next 12-24 h, Delta should turn to the north between a mid- to upper-level ridge over the Florida Peninsula and eastern Gulf of Mexico and a mid- to upper-level level trough over the U.S. Southern Plains. This should be followed by a north-northeastward motion that is expected to bring the center near or over the northern Gulf coast, most likely in southwestern Louisiana, in about 30 h. After landfall, the cyclone should move northeastward through the Lower Mississippi and Tennessee Valleys along the southern edge of the mid-latitude westerlies until it dissipates. The track guidance remains very tightly clustered in terms of direction, and the new forecast track is near the various consensus models. Shear, sea surface temperature, and moisture conditions appear favorable for strengthening during the next 12 h or so, and based on this additional intensification is expected tonight. A short period of rapid intensification remains possible given current trends, although the various rapid intensification indices are not enthusiastic about the possibilities of this, After 12 h, the global models again forecast strong southwesterly shear developing over the hurricane before landfall, and based on this some weakening is forecast. Rapid weakening is expected after landfall. The system is expected to weaken to a depression no later than 60 h and degenerate to a remnant low by 72 h, with dissipation following shortly thereafter. The intensity forecast lies at or above the upper edge of the intensity guidance. Recent scatterometer data indicates that Delta is growing in size as it approaches the Louisiana coast. The NHC wind radii forecast again follows a combination of the data and the forecasts from global and hurricane regional models. Key Messages: 1. Life-threatening storm surge is expected near and east of where Delta makes landfall Friday, and a Storm Surge Warning is in effect from High Island, Texas, to Ocean Springs, Mississippi. The highest inundation of 7 to 11 feet is expected somewhere between Rockefeller Wildlife Refuge and Morgan City, Louisiana. Residents in the warning area should promptly follow advice given by local officials. The storm surge risk remains high despite the forecast decrease in intensity before landfall since Delta is expected to grow in size. 2. Hurricane-force winds are expected Friday afternoon and evening somewhere within the Hurricane Warning area between High Island, Texas, and Morgan City, Louisiana. Hurricane force winds will also spread inland across portions of southern Louisiana near the path of Deltas center Friday evening and Friday night. 3. Heavy rainfall will lead to significant flash flooding and minor to major river flooding in parts of Louisiana Friday and Saturday. Additional flooding is expected across portions of the central Gulf Coast into the Lower Mississippi Valley. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 24.8N 93.4W 100 KT 115 MPH 12H 09/0600Z 26.3N 93.9W 110 KT 125 MPH 24H 09/1800Z 28.6N 93.5W 105 KT 120 MPH 36H 10/0600Z 31.0N 92.5W 65 KT 75 MPH...INLAND 48H 10/1800Z 32.9N 91.1W 40 KT 45 MPH...INLAND 60H 11/0600Z 34.3N 89.2W 30 KT 35 MPH...INLAND 72H 11/1800Z 35.8N 87.2W 20 KT 25 MPH...POST-TROP/INLAND 96H 12/1800Z...DISSIPATED $$ Forecaster Beven
Tags: number
discussion
delta
forecast
Category:Transportation and Logistics