|
Show Selection: |
| #1014082 (Received by flhurricane at: 11:06 PM 26.Aug.2020) TCDAT3 Hurricane Laura Discussion Number 29 NWS National Hurricane Center Miami FL AL132020 1000 PM CDT Wed Aug 26 2020 Extremely dangerous Laura has the signature of a classic hurricane on satellite images, with a well-defined eye surrounded by very deep convection. There is little evidence of shear, and the upper-level outflow pattern is extremely well defined, while the cyclone is over sea surface temperatures near 30 deg C. Observations from both NOAA and Air Force Hurricane Hunter aircraft show that Laura continued to strengthen during the evening. Using a blend of adjusted flight-level and SFMR-observed surface winds, the intensity estimate is 130 kt for this advisory. Since there is now little time remaining for the system over water, no significant change in intensity is anticipated until the center crosses the coastline. Laura will weaken rapidly after it begins to move over land, but destructive winds should spread well inland, more than 100 miles, along its path. Later in the forecast period, the ECMWF and U.K. Met. Office global models indicate some baroclinic re-intensification as the remnants of Laura move off the U.S. East coast, and this is reflected in the NHC forecast. Laura has begun to turn northward as it moves around the western side of a subtropical high pressure area, and the initial motion is about 340/13 kt. The track forecast is essentially unchanged from the previous advisories. The cyclone should move through a weakness in the ridge and turn to the northeast over the next day or two. Then the system should accelerate toward the east-northeast while embedded in the westerlies. The official track forecast remains close to both the simple and the corrected dynamical model consensus predictions, TVCA and HCCA. Laura is a large hurricane, and users are reminded to not focus on the precise track forecast since wind, storm surge, and rainfall hazards extend far from the center. Key Messages: 1. Unsurvivable storm surge with large and destructive waves will cause catastrophic damage from Sea Rim State Park, Texas, to Intracoastal City, Louisiana, including Calcasieu and Sabine Lakes. This surge could penetrate up to 40 miles inland from the immediate coastline, and flood waters will not fully recede for several days after the storm. 2. Hurricane-force winds are expected tonight in portions of the hurricane warning area, with catastrophic wind damage expected where Laura`s eyewall moves onshore. Hurricane-force winds and widespread damaging wind gusts will spread well inland into portions of extreme eastern Texas and western Louisiana early Thursday. 3. Widespread flash flooding along small streams, urban areas, and roadways is expected to begin overnight tonight into Thursday from far eastern Texas into Louisiana and Arkansas. This will also lead to minor to moderate freshwater river flooding. The heavy rainfall threat and flash and urban flooding potential will spread northeastward into the middle-Mississippi, lower Ohio, and Tennessee Valleys Friday night and Saturday. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 29.0N 93.2W 130 KT 150 MPH 12H 27/1200Z 31.0N 93.7W 95 KT 110 MPH...INLAND 24H 28/0000Z 33.8N 92.9W 50 KT 60 MPH...INLAND 36H 28/1200Z 35.6N 91.5W 35 KT 40 MPH...INLAND 48H 29/0000Z 36.8N 88.2W 25 KT 30 MPH...INLAND 60H 29/1200Z 37.5N 82.7W 25 KT 30 MPH...POST-TROP/INLAND 72H 30/0000Z 38.5N 75.5W 30 KT 35 MPH...POST-TROP/EXTRATROP 96H 31/0000Z 45.0N 60.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 01/0000Z 52.0N 46.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch |