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Hurricane Laura Forecast Discussion Number 28
2020-08-26 22:51:32| National Hurricane Center (Atlantic)
Issued at 400 PM CDT Wed Aug 26 2020 000 WTNT43 KNHC 262051 TCDAT3 Hurricane Laura Discussion Number 28 NWS National Hurricane Center Miami FL AL132020 400 PM CDT Wed Aug 26 2020 Laura has continued to rapidly strengthen today with recent visible satellite imagery revealing a very distinct 25 nautical- mile-wide eye embedded in a symmetric central dense overcast. The upper-level outflow has also become well established in all quadrants. An Air Force Reserve hurricane hunter aircraft that is still investigating the hurricane has reported peak 700-mb flight-level winds of 136 kt and SFMR winds of 121 kt in the northeast eyewall. These data support an initial intensity of 125 kt, which is an increase of 55 kt over the past 24 hours. The minimum pressure has fallen to around 947 mb. The well-defined eye is now within range of the NWS Lake Charles WSR-88D radar, and hourly Tropical Cyclone Updates began at 1900 UTC (2 PM CDT) and will continue through landfall and beyond overnight. Laura still has about 12 hours remaining over the warm waters of the northwest Gulf of Mexico waters, but increasing southwesterly shear around the time of landfall and the possibility of an eyewall replacement could result in some fluctuations in intensity this evening, but Laura is expected to remain an extremely dangerous category 4 hurricane through landfall tonight. Although rapid weakening is expected on Thursday as Laura moves inland, the hurricane is expected to bring a swath of damaging winds well inland over western Louisiana and extreme eastern Texas. The cyclone or its remnants are forecast to move off Mid-Atlantic coast over the weekend and there remains some possibility that Laura will re-intensify as a tropical cyclone offshore of the United States east before it merges with a frontal boundary later in the forecast period. Recent satellite and aircraft fixes show that Laura is moving northwestward at about 13 kt. Laura is nearing the western extent of a mid-level ridge that is located over the southeastern United States. The hurricane should turn north-northwestward this evening and northward on Thursday between the ridge and a weak trough over the south-central United States. By Friday the cyclone should turn northeastward and then east-northeastward as it becomes embedded in the mid-latitude westerlies. The track model guidance continues to be in good agreement through 72, but there are some forward speed differences thereafter. The new NHC track is very close to the previous advisory and is near the middle of the guidance envelope. 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 this afternoon 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 26/2100Z 27.9N 92.8W 125 KT 145 MPH 12H 27/0600Z 29.7N 93.6W 130 KT 150 MPH 24H 27/1800Z 32.5N 93.5W 60 KT 70 MPH...INLAND 36H 28/0600Z 34.8N 92.7W 35 KT 40 MPH...INLAND 48H 28/1800Z 36.5N 90.1W 25 KT 30 MPH...INLAND 60H 29/0600Z 37.3N 85.6W 25 KT 30 MPH...INLAND 72H 29/1800Z 38.0N 79.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 30/1800Z 43.2N 64.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 31/1800Z 51.0N 49.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown
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