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Hurricane Laura Forecast Discussion Number 31
2020-08-27 16:48:40| National Hurricane Center (Atlantic)
Issued at 1000 AM CDT Thu Aug 27 2020 000 WTNT43 KNHC 271448 TCDAT3 Hurricane Laura Discussion Number 31 NWS National Hurricane Center Miami FL AL132020 1000 AM CDT Thu Aug 27 2020 Laura has continued to move inland over west-central Louisiana this morning. Satellite and radar imagery has shown a gradual filling of the eye, and a reduction in Doppler velocities in the northeastern eyewall. The initial intensity is set at 65 kt, based on a reduction of the Doppler velocities and the typical filling rate of inland hurricanes. The highest wind gusts at official observing sites within the past few hours has been at Alexandria, Louisiana, where a gust to 75 kt has been reported. The hurricane is moving slightly east of due north or 005/14 kt. A general northward motion should continue through this evening as the hurricane moves around the western portion of a mid-level ridge over the southeastern United States. Laura should turn northeastward overnight while it moves across Arkansas and becomes embedded within the mid-latitude westerlies. A faster east-northeastward motion is forecast by late Friday, which will bring Laura or its remnants across the central Appalachians and to the Mid-Atlantic states on Saturday. After that time, the system is expected to accelerate east-northeastward to northeastward over the western Atlantic. Laura will continue to rapidly weaken today while it moves farther inland. The cyclone will become a tropical storm this afternoon and is expected to weaken to a tropical depression tonight or early Friday. Although Laura is weakening, strong wind gusts are likely to spread over northern Louisiana and Arkansas into this evening. The UKMET and ECMWF models continue show the extratropical remnants of Laura strengthening somewhat over the western Atlantic, and the NHC forecast continues to depict the system as a gale-force low at days 3-5. An alternate scenario is for the system to be absorbed by a frontal boundary over the western Atlantic before the end of the forecast period. The extratropical portion of the forecast is based on guidance from the NOAA Ocean Prediction Center. Key Messages: 1. Dangerous storm surge will result in elevated water levels for the next few hours along the Gulf Coast from Sabine Pass, Texas, to Port Fourchon, Louisiana. In some areas where surge penetrated far inland, flood waters will not fully recede for several days. 2. Damaging winds will continue near the center of Laura over portions of northern Louisiana and Arkansas today and this evening. 3. Widespread flash flooding along small streams, urban areas, and roadways will continue across portions of Louisiana, Mississippi, and Arkansas. Additional rainfall 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, and Mid-Atlantic States Friday and Saturday. FORECAST POSITIONS AND MAX WINDS INIT 27/1500Z 31.9N 93.1W 65 KT 75 MPH 12H 28/0000Z 33.9N 92.7W 40 KT 45 MPH...INLAND 24H 28/1200Z 35.8N 91.2W 30 KT 35 MPH...INLAND 36H 29/0000Z 37.0N 87.7W 25 KT 30 MPH...INLAND 48H 29/1200Z 38.0N 82.1W 25 KT 30 MPH...POST-TROP/INLAND 60H 30/0000Z 38.7N 74.9W 30 KT 35 MPH...POST-TROP/INLAND 72H 30/1200Z 41.8N 66.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 31/1200Z 50.0N 53.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 01/1200Z 53.5N 43.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown
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Category:Transportation and Logistics