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Hurricane Hanna Forecast Discussion Number 12
2020-07-25 22:59:37| National Hurricane Center (Atlantic)
Issued at 400 PM CDT Sat Jul 25 2020 000 WTNT43 KNHC 252059 TCDAT3 Hurricane Hanna Discussion Number 12 NWS National Hurricane Center Miami FL AL082020 400 PM CDT Sat Jul 25 2020 NOAA Doppler weather radar data from Brownsville and Corpus Christi, Texas, along with reconnaissance data from the Air Force Hurricane Hunters indicate that Hanna has continued to strengthen this afternoon. A 30-nmi-wide eye remains distinct in the radar data, and dropsonde and 700-mb flight-level-level height data from the aircraft indicate that the central pressure has decreased to 973 mb. The aircraft measured a peak 700-mb flight-level wind speed of 86 kt on its last outbound leg, which equates to about 77 kt at the surface. Coincident with the flight-level wind data were SFMR surface wind speeds of 80 kt. In addition, Doppler velocity values have been averaging close to 100 kt between 5000-6000 ft in the northern and northeastern eyewall, which converts to 80-kt surface wind speed estimates. Based on these data, the initial intensity has been increased to 80 kt. No further strengthening is anticipated before the center of Hanna's eye makes landfall along the south Texas coast in a few hours. Doppler radar and aircraft reconnaissance fixes indicate that Hanna has finally made the much anticipated turn toward the west-southwest, now showing an initial motion of 255/07 kt. A west-southwestward motion is expected to continue for the next 48 hours, which will take Hanna well inland over south Texas, followed by eventual dissipation in about 48 h over over the mountains of northeastern Mexico. The new NHC track forecast remains unchanged from the previous advisory, and lies near the center of the tightly packed consensus models. Key Messages 1. Life-threatening storm surge will continue along portions of the Texas coast from Port Mansfield to Sargent, where a Storm Surge Warning is in effect. Residents in these locations should follow advice given by local emergency officials. 2. Hurricane conditions will continue within the Hurricane Warning area along the Texas coast through this evening. Strong winds will also spread inland across portions of South Texas where Tropical Storm and Hurricane Warnings are in effect. 3. Hanna is expected to produce heavy rains across portions of southern Texas and northeastern Mexico. These rains will result in life-threatening flash flooding and isolated minor to moderate river flooding. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 26.8N 97.2W 80 KT 90 MPH 12H 26/0600Z 26.7N 98.4W 50 KT 60 MPH...INLAND 24H 26/1800Z 26.0N 100.0W 30 KT 35 MPH...INLAND 36H 27/0600Z 25.5N 101.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 48H 27/1800Z...DISSIPATED INLAND $$ Forecaster Stewart
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