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| #1197499 (Received by flhurricane at: 10:36 PM 09.Sep.2024) TCDAT1 Tropical Storm Francine Discussion Number 6 NWS National Hurricane Center Miami FL AL062024 1000 PM CDT Mon Sep 09 2024 After strengthening this afternoon, Francine`s intensity appears to have leveled off for now. Around 18Z today, microwave images indicated that the storm had a closed low-level eyewall and a relatively symmetric cloud pattern. However, an intrusion of dry air has caused the inner core convection to degrade. The Air Force and NOAA Hurricane Hunter aircraft have been investigating Francine this evening and have found that the maximum winds have changed little from earlier and remain around 55 kt. However, the minimum pressure reported from the aircraft has dropped to 992 mb, which could indicate that strengthening will resume soon. The outer rainbands to the west and northwest of the center are very near the coast of northeastern Mexico and extreme southern Texas, and there are likely tropical-storm-force winds in those bands. The storm has been moving slowly north-northwestward or 340 degrees at 4 kt. A mid-level ridge situated over the southeastern Gulf of Mexico should cause Francine to continue to move slowly northwestward to northward just off the coast of northeastern Mexico through Tuesday morning. By late Tuesday, a trough over Texas is expected to approach the system, and the stronger flow between the trough and the aforementioned ridge should cause a turn to the northeast with a pronounced increase in forward speed. This motion should take the cyclone to the Louisiana coast Wednesday afternoon or evening. The models are in fairly good agreement on this scenario, but there is a fair amount of along-track spread or differences in when the storm reaches the coast. The NHC track forecast is similar to the previous one and near the TVCN aid. Environmental conditions are forecast to remain quite favorable for strengthening along Francine`s path for the next 24 hours, with very warm ocean waters while remaining in a low wind shear environment. The SHIPS RII index for rapid intensification over the next 24 hours has decreased a little due to some dry air in the environment around Francine. The NHC intensity forecast is similar to the previous one, and lies near the high end of the intensity guidance suite. Just prior to landfall, Francine should encounter increasing west-southwesterly vertical wind shear, which will likely end the intensification trend. Rapid weakening is expected after the storm moves inland. An experimental cone graphic that includes inland Hurricane and Tropical Storm Watches and Warnings in the U.S. is now available on the NHC website. Due to the time needed to compile the inland watch and warning information, the experimental cone graphic will not be available as quickly as the operational cone. Once it is available, the experimental cone graphic can be found from a red weblink above the operational cone graphic at https://www.nhc.noaa.gov/graphics_at1.shtml?cone#contents. Users are encouraged to take the experimental product survey found below the experimental cone. KEY MESSAGES: 1. There is a danger of life-threatening storm surge for portions of the Upper Texas and Louisiana coastlines where a Storm Surge Warning is in effect. Residents in the warning area should follow advice, including evacuation orders, given by local officials. 2. Damaging and life-threatening hurricane-force winds are expected in portions of southern Louisiana Wednesday, where a Hurricane Warning is in effect. Preparations to protect life and property should be complete by Tuesday night since tropical storm conditions are expected to begin within this area early Wednesday. 3. Francine is expected to bring heavy rainfall and the risk of considerable flash flooding along the coast of northeast Mexico, the far lower and far upper Texas coasts, much of Louisiana, and Mississippi into Thursday morning. A risk of flash and urban flooding exists across portions of the Mid-South from Wednesday night into Friday morning. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 24.3N 96.2W 55 KT 65 MPH 12H 10/1200Z 24.9N 96.0W 65 KT 75 MPH 24H 11/0000Z 26.2N 95.2W 80 KT 90 MPH 36H 11/1200Z 27.9N 93.7W 85 KT 100 MPH 48H 12/0000Z 29.9N 92.2W 75 KT 85 MPH...INLAND 60H 12/1200Z 32.4N 90.9W 40 KT 45 MPH...INLAND 72H 13/0000Z 34.6N 90.6W 30 KT 35 MPH...POST-TROPICAL 96H 14/0000Z 36.6N 90.0W 20 KT 25 MPH...POST-TROPICAL 120H 15/0000Z...DISSIPATED $$ Forecaster Cangialosi/Hagen |
