ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Tropical Storm Laura Discussion Number 15 NWS National Hurricane Center Miami FL AL132020 1100 AM EDT Sun Aug 23 2020 Laura continues to produce a large area of deep convection to the south and southeast of the estimated center location. The center has not been easy to locate this morning, but the low-cloud motions seen in GOES-16 one-minute visible imagery, along with surface observations, suggest that the center is just west of the west coast of Haiti. Data from a NOAA P-3 aircraft that has flown a tail-Doppler radar mission along the southern and northern coasts of Hispaniola this morning found maximum winds of 40-45 kt, so the initial intensity has been set at 45 kt. Little change in strength is expected during the next 36 hours while Laura moves near or over Cuba. When the center of Laura emerges over the Gulf of Mexico Monday night, the upper-level environment is expected to be conducive for strengthening, and once the circulation recovers from its trek over land, deepening is anticipated. Warm water and a very favorable upper-level wind pattern are expected to allow for steady intensification until Laura reaches the northern Gulf coast, and with landfall expected between the 72 and 96 h forecast points, the system could be somewhat stronger than explicitly indicated below. The NHC intensity forecast is a blend of the SHIPS and HFIP corrected consensus models. Although the center of Laura was been difficult to track while it passed over Hispaniola, the estimated motion is west-northwestward at about 18 kt. A strong deep-layer ridge over the western Atlantic should continue to steer Laura west-northwestward for the next couple of days. The track guidance has continued to nudge southward during the first 36 hours and the official forecast has been adjusted accordingly, taking the storm closer to the southern coast of Cuba. After that time, the ridge is forecast to build westward over the eastern Gulf of Mexico. This pattern should allow Laura to maintain a west-northwestward motion until it approaches the central Gulf, where a northwestward motion is expected to begin as the storm nears the western periphery of the ridge. The dynamical models have trended toward stronger ridging over the eastern Gulf, resulting in a westward shift in the guidance. The NHC track forecast has been moved westward at 72-96 hours, and lies between the GFS and ECMWF solutions. Users are reminded to not to focus on the exact details of the track forecast at the longer range as future adjustments will likely be required, and storm hazards will extend far from the center. Key Messages: 1. Tropical storm conditions are expected across portions of the Dominican Republic and Haiti, the Turks and Caicos, the southeastern Bahamas, and Cuba through Monday. Heavy rainfall is likely across these areas and could cause mudslides and life-threatening flash and urban flooding. 2. Tropical storm conditions are possible over the central Bahamas and Andros Island tonight and Monday, and in the Florida Keys on Monday. 3. While the details of the long-range track and intensity forecasts remain uncertain, Laura is forecast to strengthen over the Gulf of Mexico and there is an increasing risk of storm surge, rainfall, and wind impacts along portions of the U.S. Gulf Coast by the middle of the week. This could result in a prolonged period of hazardous weather for areas that are likely to be affected by Marco earlier in the week. Interests along the Gulf Coast should monitor the progress of Laura and Marco and updates to the forecast during the next few days. FORECAST POSITIONS AND MAX WINDS INIT 23/1500Z 19.2N 73.2W 45 KT 50 MPH 12H 24/0000Z 20.3N 76.0W 45 KT 50 MPH...INLAND 24H 24/1200Z 21.6N 79.9W 45 KT 50 MPH...NEAR CUBA 36H 25/0000Z 22.9N 83.2W 45 KT 50 MPH...INLAND 48H 25/1200Z 24.1N 86.2W 50 KT 60 MPH...OVER WATER 60H 26/0000Z 25.3N 88.9W 65 KT 75 MPH 72H 26/1200Z 26.8N 91.4W 80 KT 90 MPH 96H 27/1200Z 30.9N 94.0W 85 KT 100 MPH...INLAND 120H 28/1200Z 35.7N 92.8W 30 KT 35 MPH...INLAND $$ Forecaster Brown NNNN