je.st
news
Tropical Storm Laura Forecast Discussion Number 21
2020-08-25 04:45:24| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT Mon Aug 24 2020 000 WTNT43 KNHC 250245 TCDAT3 Tropical Storm Laura Discussion Number 21 NWS National Hurricane Center Miami FL AL132020 1100 PM EDT Mon Aug 24 2020 Tropical Storm Laura made landfall on the Pinar del Rio province in western Cuba around 0000 UTC with maximum winds of about 55 kt. Around that time, a wind gust of 56 kt was reported in Havana. Since then the storm has moved across western Cuba and is now coming off the island and over the extreme southeastern Gulf of Mexico. Radar data from Cuba and satellite images indicate that the storm has become better organized with deep convection beginning to wrap around the center with persistent thunderstorms on the south side. Data from the NOAA and Air Force Hurricane Hunters indicate that the pressure has fallen to 996 mb and that the winds are around 55 kt. Laura continues to move fairly steadily to the west-northwest with the latest initial motion estimated to be 290/17 kt. The track forecast reasoning is generally unchanged from previous discussions. Laura should continue to move west-northwestward at about the same forward speed through Tuesday as it remains in the flow on the southwest side of the Atlantic subtropical ridge. By early Wednesday, Laura will likely slow down and turn northwestward and then northward as it moves into a break in the ridge, caused by a weak trough over the south-central U.S. This motion should cause the system to make landfall in either southwestern Louisiana or the Upper Texas coast Wednesday night or early Thursday. After landfall, Laura is forecast to continue moving northward before turning eastward on Friday as it becomes embedded in the mid-latitude westerlies. Although the global models are in relatively good agreement, there remains some spread in the ensemble members, especially in the ECMWF. Therefore, confidence in the track forecast is still not high. The NHC track forecast is slightly to the left of the previous one, trending toward the latest consensus aids. The storm is starting to pull away from the western portion of Cuba, and it should be over the warm Gulf of Mexico waters for about 2 days. Since Laura will have a notable amount of time over waters with high oceanic heat while moving through a low wind shear and high moisture air mass, significant strengthening seems quite likely until the storm makes landfall. The intensity models all show Laura making landfall as a hurricane, but there are differences on exactly how strong it will be. The NHC intensity forecast continues to stay near the consensus aids, which usually perform best, and Laura could be near major hurricane strengthen when it reaches the coast. Users are again reminded not to focus on the exact details of the track or intensity forecasts as the average NHC track error at 48 h is around 80 miles and the average intensity error is close to 15 mph. In addition, wind, storm surge, and rainfall hazards will extend far from the center. Key Messages: 1. Laura is forecast to reach the northwestern Gulf Coast as a hurricane late Wednesday and early Thursday. Do not focus on the details of the official forecast given the typical uncertainty in NHC's 2 to 3 day track and intensity predictions. In addition, storm surge, wind, and rainfall hazards will extend well away from Laura's center along the Gulf Coast. 2. There is a risk of life-threatening storm surge from San Luis Pass, Texas, to Ocean Springs, Mississippi, within the next 48 hours, and a storm surge watch is in effect for these areas outside of the southeast Louisiana Hurricane and Storm Damage Risk Reduction System. Residents in these areas should follow any advice given by local officials. 3. Hurricane conditions are possible by late Wednesday from Port Bolivar, Texas, to west of Morgan City, Louisiana, with tropical storm conditions possible by Wednesday afternoon, and a hurricane watch is in effect. Additional hurricane watches may be needed farther south along the Texas coast if the track forecast shifts toward the south and west tonight and Tuesday. 4. Tropical storm conditions and heavy rainfall are expected across central and western Cuba for several more hours. These rains could cause mudslides and life-threatening flash and urban flooding. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 22.7N 84.0W 55 KT 65 MPH 12H 25/1200Z 23.7N 86.3W 65 KT 75 MPH 24H 26/0000Z 25.2N 89.1W 75 KT 85 MPH 36H 26/1200Z 26.8N 91.6W 85 KT 100 MPH 48H 27/0000Z 28.8N 93.0W 95 KT 110 MPH 60H 27/1200Z 31.3N 93.6W 65 KT 75 MPH...INLAND 72H 28/0000Z 33.8N 93.0W 40 KT 45 MPH...INLAND 96H 29/0000Z 36.7N 89.1W 25 KT 30 MPH...INLAND 120H 30/0000Z 36.9N 77.1W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Cangialosi
Tags: number
discussion
storm
laura
Category:Transportation and Logistics