Laura Likely To Approach Category-4 Hurricane Intensity in the Northwest Gulf Wednesday Night

Laura and Marco Face Different Hazards Trying to Intensify
08/22/2020, 8:11 am EDT
NOAA/NHC Now Forecasting 15-20 Foot Storm Surge Southwest Louisiana Coast
08/26/2020, 11:58 am EDT
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Fig. 1: NOAA/NHC forecast track for Tropical Storm Laura.

Fig. 2-3: Hurricane forecast models (HWRF and HMON) and their maximum wind speed projections for early Thursday in the northwest Gulf of Mexico.

Discussion: At 5AM EDT Tropical Storm Laura was located at 22.9N/85.7W or about 85 miles northwest of Cuba. Laura is now into the southeast Gulf of Mexico and should reorganize quickly and become a hurricane later today. Currently, Laura is moving west-northwest at 17 mph with top wind 65 mph and surface pressure 995 MB. Laura is forecast to move west-northwest along the southern periphery of an upper ridge pattern located over the Southeast U.S. The northwest to north-northwest turn into the northwest Gulf for a landfall early Thursday morning near the TX/LA state line is caused by a weak upper trough over Texas associated with lingering upper shear which wrecked Marco yesterday. Forecast confidence in that Texas trough turning Laura toward the north-northwest is LOW. Tropical cyclone models indicate the trough may weaken allowing Laura to track farther west before making landfall. The warm Gulf water and low shear environment should encourage rapid development of Laura. The HWRF model indicates 134 mph wind prior to landfall which is certainly possible. At landfall Laura should be a strong category 3 hurricane or minimal category 4 hurricane. Widespread damage due to massive storm surge, hurricane force wind and heavy rain should be planned for now for Houston to Port Arthur to New Orleans. Once Laura is inland a steady track northward into the Missouri Valley is expected followed by a hard-right turn toward the Mid-Atlantic region this weekend. The interaction between Laura and the jet stream to the north will make for unusually strong wind despite well inland placement late week/weekend.

Fig. 4-5: NOAA/NHC hurricane and tropical storm force wind speed profiles associated with Laura.

Fig. 6-7: Tropical cyclone model tracks are farther west at landfall vs. the NOAA/NHC track. Intensity forecasts indicate slight risk of a category-3 major hurricane. Expect the intensity forecasts to increase toward/into category 4 intensity by tomorrow.