The National Hurricane Center announced Wednesday night that Arthur has officially been downgraded from a tropical cyclone to a post-tropical low, after the storm’s structure broke down along the Upper Texas coastline.
According to forecasters, surface observations showed that Arthur’s center briefly re-formed near Galveston between approximately 9 and 10 p.m. Eastern time Wednesday following an offshore burst of thunderstorm activity. However, organized storm activity near the center soon disappeared, and the circulation stretched out along the Upper Texas coast — prompting the downgrade. The system is now carrying maximum sustained winds of 30 knots.
The storm’s path remains somewhat uncertain due to the center reformation, but forecasters estimate it is beginning to pick up speed, moving toward the northeast at around 8 knots. The surface center is expected to fall apart later Wednesday night over southeastern Texas or southwestern Louisiana. After that, the remnants of Arthur are forecast to track east-northeastward across the southeastern United States before emerging into the Atlantic Ocean on Friday, continuing out to sea from there.
Although the surface center is expected to dissipate, global weather models indicate it could potentially re-form near the Atlantic coast on Friday, with some strengthening possible as it moves offshore. Forecasters say it remains unclear whether any redevelopment would result from tropical or non-tropical weather processes. As a precaution, marine gale warnings have been issued for portions of the western Atlantic.
Despite losing its tropical cyclone designation, Arthur continues to pose significant dangers. Forecasters warn that heavy rainfall and life-threatening flash flooding will remain a major concern across the southeastern United States for the next several days. An elevated tornado risk is also in place for parts of the Southeast through Thursday.
Key hazards outlined by forecasters include: potentially life-threatening flash flooding and urban flooding likely through Friday across southern Louisiana, southern Mississippi, southern Alabama, southwestern Georgia, and the Florida Panhandle; the possibility of scattered minor river flooding, with isolated moderate to major river flooding; wind gusts reaching tropical-storm force along portions of the Louisiana coast Wednesday night; and coastal flooding along the Texas and Louisiana coasts expected to gradually ease later tonight and into Thursday.
Wednesday night’s update marks the final advisory the National Hurricane Center will issue on Arthur. Rainfall forecasts and flash flood risk outlooks for the storm’s remnants will continue to be available through the Weather Prediction Center.
