Expected wind shear not slowing Laura’s growth

Despite early predictions of atmospheric disturbances that might have weakened it as it approached the coast, an extremely dangerous Hurricane Laura has the signature of a classic hurricane on satellite images, with a well-defined eye surrounded by very deep convection.

There is little evidence of shear, and the upper-level outflow pattern is extremely well defined, while the cyclone is over sea surface temperatures near 86 degrees F.

Observations from both NOAA and Air Force Hurricane Hunter aircraft show that Laura continued to strengthen during the evening. The storm’s wind intensity is estimated at just shy of 150 mph.

Since there is now little time remaining for the system over water, no significant change in intensity is anticipated until the center crosses the coastline. Laura will weaken rapidly after it begins  to move over land, but destructive winds should spread more than 100 miles inland along its path.

Global models indicate some re-intensification as the remnants of Laura move off the U.S. east coast.

Laura has begun to turn northward as it moves around the western side of a subtropical high pressure area at about 15 mph.

The cyclone should move through a weakness in the high-pressure ridge and turn to the northeast over the next day or two. Then the system should accelerate toward the east-northeast while embedded in the westerlies.

Unsurvivable storm surge with large and destructive waves will cause catastrophic damage from Sea Rim State Park, Texas, to Intracoastal City, including Calcasieu and Sabine Lakes.

This surge could penetrate up to 40 miles inland from the immediate coastline, and flood waters will not fully recede for several days after the storm.

Hurricane-force winds are expected tonight in portions of the hurricane warning area, with catastrophic wind damage expected where Laura’s eyewall moves onshore. Hurricane-force winds and widespread damaging wind gusts will spread well inland into portions of extreme eastern Texas and western Louisiana early Thursday.

Widespread flash flooding along small streams, urban areas, and roadways is expected to begin overnight tonight into Thursday from far eastern Texas into Louisiana and Arkansas. This will also lead to minor to moderate freshwater river flooding. The heavy rainfall threat and flash and urban flooding potential will spread northeastward into the middle-Mississippi, lower Ohio, and Tennessee Valleys Friday night and Saturday.