Infrared satellite view of Hurricane Laura at 8:41 a.m. EDT Wednesday, August 26, 2020. Laura had just been upgraded to a category 3 hurricane with 115 mph winds. (Image credit: University of Wisconsin/CIMSS)

Hurricane Laura powered its way to major hurricane status overnight, putting on an impressive display of rapid intensification over the very warm waters of the Gulf of Mexico.

Laura is headed towards a landfall expected Wednesday night or early Thursday morning in northeastern Texas or western Louisiana as a major category 4 hurricane, and is expected to cause “catastrophic” wind and storm surge damage, according to the National Hurricane Center (NHC). Rain squalls from Laura’s outer spiral bands were already affecting the coasts of Texas and Louisiana on Wednesday morning, and they will increase in intensity throughout the day.

Laura rapidly intensified by an impressive 50 mph in the 24 hours ending at 11 a.m. EDT Wednesday, with the winds rising from 75 mph to 125 mph and the pressure falling from 990 mb to 956 mb. This far exceeds the definition of rapid intensification, which is a 24 mb drop in 24 hours. Buoy 42395, located just east of Laura’s eye on Wednesday morning, reported sustained winds of up to 76 mph, wind gusts as high as 107 mph, and a wave height of 37 feet (11 meters).

At 11 a.m. EDT Wednesday, Laura was already generating a storm surge of 1 – 3 feet along much of the Texas and Louisiana coasts; the largest surges, between 2.5 – 3 feet, were at Shell Beach, Louisiana, located to the southeast of New Orleans, and Freshwater Canal Locks, on the south-central coast of Louisiana. Laura’s storm surge can be tracked using the Trabus Technologies Storm Surge Live Tracker or the NOAA Tides and Currents page for Laura.

Figure 1. Visible GOES-16 satellite image of Hurricane Laura at 9:30 a.m. EDT Wednesday, August 26. (Image credit: NOAA/RAMMB)

Laura continues to rapidly intensify

At 11 a.m. EDT Wednesday, Laura was located over the waters of the central Gulf of Mexico, about 235 miles southeast of Galveston, Texas. These waters were a very warm 30 degrees Celsius (86°F). Laura was headed northwest at 15 mph with top sustained winds of 125 mph and a central pressure of 956 mb, putting it just 5 mph below category 4 strength.

Satellite images and data from the Hurricane Hunters showed that Laura has closed off a large eye about 30 miles in diameter. Intense thunderstorms with very cold cloud tops surrounded the eye and extended high into the atmosphere. The eye had not yet fully cleared out, which likely will occur by Wednesday afternoon as the hurricane continues to intensify.

High-level cirrus clouds were streaming out to the east and south of Laura, indicating good upper-level outflow on that side. Upper-level outflow was steadily improving to the north and west, showing that Laura was establishing a second outflow channel that connected up with the trough of low pressure over the central U.S. This improved outflow structure will help Laura intensify further on Wednesday afternoon. Laura was embedded in a moderately dry region of the atmosphere, with a mid-level relative humidity of 60%, but this dry air was not hindering the hurricane anymore, as the moderate wind shear of 10 – 15 knots affecting the storm was not high enough to drive the dry air into the well-developed inner core.

Figure 2. The 6Z Wednesday, August 26, 2020 forecast of the HWRF model, which successfully predicted Laura’s rapid intensification in previous runs. The model predicted a landfall around midnight Wednesday in western Louisiana as a category 4 hurricane with 140 mph winds and a central pressure of 937 mb. (Image credit: Tropical Tidbits)

Landfall near the Texas/Louisiana border imminent

There’s not much mystery on where Laura is going. The hurricane has made its expected turn to the northwest, and is headed toward a landfall near the Texas/Louisiana border around midnight Wednesday night. After landfall, Laura will turn to the north, following steering currents from a trough of low pressure over the central U.S. The rapidly weakening storm will then turn to the east on Friday, passing through the Tennessee Valley on its way to the mid-Atlantic coast, where it will move out to sea by Sunday.

Figure 3. Predicted wind threat from Hurricane Laura. (Image credit: National Weather Service Southern Region)

Intensification expected until just before landfall

Ocean temperatures are a very warm 30 degrees Celsius (86°F), and Laura will be passing over Gulf waters with very high heat content on Wednesday. Conditions for intensification will be very favorable until four to six hours before landfall, when strong upper-level winds from the trough of low-pressure steering Laura will bring a high 20 – 25 knots of wind shear and likely halt the intensification process. Interaction with land may also slow intensification at that time. Data from the Hurricane Hunters late Wednesday morning showed that Laura might be starting to develop concentric eyewalls, a process common in intense hurricanes, which leads to a temporary halt in intensification when the double eyewalls become fully developed. This process could slow down Laura’s intensification by Wednesday night. The top dynamical intensity models – the HWRF, HMON, and COAMPS -predicted in their 0Z and 6Z Wednesday runs that Laura would be a category 4 hurricane at landfall, with the 6Z COAMPS forecast calling for a category 5.

Laura a catastrophic storm surge threat

Figure 4. Predicted storm surge threat from Hurricane Laura. (Image credit: National Weather Service Southern Region)

Laura will drive a massive catastrophic storm surge to the coast, with the 11 a.m. EDT Wednesday NHC advisory calling for a peak surge of 15 – 20 feet along the western Louisiana coast. The magnitude of this storm surge will depend not only on how strong the winds are, the speed the storm is traveling, and the angle at which it approaches the coast, but also on the size of the storm. A large storm with winds blowing over a wide area of ocean will typically generate a higher storm surge that covers a larger area than a smaller hurricane.

The 11 a.m. EDT Wednesday NHC forecast called for Laura’s tropical storm-force winds to span a diameter of 220 nautical miles (nm) at landfall. For comparison, Hurricane Rita in 2005 – a low-end category 3 hurricane with 115 mph winds which drove a 10 – 15-foot storm surge to the southwest Louisiana coast – had tropical storm-force winds that spanned a diameter of 300 nm. Hurricane Ike in 2008 – a high-end category 2 hurricane with 110 mph winds that drove a storm surge of 15 – 20 feet to Texas’ Bolivar Peninsula – had a tropical storm-force wind field 390 nm across. (Thanks to weather.com’s Jon Erdman for this information) Given that Laura likely will be a much stronger storm than Rita at landfall, but smaller in areal size, a peak storm surge of 15 – 20 feet – larger than the 10 – 15-foot storm surge Rita brought to southwest Louisiana (see below) – is a reasonable forecast.

Inundation levels also will depend on whether Laura strikes at high or low tide. Tidal ranges are low in this part of the Gulf, however. The tidal range at Lake Charles, Louisiana is 1.5 feet, and high tide is at 6:09 a.m. CDT Thursday.

Figure 5. Holly Beach, Louisiana on November 16, 2005, after strong waves and storm surge currents from Hurricane Rita completely destroyed all 500 structures in the town and stripped away most of the vegetation, leaving deep scour channels parallel to the shoreline. Holly Beach was completely destroyed also in 1957 by the 12-foot storm surge of category 3 Hurricane Audrey. After both hurricanes, the town was partially rebuilt. (Image credit: Marvin Nauman/FEMA)
Figure 6. Simulated storm surge from Hurricane Rita of 2005, using water-level and barometric pressure data from sensors. (Image credit: USGS)

An impact greater than Hurricane Rita’s in 2005 likely

After peaking as a category 5 storm with 180 mph winds and a central pressure of 895 mb – the fourth lowest pressure ever measured for an Atlantic hurricane – Hurricane Rita weakened to a category 3 storm with 115 mph winds before making landfall in western Cameron Parish, Louisiana, near the Texas border, on September 24, 2005. Rita caused an estimated $25.2 billion in damage, making it the eleventh-costliest hurricane in U.S. history. Seven direct deaths were blamed on the storm, and the chaotic evacuation of Houston was blamed for 107 deaths.

When a hurricane threatens, don’t underestimate storm surge risk

The small town of Cameron (population 2,000 and elevation three feet) was the largest town along the stretch of southwest Louisiana coast that received Rita’s peak storm surge, estimated to be 10 – 15 feet. The storm surge destroyed 90% of the homes in Cameron, and destroyed all of the structures in Holly Beach (population 300), with the only human-made features remaining after the storm being power poles, concrete slabs, and roads. Rita’s surge penetrated more than 30 miles inland, reaching Interstate 10. The surge, combined with freshwater flooding, inundated downtown Lake Charles, located 30 miles from the ocean, up to six feet deep. Rita also produced a storm surge of 4 – 7 feet in coastal areas of southeastern Louisiana, flooding some spots that had already been impacted by the surge from Hurricane Katrina about one month earlier.

Posted August 26, 2020, at 12:35 p.m. EDT.

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Jeff Masters, Ph.D.

Jeff worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a safer passion -...

569 replies on “Hurricane Laura intensifies; ‘catastrophic’ wind and storm surge expected”

  1. Possible AOI in Western Caribbean looks to be thriving. No convergence yet. Latest vort maps just updated. This Western Caribbean convection now has a low level vorticity signature in the area. Looking at Lake Charles today, reminds me of driving through the EF-3 160mph Seneca, S.C tornado damage the day after. Was a bad tornado very near me this Spring. Very similar damage. The 850mb signature is not super close to the actual blowup of convection over the W. Caribbean today. https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/gm/13/1000×1000.jpg

  2. Lake Charles, Louisiana is destroyed. Much of the Gulf Coast, especially Arkansas is way above seasonal average for rainfall. Arkansas soil saturation rates were already through the roof before Hurricane Laura. Damage reports coming in show Hurricane Laura was an absolute buzzsaw. Lake Charles looks like an EF-3 hit the entire city, and we can expect similar damage far beyond Lake Charles, as we are seeing. Had Hurricane Laura made landfall in a heavily populated area we’d of seen a much bigger problem. All and all fortunate landfall was where it was. Though I am sorry anyone is dealing with the aftermath today.

  3. The MDR is very active today. 3 strong TWaves and one over africa is sure a precursor of what to expect the remainder of the season. Expect Nana to form before 31st August 2020

  4. H. Ike had the highest surge on record for this part of the Gulf with 110mph winds at landfall. But it was huge and had been a huge storm for much of its path across the Gulf. Recent research has confirmed that size of the storm is more important than wind speed when it comes to storm surge. I don’t think we know the surge height of H. Laura yet, but I’d be surprised if it were as large as Ike’s. H. Katrina was also a large storm and when the winds came down as it approached landfall I think lots of folks breathed a sigh of relief. But despite the lower winds its surge was monstrous. Dr. Master’s wrote a comprehensive article on H. Ike’s surge. It’d be great to have a link to that.

    1. Not sure if we can link that here or not. It’s an easy look up under Jeff Master’s writes and put in key words. Tried to link something from the old blog and was unable the other day.

  5. Surge really was the big dodge we all know with Hurricane Laura. Many reasons why. Not mature enough major to build a big surge, the parallel approach, and I’d add the CDO was always SW loaded. I thought the narrow NE CDO/Eyewall was indicitive of a strong forcing that would send in massive surge. Looks like it was very much the opposite. Loss of life looks to be extremely low for the U.S. Haiti took a hard hit of loss of life from Laura. Between Haiti and the Dominican Republic, over 30 deaths attributed to Hurricane Laura so far. We see this all the time the day after, people think somehow the damage isn’t that bad, Lake Charles is a disaster zone today. We were very fortunate that one of the least populated areas in Louisiana was the landfall area.

    1. “Surge really was the big dodge …”

      Can you explain, please? What figures do you have?

      1. What figures do I have? How bout not a morgue full of people? Of coarse obviously surge was the really big dodge. If you had seen the expected storm suge into Lake Charles you could have answered your own question.

      2. Thanks for your replies. I wasn’t attacking you, Wyatt. I just wanted to know what figures you had.

      3. Sorry for my terseness. We may soon find much greater storm surge did occur. Thankfully the deadly aspect was what we dodged. Once again appologies, guess I feel like that Johnny Depp pirate meme where Jack Sparrow is being chased in my almost decade on the old Blog. All I said….. Hope you have a great day JCL42.

  6. Looks like EF-3 damage throughout Lake Charles, Louisiana. Massive structural damage. Clearly major hurricane damage throughout the city.

  7. Brick structures crumpled, Golden Corral destroyed, Apartments patrially collapsed, untold buildings and homes have taken major damage across Lake Charles. Total destruction of many structures in the city. Everyone here and on the backup was screaming for Stephanie Abrams to get inside early in the morning as she was in the heart of Laura outside her location. She got the message and was telling the viewers, “I’m fine”, as she went inside the overhang from where she was standing outside. Not a minute later mass class from busting windows crashed down right where she was standing. I’m not sure if it was another legit assist from the blog for saving life, but it sure was some interesting timing. Hopefully they will get her a helmet next time.

  8. Seeing wide extensive wind damage around Lake Charles from the livechasers and remember that like 30 miles from the coast.

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