Even though Marco was a tropical wave off Cape Verde Africa first, names are not given until the tropical depression becomes a “tropical storm”. Laura won that race on August 21 by 12 hours, two days behind Marco.
When they crossed paths in the southern Gulf, they both had just attained hurricane strength . Marco was only at hurricane intensity for 12 hours then weakened back to tropical storm status and disapated! Laura continued to strengthen. Forecasters admit they underestimated the effects of wind shear on Marco after it made the left turn along the Louisiana coast. Marco then dissipated over water where two days later Laura would intensify to Category 4 major hurricane.
It must be noted this essay only deals with the causes of storms. Laura was an extreme weather event that killed people and caused wind and storm surge damage. Extreme, yes, but not unique. Even as a remnant low, Marco still produced thunderstorms and flooding rains. Nothing new on the Gulf Coast. But they have delicious sea food!
Second lesson: Laura showed that once a cyclone forms, the condition of the atmosphere above the low dominates over sea surface temperatures concerning intensity.
HURRICANE LAURA TEACHES TWO IMPORTANT LESSONS
The Galveston hurricane struck the Texas gulf coast 120 years before and a few miles west of Laura. They were identical Category 4 storms that bracketed the industrial age. The 1900 Galveston Hurricane stands as the deadliest natural disaster in American history. Still there are people who use Laura as evidence of coming disasters from climate change. (Horse feathers!)