Unbelievably, Tropical Storm Elsa continues to be within the information. It made landfall in Florida on Wednesday and is now dragging a “rainfall footprint” all the way in which up the I-95 hall to the Northeast. As I monitor the storm, it’s clear to me that Elsa is now a member of a considerably uncommon membership known as TCMI. What’s that anyhow?
By now, you might have heard dialogue about one thing known as the Brown Ocean Impact. Let’s get it out of the way in which proper now. Elsa in all probability is not an instance of that idea. The Brown Ocean Impact (a very good abstract could be discovered right here) is constructed upon the concept that antecedent soil moisture or wetlands might trigger a storm to take care of depth of strengthen overland. The poster youngster for that is Tropical Storm Erin from 2007. It actually developed a watch over Oklahoma and maintained a heat core construction in accordance with research within the peer-review literature. There have been a number of follow-up research within the literature and even a devoted Wikipedia web page.
Tropical Cyclone Upkeep and/or Intensification or TCMI was launched in a 2014 research revealed within the Worldwide Journal of Climatology by one among my former college students, Dr. Theresa Andersen. It outlined TCMIs as tropical cyclones that maintained depth or strengthened over land via extratropical transition (see hyperlink for clarification), the Brown Ocean Impact, or a hybrid course of. NASA’s web site summarized the TCMI research and famous that, “Of the 227 inland tropical cyclones recognized (within the research from 1979 to 2008), 45 maintained or elevated energy, as decided by their wind pace and central stress.” Like Hurricane Sandy in 2021, 17 of them had been via the method of shifting from heat core and ocean water “gas” to chilly core and power from air plenty variations (temperature gradients). 18 of the storms had been heat core “Brown Ocean” kind programs, and the remainder of the storms had been hybrids.
On Thursday Andy Hazleton, a hurricane professional on the College of Miami, tweeted, “The (land friction) by no means bothered #Elsa anyway!” He was referring to information displaying that Elsa truly elevated in depth over land whereas making its manner from the Southeast into the Mid-Atlantic. The Nationwide Hurricane Middle remarked in its afternoon dialogue, “Elsa’s slight strengthening could also be the results of baroclinic forcing related to an approaching short-wave trough.” This actually qualifies as a TCMI. Whereas not a lot extra strengthening is predicted, the method of extratropical transition will proceed.
Dr. Joe Santanello and colleagues at NASA Goddard, with funding from NASA’s MAP program, has began to optimize the company’s land-atmosphere modeling capabilities to check the sort of hydrometeorological phenomena. A 2020 research within the Journal of Hydrometeorology explored a TCMI occasion in Australia and questioned the function of the Brown Ocean Impact in comparison with atmospheric moisture transport.
Oh by the way in which, the climate system producing rainfall off the coast of Texas this week caught my eye too. It has been a prolific rain-producer and has exhibited tropical traits although it by no means was named. Does that sound acquainted? Components of Louisiana had been inundated in 2016 from an unnamed tropical “factor” that U.S. Nair and colleagues (2019) attributed to TCMI hybrid course of involving atmospheric processes and underlying wetlands within the space.