It’s been almost four months since the mighty Kotzschmar Memorial Organ has been in the hands of its official organist, but that drought ends April 18 when James Kennerley sits at the console and plays his first concert since being named Portland municipal organist.

Quite appropriately, his debut program comprises overtures.

There’s a lot more going on. On Saturday, the New York-based Jessica Lang Dance troupe will present an evening of cutting-edge choreography, including its eponymous founder’s masterpiece, “Thousand Yard Stare.”

Portland Chamber Music Festival is holding one of its “off-season” concerts on Sunday, focusing on cutting-edge works by modern composers.

There are two more good choices for April 18. Singer-songwriter Mary Gauthier will appear in Portland. Ditto the Ariel String Quartet with guest pianist Navah Perlman.

Friends of the Kotzschmar Organ

When Ray Cornils took his final bow as Portland’s 10th municipal organist last December, attention turned to his successor, British-born James Kennerley, who had recently been named the 11th.

Kennerley will perform his Portland debut concert on April 18, and he’s chosen a thematically appropriate program – entirely overtures. Great beginnings.

The opening number will be familiar to all, including people who have no connection to classical music or the organ canon: The “William Tell Overture” was used for years as the intro to the “Lone Ranger” television series. Originally composed for full orchestra by Gioachino Rossini, Kennerley wrote the organ transcription himself.

Two other pieces carry a Kennerley transcription credit, including Leonard Bernstein’s overture to the 1956 Broadway musical “Candide.” I much appreciate that Portland’s new maestro of the Kotzschmar likes to transcribe; it strongly suggests that we’ll be hearing a more varied repertoire in the future.

Kennerley’s Portland debut lists seven pieces by seven different composers and represents a time span from the 1800s and 1900s plus one contemporary work. I’ve reserved my tickets and I’m expecting a great show.

Friends of the Kotzchmar Organ present James Kennerley’s debut concert at 7:30 p.m. April 18 at Merrill Auditorium at Portland City Hall. Call PortTix at 842-0800.

Jessica Lang Dance

A modern dance troupe that’s making waves and getting attention from critics and audiences alike will be visiting Portland. Jessica Lang Dance will perform a varied repertoire under the aegis of Portland Ovations this Saturday.

The company founder is a Pennsylvania native who graduated from the Juilliard School’s dance program and trained with Twyla Tharp’s famously innovative company. Since 2011 Lang has been innovating independently with her own New York-based troupe, which has appeared at all the world’s major festivals and concert halls.

Her masterpiece is a stark interpretation of warfare that will be performed in Portland. “Thousand Yard Stare” is a nine-person, 20-minute piece set to music by Ludwig van Beethoven. “Thousand Yard Stare” garnered rave reviews in Boston, New York and elsewhere. Boston Globe critic Janine Parker commented that “the rituals of war are rendered with abstract simplicity, while the losses rush at one with a throat-catching straightforwardness.”

Portland Ovations presents Jessica Lang Dance at 8 p.m. April 14 at Merrill Auditorium at Portland City Hall. Call PortTix at 842-0800.

Portland Chamber Music Festival

Portland Chamber Music Festival, now in its 25th season, is a nationally known concert series that’s held every August. Less known are PCMF’s “off-season” concerts, which tend to emphasize special themes and purposes.

This Sunday, PCMF has scheduled one of its ongoing SPACE Gallery concerts in downtown Portland.

Begun in 2012, this series emphasizes cutting-edge compositions, often by living composers. This Sunday’s program title is “Four By Four,” and it comprises four works and four musicians. Two of the players are longtime PCMF artists. Violinist Jennifer Elowitch is the festival’s founder and artistic director. Violinist Sunghae Anna Lim played at the very first festival in 1994 and has returned often. Violist Noriko Futagami and cellist Rhonda Rider are prominent performers and pedagogues in the Boston area.

Elowitch’s program includes noted works by mid 20th-century composers, Erwin Schulhoff and Dmitri Shostakovich, and pieces by living American composers Terry Riley and John Harbison.

Catch this concert at 7:30 p.m. April 15 at SPACE Gallery, 538 Congress St. in Portland. Call 800-320-0257.

Mary Gauthier

Mary Gauthier is a singer-songwriter who is involved in a very interesting project. Teaming up with wounded American veterans, Gauthier helps these vets create music based on their own stories and their own experiences. They were co-written through Songwriting With Soldiers, an organization that facilitates retreats pairing professional songwriters and wounded veterans.

Gauthier believes that her own survival skills – she spent years wrestling with alcohol and drugs – help her empathize with the veterans and help them develop their own abilities to face new and often radically different circumstances. An ability to empathize is a key factor in the healing process, she believes. So is the ability to discover new and creative outlets for coping and moving on.

Gauthier has collected a number of these co-written songs on her newest CD, “Rifles & Rosary Beads,” which was released a couple of months ago. She’s now on tour in support of the album, and will be appearing at 8 p.m. April 18 at One Longfellow Square, corner of Congress and State in Portland. Call 761-1757.

Ariel String Quartet

When the Portland Concert Association was organized in the 1920s, its initial mission was to bring classical music to the city. Since that time its name has morphed a few times – it’s now Portland Ovations – and its mission has expanded considerably.

But classical music remains a core mission, according to artistic and executive director Amy Petrin, and on April 18 that long-running commitment will be on display as the Ariel String Quartet visits Portland.

This is one of the newer ensembles on the classical circuit. The four musicians graduated from the New England Conservatory’s professional string quartet program in 2010, and they appear to be on the verge of a brilliant career. Characterized by youthful energy, dazzling technique, and soulful interpretation, the Ariel String Quartet has quickly earned a glowing international reputation.

In their Ovations debut, the foursome will be joined by pianist Navah Perlman, known for a lyrical eloquence that has established her reputation as a highly poetic and admired artist. Their program will include works by Wolfgang Amadeus Mozart, Bela Bartok, Robert Schumann and Johannes Brahms.

This concert will be presented April 18 at 7:30 p.m. at the Abromson Community Education Center, 88 Bedford St. on the University of Southern Maine’s Portland campus. Call PortTix at 842-0800.

James Kennerley, the city of Portland’s 11th official municipal organist, will perform his debut concert on the Kotzschmar Memorial Organ on April 18.