Right after seeing Alabama Shakes for the first time, at last year's South by Southwest music festival in Texas, I tweeted out a somewhat bold prediction:

The band would win the 2013 Grammy for best new artist.

I was close. The folksy blues-rock group was indeed nominated in that prestigious general-field category, but ended up losing to the juggernaut known as fun.

There's no doubt, however, that Alabama Shakes has otherwise lived up to much of the promise shown in Austin -- where it was the definitive "buzz band" of the 2012 SXSW. Since our initial dance, the group has released the debut record "Boys & Girls" and watched it climb into the upper echelon of the charts in the U.S. and elsewhere. It's also made frequent appearances on TV, such as during a recent episode of "Saturday Night Live," and ended up scoring three Grammy nominations.

Alabama Shakes lead singer Brittany Howard performs in concert at the Fox Theater in Oakland, Calif., on Tuesday, March 5, 2013. (Ray Chavez/staff)
Alabama Shakes lead singer Brittany Howard performs in concert at the Fox Theater in Oakland, Calif., on Tuesday, March 5, 2013. (Ray Chavez/staff) ( RAY CHAVEZ )

Most significant, Alabama Shakes has transformed into one of the hottest acts on the concert circuit. The group's set at last summer's multistage Outside Lands festival in Golden Gate Park drew one of the biggest crowds of the weekend and it quickly sold-out its show on Tuesday at the Fox Theater.

The Oakland concert underscored exactly why Alabama Shakes has quickly grown so popular. It can be precisely explained in two words:

Brittany Howard.

She's a vocalist of nearly unfathomable potential, blessed with a divine growl of a voice that reminds one of Janis Joplin. She sings with heart — tons of it — and mixes an old-fashioned blues vibe with a Top 40 sensibility as well as anyone has in decades.

Yet, one thing was painfully obvious during the Fox gig -- move beyond Howard's striking vocals and there really isn't much that's notable about Alabama Shakes. The other band members come across like anonymous sidemen, who could be replaced by basically any other competent musicians without drastically impacting the sound. Plus, its current songbook, minus a few notable exceptions, is just so-so. That could — and should — change once the band has a few more albums under its belt.

If nothing changes, however, Howard's vocals still might be enough to carry this band for the foreseeable future. She's that kind of a talent, yet one wonders for how long she'll be willing to do all the heavy lifting in Alabama Shakes before a solo career beckons brightly.

Much like on its debut record, Alabama Shakes walked a tightrope in concert between many musical styles, from blues to pop to jam-rock. The crowd ate it up eagerly, cheering with gusto for the single "Hold On" (nominated for the best rock performance Grammy) and other selections from "Boys & Girls."

Despite the many different elements, Alabama Shakes' music comes across as very mainstream -- like something designed to be played for the folks who once listened to Norah Jones at the local Starbucks. Definitely file this band alongside Mumford & Sons, the Lumineers, Florence and the Machine, Imagine Dragons and other highly commercial bands that are masquerading as indie-music sensations. It's a return to the earthy pop sounds that ruled the mid-'90s, when the Dave Matthews Band, Hootie and the Blowfish and the Gin Blossoms were dominating airwaves.

Hey, but maybe the world needs a few new Dave Matthews. (Ironically, Alabama Shakes is signed to Matthews' ATO Records label.)

Overall, the concert showed that Alabama Shakes is worthy of much of the hype it's been generating since last year's SXSW. Howard is indeed a major talent. Now, it's time for the other band members and the songbook to catch up.

Follow Jim Harrington at http://twitter.com/jimthecritic, www.facebook.com/jim.bayareanews and http://blogs.mercurynews.com/aei/category/concerts.