Forget Seattle, San Francisco, Denver, and all the other sizzling west coast metros: there’s a new hot housing market. And just like one of its most famous mythical sons, it’s a bit of an underdog whose time has come.

Philadelphia home prices are on a tear, according to Econsult Solutions, an economics consulting firm based in the city. Econsult’s proprietary index shows double-digit annual price growth starting in mid-2016, with annual appreciation averaging over 20% throughout 2017.

Like any housing index, Econsult’s has some human adjustments that take into account seasonal sales patterns, quality and age of housing stock, and other factors. But unadjusted median sales prices show similar patterns: prices through the first quarter of the year are 15% higher than in the same period in 2016, for example, and surged to a 32% annual gain in April.

It’s also important to note that Econsult’s index covers the city of Philadelphia only. Other indexes that cover the metro area may include some of the more distressed inner-ring suburbs in Delaware County.

Also read:Existing home sales stall as tight supplies push properties to record low time on the market

The Philadelphia renaissance is an unusual turn of events for a city that’s often hidden in the shadow of New York or DC, but Jonathan Tannen, an Econsult director who’s studied housing markets throughout his career, thinks it makes sense.

“Philadelphia’s job market for a long time had lagged other comparable cities but finally in the last two quarters, we’ve seen faster job growth so that would suggest that these price gains are real,” Tannen told MarketWatch.

Pedestrians walk along Elferth's Alley, thought to be the nation’s oldest residential street, in Philadelphia. Bloomberg

Tannen is a Philadelphia native who spent two years with Teach for America in West Philadelphia after college. While he’s glad to see the city getting some economic traction, he can’t help but wonder whether the price gains are adequately backed by fundamentals, or if he should be worrying.

“Is this Philadelphia finally beginning to look like other Northeast cities with really tight, expensive housing markets, or is it a bubble?” he said.

Mark Zandi is another economist who’s a Philly-area native. He thinks the city is just hitting its stride. While there are some poor pockets of the city that are struggling, in general, Zandi said, “The economy is cooking. The downtown is booming – there are cranes everywhere. This is something you see only once in a generation or two,” he said.

In large part, Philadelphia’s success is down to luck, Zandi acknowledges. It’s long been a hub of “eds and meds” at a time when demographics strongly favor both colleges and universities and health care centers.

But there’s another driver of Philadelphia’s success. Comcast CMCSA, -0.70% continues to consolidate its hold on the telecommunications industry and is hiring like mad. In fact, it’s building a 59-story skyscraper to house its global headquarters.

Another bonus: Philadelphia sits dead center on the Amtrak corridor between its two more high-profile and more expensive neighbors, allowing people like Zandi who do business in both cities to live in the middle where it’s a lot cheaper.

“If we ever got it together and were able to improve the rail system, Philadelphia would literally boom,” Zandi said.