Natural gas prices are making some unnatural moves.
After a nearly 40% rally in the last month — an unusually outsized move for any commodity — the charts are now flashing warning signs, Miller Tabak's Matt Maley told CNBC's "Trading Nation" on Thursday.
Natural gas prices fell by about 3.5% on Thursday after climbing nearly 4% in the previous session.
"Even though I'm bullish longer term, I just think the thing has become overbought," the firm's chief market strategist said.
When natural gas prices spiked Wednesday, their relative strength index reached 80, a level that has "signaled near-term tops" throughout much of this year, Maley said.
"On its weekly chart, it also got above 80, and that's the second highest, the second-most overbought it has been in a decade," Maley said.
"This doesn't mean that the bull market is over for this commodity. I just think that when you get a weekly chart that's that overbought, the pullback's going to last for more than a couple of days, and [Thursday's] pullback I think won't be the end of it," he said. "We're going to have to see a pullback that lasts for more than just a few days."
The commodity found another long-term bull but near-term worrier in Nancy Tengler, the chief investment officer of Laffer Tengler Investments.
Her firm recently launched a green energy-based product for its clients that owns some natural gas stocks but hedges them with oil, she said in the same interview.
"I think we are due for a pullback, but long term, this is a relatively clean solution to energy, and I think we're going to continue to see strength in natural gas over the coming years from a fundamental standpoint," she said.