If you sensed a rapid, sudden increase in the temperature this morning, your senses didn't deceive you.
Between 8 and 8:12 a.m., the temperature shot from 36 to 56 degrees as winds pushed out a lingering temperature inversion and warmer air spilled down from the nearby mountains, the National Weather Service reported.
"It's pretty unique," said NWS meteorologist Mike Ottenweller. "We (usually) might see 10 degrees in an hour or something like that."
The sudden rise in temperature signaled the end of an 11-day inversion of stagnant air that kept the average high temperature at 34 degrees, five degrees below the normal average.
"The inversion we had over the top of us for the last week or so was rather strong," Ottenweller said.
Coastal winds helped to mix some of the warmer air originally trapped at higher elevations because of the inversion. In addition, air from the nearby Siskiyou Mountain range is compressed and becomes warmer as it spills into the Rogue Valley. Ottenweller compared the action to the way a bicycle pump is hot to the touch after several pumps compress and release air. It's called adiabatic warming.
"I think it was both of those things working together," Ottenweller said, adding the quick increase was the result of perfect timing. "The spike was really highlighted because we were already basically at our coldest point of the morning."
It didn't happen today, but such a rapid shift can mean quick ice and snowmelt, resulting in flooding and landslides.
"That can be a hazard of these types of winds and this type of warming," Ottenweller said.
He added he has seen temperatures shift from minus two degrees to 50 or 60 degrees in an hour during his time in Alaska.
The record for a similar phenomenon occurred Jan. 22, 1943, in South Dakota, NWS officials said. In that case, temperatures shot from 2 below zero to 45 degrees in about two minutes.
— Ryan Pfeil