Questions about the incredible images of ping-pong ball sized stones forming a four-foot deep wall on the Texas panhandle were answered Friday when the National Weather Service declared them legitimate -- with a warning that you ain't seen nothing yet.
Baseball- or even softball-sized hail could hit the South this weekend, NWS officials warned Friday.
“I do think we’ll see larger hail over the next couple days,” Justyn Jackson, a meteorologist with the Amarillo, Tex., Weather Forecast Office, told FoxNews.com. “It’s possible that we could maybe see baseball-sized hail, maybe even softball-sized. That’s not out of the realm of possibility.”
“We think it’s going to be east of our area -- Oklahoma, Kansas, those areas,” Jackson said.
Forecasters at the Storm Prediction Center in Norman, Okla., an arm of the National Weather Service, issued a stronger warning Friday. There's a high risk of severe weather from Oklahoma City north to Salina, Kan., they said. The severe storms are expected to strike Saturday afternoon and evening.
“Folks in the broader Great Plains should monitor this situation closely,” warned Jack Hayes, co-director of NOAA’s National Weather Service.
Images posted on the NWS Facebook page late Thursday showed some of the six scientists and meteorologists sent to the sparsely populated region of Potter County, where hailstones the size of golf balls or ping-pong balls fell following a severe and slow moving thunderstorm that drifted over the Texas panhandle.
The National Weather Service estimated that in 2 hours in the late afternoon, 5 to 6 inches of rain fell in a very small area in Northern Potter County, 26 miles north of Amarillo.
“We had a slow moving thunderstorm develop about 20 miles northwest of Amarillo that parked itself over the northern part of Potter County -- it produced quite a bit of hail,” Jackson said.
One picture showed a Potter County fireman standing near what appears to be a giant gray boulder, about shoulder height -- actually a block of ice compacted by rain and floodwater across the area.
“Hail ... up to the size of golfballs fell with the heavy rain,” the Weather Service said in an advisory. More severe even than golfballs falling from the sky was the runoff from the heavy rains, which pushed the hail into three to four foot drifts across U.S. Highway 287 -- closing the route for over 12 hours due to flooding.
Jackson said hail drifts were up to the hood of a Chevy Tahoe.
Three factors combine to cause thunderstorms: lift, often in the form of a cold front; warm moist air at the surface; and instability.
"You combine those three ingredients and you get the development of thunderstorms,” Jackson explained.
Water molecules are pushed up into the cold air by the updraft of rising warm air, where they freeze, get heavy enough to leave the updraft and fall. Without strong winds to move them, Jackson said they can get stuck in a cycle, being raised again by the drafts to pick up a second ring of ice, gaining size.
"Hail size is dependent on how strong the updraft is in thunderstorm,” Jackson said. “[Updrafts] were weak that day, so the storms really didn’t move fast at all.”
Severe thunderstorms are predicted to develop over the far eastern Panhandles Saturday evening, and even larger hail and locally heavy rain, the National Oceanic and Atmospheric Agency warned Friday.
Meanwhile, Amarillo is still reeling from the unusual situation -- although it has happened before, Jackson told FoxNews.com.
“We had a situation in March of ‘93 near a town called Dalhart, 1.5 hour west of Amarillo,” Jackson said. “We had hail that accumulated up to six feet there. It was on the ground for about a month."