Thunderstorms possible this weekend

·3 min read

Jun. 30—There's a chance Mother Nature could contribute a few fireworks of her own this Fourth of July weekend.

A weak low-pressure system will approach the Rogue Valley starting Friday and move into the area Saturday and Sunday, bringing some clouds and potentially a few scattered showers this weekend, according to meteorologist Mike Petrucelli with the National Weather Service in Medford.

Along with precipitation will come a roughly 20% chance of thunderstorms starting Saturday evening. Petrucelli said any thunder and lightning is expected to be sporadic.

The storm system coming through will create the warm surface temperatures and cool aloft temperatures that can result in an unstable atmosphere, but Petrucelli said he expects that any thunderstorms will die down by about 7 or 8 p.m.

Showers throughout the evening are possible starting Saturday evening, but the probability of thunder and lighting will decrease as surface temperatures drop.

"The further along in the evening hours, the less you're going to see a thunderstorm," Petrucelli said.

As a precaution, Petrucelli encouraged campers, boaters and lake swimmers to find shelter if they hear thunder.

If thunderstorms do appear, Petrucelli said, "It's not going to be an all-day event."

The thunderstorms are predicted to occur just as fire danger bumps up a level from "low" to "moderate," effective Friday across lands protected by the Oregon Department of Forestry Southwest Oregon District and within the Rogue River-Siskiyou National Forest.

Effective as of 12:01 a.m. Friday, all open fires are prohibited except at authorized locations at designated campgrounds. Chainsaws, cutters, grinders and welders are not allowed between 1 and 8 p.m., and mowing of dead or dry grass is not allowed between 1 and 8 p.m. Motorized vehicles, including motorcycles and ATVs, are allowed only on "improved roads free of flammable vegetation," and motorists must travel with either a 2.5-pound fire extinguisher or larger, or a shovel and a gallon of water.

On the Rogue River-Siskiyou National Forest, the Industrial Fire Precaution Level will remain at Level 1, which requires a fire watch of at least one hour after a fire is extinguished.

The forecast this weekend calls for mostly sunny skies and mostly clear nights Friday and Saturday with highs in the 80s and lows in the 50s. There's a 20% chance of showers Saturday night, a 30% chance of showers Sunday and a slight chance of showers Monday.

Petrucelli said that despite the chance of rain in the forecast, it's unlikely to rain out any barbecues, parades or fireworks shows.

He said he anticipates the forecast will mean a little added cloud cover in the middle of the day and — at worst — a brief scattered shower.

"Odds are little or nothing is going to happen on the Fourth," Petrucelli said. "I think most areas and most hours are going to be dry."

By Monday, the chances of thunderstorms are expected to shift northward out of the Rogue Valley. Starting Tuesday, the latest NWS forecast for the Medford area calls for a return to sunny, clear skies with highs in the 80s and lows in the 50s.

Reach web editor Nick Morgan at 541-776-4471 or nmorgan@rosebudmedia.com. Follow him on Twitter @MTwebeditor.