UPDATE: Round 2 of storms forecast amid trees down, power loss
Lehigh, Northampton, Warren and Hunterdon county communities could see a powerful thunderstorm Monday, the National Weather Service announced.
The weather service shortly before 4 p.m. upgraded a severe thunderstorm watch to a warning for portions of the Lehigh Valley region.
The warning was originally issues until 4:45 p.m. for an area that encompasses northwestern Lehigh County, all of Northampton and Warren counties and northeastern Hunterdon County. The weather service later extended the warning until 5:30 p.m.
A severe thunderstorm watch remained in effect until 8 p.m. Monday for an area encompassing Lehigh, Northampton, Warren and Hunterdon counties.
The storm headed east at 40 mph could generate 60-mph wind gusts and nickel-size hail, according to the warning.
"Expect damage to roofs, siding and trees," the warning reads. "In addition to hail and damaging winds, frequent cloud-to-ground lightning is occurring with this storm.
"Move indoors immediately. Remember, if you can hear thunder, you are close enough to be struck by lightning."
Kurt Bresswein may be reached at kbresswein@lehighvalleylive.com. Follow him on Twitter @KurtBresswein. Find lehighvalleylive.com on Facebook.