The rain clouds that blew across parts of southwestern Pennsylvania last night contributed to nearly optimal conditions for today's opening day of trout season.

Just enough rain fell last night to swell and slightly stain many creeks throughout the region. Even yesterday's weather report helped -- threats of downpours that never occurred convinced many anglers to head for the lakes, leaving lots of elbow room on moving water.

In Westmoreland County, Waterways Conservation Officer Ron Evancho was all smiles.

"The fishermen are happy," he said, pouring himself a cup of coffee at a convenience store. "When they're catching fish we have fewer problems, and this morning we're seeing a lot of limits taken."

Jacobs Run and Linn Run, mountain streams that were stocked Friday, were slightly high and stained, said Evancho, and many anglers limited out early.

Loyalhanna Creek was nearly perfect: 50 degrees, a little bit of color, and lower-than-average angling pressure in most places from Rt. 711 to Kingston Dam. Fly and spinner anglers who chose the Delayed Harvest Artificial Lures Only area found plenty of space to fish over free stones covering mayfly nymphs. Other fishing areas -- the Blue Hole Pool behind the Darlington Fire Hall, the Sleepy Hollow crossing, Kingston Dam and pools near Rt. 30 pullovers -- were crowded, but Evancho reported few problems.

"I think a lot of guys saw the rain and decided to go to the lakes" instead of the streams, he said. "Donegal Lake -- I've never seen it so busy. There were probably 70 to 75 boats. But overall -- good weather, good water, people are happy. That makes my job easier."

Morning anglers in Washington County found a lot of fish in the creeks, and many limits were taken at Canonsburg Lake.

Armstrong County was hit or miss.

"It depends on where you are," said WCO Bruce Gundlach. "In Buffalo Creek they caught more fish than in other years, but Cowanshannock Creek was kind of muddy -- the headwaters are in farm land -- and they didn't catch a lot of fish there."

Cheery Run and South Fork Pine Creek were fishing below average despite good water conditions.

"The rain here didn't raise the stream levels much, if at all, but it clouded them up some," he said. "We went from crystal clear yesterday, which is not good, to slightly cloudy today, which is just right."

Beaver County didn't catch much rain, leaving creeks clear and low. A moderate number of limits were taken from the county's lakes, and catches were spotty in streams.

Angling pressure was off in Greene and southern Washington counties, where little rain fell. Stream action was good until about 10 a.m., said WCO Tom Crist, when "everything shut off."

Anglers were unusually happy with the size of trout pulled out of Indiana and eastern Armstrong county creeks, said WCO Matt Sodmont.

"Out at Plum Creek there were some big fish stocked and anglers were happy with what they were catching," he said. "This is the first opening day in seven years that they weren't complaining about size."

Two Lick Creek, he said, was fishing sluggishly early but picked up later in the day, and Yellow and Little Yellow creeks were, "phenomenal -- a lot of limits," said Sodmont.

"The water is a little stained, about perfect for fishing," he said. "You couldn't sight fish for big palominos, but the fish could see well enough."

In Fayette County, WCO Scott Opfer said Virgin Run is packed. He counted 719 anglers and 64 boats. Also crowded is the kids' area below the dam, where the Star Junction Fish and Game Club was giving out prizes and members helped young anglers bait their hooks.

"The only place that isn't crowded is the new kids' area on Dunbar Creek behind Dunbar Fire Hall," he said. "We put 400 fish in there last night, and there can't be more than 10 kids in there now. There are still a ton of fish in there for kids."

About 575 vehicles were counted at Laurel Hill State Park in Somerset County, where anglers were reeling in recently stocked trout.

In Allegheny County, Turtle Creek was fishing better than most streams. Angling pressure was moderate on Deer Lakes.

WCO Bob Wheeler said the best action was on Montour Run where the stocked area grew by more than a mile this year.

"On Wednesday, we put 3,000 fish in there, more than we put in last year," he said. "And on Friday a local angler group put in 200 fish over 18 inches. Word got out and there must have been 400 to 500 people in that four-mile stretch with a lot of limits taken."

On the limestone streams of Central Pennsylvania, fishing show promoter Chuck Furimsky said there were more anglers than expected, but fewer fish. At Bald Eagle and Spring creeks, the slightly high, clear water yielded a stonefly hatch, sizes 14-16, "but the fish weren't coming up for them," he said.

John Hayes can be reached at jhayes@post-gazette.com or 412-263-1991.