The sodden conditions that put a damper on opening weekend of AirVenture, the Experimental Aircraft Association’s typically jam-packed annual fly-in, are likely to continue for another day or so. But sunny skies are predicted beginning Wednesday afternoon, a forecast that should help brighten spirits in Oshkosh, Wis., where thousands are expected for the world’s largest air show.

Wittman Regional Airport, temporary home to as many as 5,000 general aviation aircraft that are flown in for EAA’s annual AirVenture event, had fewer than 1,200 aircraft tied down in grass parking areas by Monday afternoon, Dick Knapinski, EAA’s director of media and public relations, told Aviation Week. Recent torrential rains that ended last Saturday had left most grass parking areas so waterlogged that event organizers had to turn away most arriving aircraft for the past three days.

Many aircraft arriving at Oshkosh last Saturday and Sunday were diverted to neighboring airports at Fond du Lac and Appleton, although Knapinski could not estimate how many aircraft were still parked at those airports, among other nearby landing facilities. He declined to estimate how many of those aircraft might return to Oshkosh as weather conditions improve and how many pilots might return to their home airports instead.

Drive-in visitors still were arriving in large numbers, but several camping and RV parking spots in EAA’s Camp Scholler, south of the EAA Museum, were so saturated that some campers and RVs were being temporarily turned away. Over the past weekend, several shopping parking lots in Oshkosh were brimming with RVs waiting for camping slots at the airport.

“I’ve been involved with EAA for 35 years and this is by far the most challenging AirVenture we’ve experienced,” said Tom Poberezny, EAA president and chairman. “This is a little like going into the ring with Ali or Frazier,”

Grass parking areas are drying out, such as the North 40 adjacent to Runway 9/27 and the Vintage Parking area west of Runway 18/36, enabling the airport to accommodate more arriving aircraft. More campers and RVs were rolling into Camp Scholler on Monday afternoon.

But rain-soaked vehicle and airplane parking areas caused a large number of visitors to miss the opening day of AirVenture 2010 and perhaps the entire event. As a result, overall attendance at this year’s EAA AirVenture may fall short of 2009 levels.

The National Weather Service is calling for isolated thunderstorms in the area Tuesday followed by heavy rain tonight and a 40% chance of more thunderstorms Wednesday morning. But conditions should clear after that. This year’s AirVenture ends Sunday, Aug. 1.

Tom Poberezny photo: EAA