(Adds closing prices, analyst quote)
By Mark Weinraub
CHICAGO, April 26 (Reuters) - U.S. soybean and corn futures firmed on Tuesday, their second straight day of gains, on expectations the pace of planting will slow in coming days due to wetter weather.
"Tractors could stall quickly as more rains move into the Midwest this week," Farm Futures senior grain market analyst Bryce Knorr, said in a note to clients.
Wheat futures also rose for the second day in a row as traders covered short positions despite a bearish fundamental picture amid signs of good crop development and weak export prospects.
Chicago Board of Trade May corn futures settled up 5-1/4 cents at $3.82-1/4 a bushel. CBOT May soybeans were 18 cents higher at $10.17-3/4 a bushel.
"A wetter bias is forecast for much of the Midwest later this week to cause interruptions to fieldwork," said Tobin Gorey, director of agricultural strategy at Commonwealth Bank of Australia.
Soybeans gained more ground as funds continued to buy agricultural commodities on worries over South American supply.
The U.S. Agriculture Department said on Monday afternoon that 30 percent of the U.S. corn crop has been planted, in line with expectations but much higher than the five year average of 16 percent. Soybeans were 3 percent planted, also ahead of the five-year average.
"(The accelerated planting pace) is coming to a screeching halt with possible and probably delays," said Brian Hoops, president of Midwest Market Solutions, a brokerage and commodity marketing advisory service.
U.S. winter wheat was rated 59 percent good-to-excellent, up from 57 percent one week earlier, the USDA said. Analysts had expected wheat to be 58 percent good-to-excellent.
CBOT May soft red winter wheat futures ended up 8-1/2 cents at $4.79-3/4 a bushel.
Corn, soybeans and wheat all settled near their session highs but were still well below multi-month peaks reached last week. Many investment funds viewed the retreat from the recent highs as a good technical buying opportunity, Hoops said. (Additional reporting by Sybille de La Hamaide in Paris and Naveen Thukral in Singapore; Editing by Andrew Hay and Chizu Nomiyama)