Drier weather in the U.S. Midwest this weekend and early next week will lead to a sharp boost in corn planting, which has fallen to the slowest pace in nearly three decades, an agricultural meteorologist said on Thursday.

"Showers will scatter from the central into the eastern Midwest and Delta during the next two days, with a break of five days ahead of the next chance of rain...," said Commodity Weather Group (CWG) meteorologist Joel Widenor.

Widenor said some planting was taking place this week in several areas of the Midwest, but full-scale seeding would not begin until the weekend. Another round of showers is expected beginning next Wednesday, again slowing corn planting, he said.

"The 11-to-15-day forecast (May 20-24) leans wetter as well and will cause widespread interruptions to seeding in the Midwest," Widenor said.

Stalled by rain and late-season snow in the last week, U.S. farmers had planted just 12 percent of their intended corn acres as of Sunday, the slowest pace since 1984, the U.S. Department of Agriculture said in a weekly report on Monday.

Soybean planting was 2 percent complete by Sunday, tied with 1983 and 1993 for the second-slowest place by early May, following the 1984 record of 1 percent.

The five-year average for planting progress at this time of year is 47 percent for corn and 12 percent for soybeans.

Producers working fields in the heart of the U.S. Corn Belt were interrupted by storms at mid-week.

Seeding progress fell short of trade expectations, including a Reuters poll of 14 analysts ahead of USDA's report that pegged corn planting at 15 percent complete.

(Reporting by Sam Nelson; Editing by John Wallace)