GRAINS-Corn, soy, wheat futures rise as U.S. crop belt heats up

* New-crop December CBOT corn contract sets 1-year high

* Hot spell hits western Midwest as corn begins pollination

* Soybeans hit four-month top, wheat up sharply too

(Recasts; updates prices, adds quotes, changes byline, changes dateline from previous PARIS/SYDNEY) CHICAGO, July 10 (Reuters) - U.S. corn and wheat futures rose more than 2 percent on Monday, with corn setting a one-year high on worries about forecasts for potentially stressful heat in parts of the Midwest. Chicago Board of Trade wheat futures climbed nearly 3 percent, led by outlooks for more hot and dry weather in the northern Plains spring wheat region. As of 12:11 p.m. CDT (1711 GMT), CBOT September corn futures were up 8-1/2 cents at $4.01 per bushel, with new-crop December corn up 9 cents at $4.13-3/4 after reaching $4.15, its highest since June 2016. CBOT August soybeans were up 25-1/4 cents at $10.26-1/4 after setting a four-month high at $10.29-1/2. CBOT September wheat was up 15 cents at $5.50 a bushel while Minneapolis Grain Exchange (MGEX) September spring wheat was up 26 cents at $7.92-3/4 a bushel. Corn and soybeans firmed on fears that rising temperatures this week and dry conditions in parts of the western Midwest could curb yield prospects. Corn in the heart of the Midwest is particularly vulnerable to weather stress this month during pollination, its key reproductive phase. Based on historical trends, the U.S. Department of Agriculture in May projected the 2017 U.S. corn yield at 170.7 bushels per acre. But some analysts think the this season's yield ultimately could fall short. "It is possible that we could stress the crop enough to produce a sub-160 bushel per acre crop," INTL FCStone chief commodities economist Arlan Suderman said in a note to clients. The USDA is scheduled to release updated monthly supply/demand reports on Wednesday, although typically the government waits until August to revise its corn and soy yield forecasts. Ahead of its weekly crop progress report due later on Monday, analysts expected the USDA to lower its condition ratings for corn, soybeans and spring wheat. Traders also appeared to be covering short positions in corn and soy. Weekly commitments data from the U.S. Commodity Futures Trading Commission on Friday showed speculators held larger-than-expected short positions, Suderman said, leaving those markets vulnerable to bouts short-covering. MGEX spring wheat futures led CBOT wheat higher on forecasts for more sizzling temperatures in the northern U.S. Plains.

CBOT prices as of 12:10 p.m. CDT (1710 GMT):

Net Pct Volume Last change change CBOT wheat WU7 550.75 15.75 2.9 70618 CBOT corn CU7 401.25 8.75 2.2 180364 CBOT soybeans SQ7 1027.50 26.50 2.7 37579 CBOT soymeal SMQ7 339.20 8.50 2.6 18290 CBOT soyoil BOQ7 33.74 0.89 2.7 25045

NOTE: CBOT September wheat, September corn and August soybeans shown in cents per bushel, August soymeal in dollars per short ton and August soyoil in cents per lb.

(Additional reporting by Gus Trompiz in Paris and Colin Packham in Sydney; editing by Christian Schmollinger and Alexander Smith)