UPDATE 2-Weather forecast cools U.S. natgas futures to 3-mnth low

* Milder weather predictions pressure prices * Texas and the South expect warm mid- to late-June * Coming up: EIA's short-term energy outlook Tuesday By Joe Silha NEW YORK, June 10 (Reuters) - U.S. natural gas futures reversed course and headed lower on Monday, with the front contract driven to a three-month low after computer weather models took some of the heat out of the extended forecast. "The noon weather model runs are trickling in, and it looks like we're going to se