After an initial drenching Tuesday and Wednesday, forecasters are predicting a warm, dry Thanksgiving in Grass Valley. “The main thing to keep a heads up on is we are going to have another round of rain coming through,” said Brooke Bingaman, a forecaster with the National Weather Service in Sacramento. “The good news is that it will start clearing up Wednesday evening and hopefully be dry for Thanksgiving morning and during the day.” Showers are expected to begin today with the bulk of the heavy rainfall happening between tonight and Wednesday morning, Bingaman said. “The heaviest rain will be happening …