Opponents of Washington’s new high-earners income tax said Tuesday they’ll start gathering signatures for an initiative to repeal it this fall. To qualify for the November ballot, foes of the tax will need to gather 308,911 signatures from voters by July 2. To make up for invalid or duplicate signatures, the secretary of state’s office advises gathering closer to 400,000. In a news release, leaders of Let’s Go Washington , the conservative group leading the anti-tax charge, said they’re confident they can meet reach that goal despite the short time frame. “The voters in this state have rejected the income tax numerous times and we’ve had thousands of people reach out to help us repeal the income tax,” said Brian Heywood, the Redmond hedge fund manager who heads Let’s Go Washington. The initiative Heywood said the group will back was filed in April by Chantell Mellott, a North Bend resident.…