I.R.C. Section 6323 provides that a federal tax lien shall not be valid as against a judgment lien creditor until notice of the federal tax lien is filed in the state clerk of superior court's office in the county where the real property is located. However, there is an exception. Where notice of the federal tax lien and a competing judgment lien simultaneously attach to after acquired real property of the tax payer, the federal tax lien prevails. United States v. McDermott, 113 S. Ct. 1526, 123 L. Ed. 2d 128 (1993).