James Callahan, proceeding pro se, appeals the dismissal without prejudice of his 42 U.S.C. § 1983 complaint as not ripe for review. Although he renews the allegations of his complaint, Callahan does not challenge the district court’s conclusion that any relief would be uncertain and speculative at this time.
By failing to brief any argument challenging the reasons for dismissal, Callahan has abandoned the only grounds for appeal. See Yohey v. Collins, 985 F.2d 222, 224-25 (5th Cir.1993); Brinkmann v. Dallas County Deputy Sheriff Abner, 813 F.2d 744, 748 (5th Cir.1987). The appeal is without arguable merit and is therefore dismissed as frivolous. See 5th Cir. R. 42.2; Howard v. King, 707 F.2d 215, 219-20 (5th Cir.1983). Callahan is warned that future frivolous filings will invite the imposition of sanctions.
APPEAL DISMISSED; SANCTION WARNING ISSUED.