diff --git a/main.go b/main.go
index 2d26bb508..0b7f9c1d4 100644
--- a/main.go
+++ b/main.go
@@ -36,6 +36,17 @@ const (
 	envTmpLogPath = "TF_TEMP_LOG_PATH"
 )
 
+// ui wraps the primary output cli.Ui, and redirects Warn calls to Output
+// calls. This ensures that warnings are sent to stdout, and are properly
+// serialized within the stdout stream.
+type ui struct {
+	cli.Ui
+}
+
+func (u *ui) Warn(msg string) {
+	u.Ui.Output(msg)
+}
+
 func main() {
 	os.Exit(realMain())
 }
@@ -82,11 +93,11 @@ func realMain() int {
 }
 
 func init() {
-	Ui = &cli.BasicUi{
+	Ui = &ui{&cli.BasicUi{
 		Writer:      os.Stdout,
 		ErrorWriter: os.Stderr,
 		Reader:      os.Stdin,
-	}
+	}}
 }
 
 func wrappedMain() int {
diff --git a/main_test.go b/main_test.go
index 406195e8b..9b9594f10 100644
--- a/main_test.go
+++ b/main_test.go
@@ -264,3 +264,20 @@ func (c *testCommandCLI) Run(args []string) int {
 
 func (c *testCommandCLI) Synopsis() string { return "" }
 func (c *testCommandCLI) Help() string     { return "" }
+
+func TestWarnOutput(t *testing.T) {
+	mock := cli.NewMockUi()
+	wrapped := &ui{mock}
+	wrapped.Warn("WARNING")
+
+	stderr := mock.ErrorWriter.String()
+	stdout := mock.OutputWriter.String()
+
+	if stderr != "" {
+		t.Fatalf("unexpected stderr: %q", stderr)
+	}
+
+	if stdout != "WARNING\n" {
+		t.Fatalf("unexpected stdout: %q\n", stdout)
+	}
+}