def draw_anal_visual_metagram(self, station_combo):
        model_name = "ANAL"
        ui = self.tab_ui[model_name]
        elem_name = ui['list'].currentItem().text()
        
        stat_name = station_combo.currentText()
        stat_lat, stat_lon = station_combo.currentData()
        
        combo = ui['init_combo']
        count = min(6, combo.count())
        
        # --- 修正箇所：初期値（None）の判定を追加 ---
        if count == 0 or combo.itemData(0) is None:
            QMessageBox.warning(self, "エラー", "データが存在しません。")
            return
            
        times = []
        vals = []
        u_vals = []
        v_vals = []
        
        for i in range(count - 1, -1, -1):
            it_str = combo.itemData(i)
            
            # --- 修正箇所：it_strがNoneの場合はスキップしてエラーを回避 ---
            if not it_str:
                continue
                
            dt_utc = datetime.strptime(it_str, "%Y%m%d%H%M%S")
            dt_jst = dt_utc + timedelta(hours=9)
            times.append(dt_jst)
            # -------------------------------------------------------------
            
            target_file = os.path.join(self.cache_dir, f"ANAL_{it_str}_FT00.npz")