这可能有效（需要添加到模型规则中）

array('startDate', 'compare', 'compareValue' => date("Y-m-d"), 'operator' => '>'),

$date_today          = date('Y-m-d', strtotime(' -1 day')); 
                           // -1, -2 depend on how back you want to go!!
  $date_today          = date("m/d/Y", strtotime($date_today));

   return [   
        [
          'alert_start_date', 'compare', 'compareValue' => $date_today, 
                                                 'operator' => '>',   
          'message' => $attribute.'Alert Start Date Cannot be a date in the past'
        ], 
    ];