Is there a way to get notification for High priority task

You may consider creating a query and putting a widget in the dashboard.

You could develop a follow-up action that adds subscribers to work items based on certain criteria. For example, we developed one that we called "Set Subscribers from Filed Against". In our follow-up action, we allow the operation behavior to be configured so you can specify a Filed Against value and an associated user. When work items are filed against that category, the designated user is automatically subscribed to the work item. They then get e-mail notifications based on their existing subscription notification settings. For your scenario, you could take a similar approach based on priority or severity instead of Filed Against.