Showing and hiding a card with a web call

Configuration
1

Hopefully the title is right.

I would like to create a banner like card that would appear when there is a sever weather alert for our area.

I was thinking of using IFTTT to make a web call to HA and then have the banner appear with the alert.

I don’t even know where to start with this one so if there is something for me to read first, please point the way!

Thanks

2

I think you can use a sensor (based on IFTTT web call) and conditional card to hide/display any card you want. To show the card as a banner (full width), you’ll have to set the view with panel: true and the conditional card as the 1st card if you want it on top.

My banner can be combined with conditional card as an example.