Although this thread is a little older, someone may be interested in my realization of NINA.
I made the NINA visualization for the available integration with a markdown card.
With this code I solved the problem with 5 sensors. They are all displayed in one card with a loop, separated by a horizontal line. The headlines are colorized according to the warning level.
If you like to ignore messages from dedicated sources like DWD you can add a variable which contains the attribute “sender” and a conditional line in the loop.
Instead of xxx in the code below fill in your selected sensor name without the index in the last character. The index is added from loop.index. The sensor name can be found in the developers section of HA.
Testing is possible if you do not block the covid messages in the integration. But of course you can choose a station with actual messages to test it, too.
Feel free to optimize it your way - and let me know 
type: markdown
content: |-
{% set ns = namespace() %}
<img src="/local/Nina_app.png" alt="Nina" width="45"/>
{% set ns.msg = false %}
{% for i in range(5) %}
{% set status = states("binary_sensor.warning_xxx_" ~ loop.index) %}
{% if(status == "on") %}
***
{% set ns.msg = true %}
{% set headline = state_attr("binary_sensor.warning_xxx_" ~ loop.index, "headline")%}
{% set description = state_attr("binary_sensor.warning_xxx_" ~ loop.index, "description") %}
{% set level = state_attr("binary_sensor.warning_xxx_" ~ loop.index, "severity")%}
{% set sent = state_attr("binary_sensor.warning_xxx_" ~ loop.index, "sent")%}
{% set start = state_attr("binary_sensor.warning_xxx_" ~ loop.index, "start")%}
{% set expire = state_attr("binary_sensor.warning_xxx_" ~ loop.index, "expires")%}
<font color=#000000>{{ sent }}</font>
{% if level == "Extreme" %}
**<font color=#ff0000>{{ headline }}</font>**
{% elif level == "Severe" %}
**<font color=#ffA500>{{ headline }}</font>**
{% elif level == "Moderate" %}
**<font color=#F6BE00>{{ headline }}</font>**
{% elif level == "Minor" %}
**<font color=#0000ff>{{ headline }}</font>**
{% else %}
**<font color=#000000>{{ headline }}</font>**
{% endif %}
<font color=#000000>{{ description | trim }}</font>
{% if start %}
*<font color=#666666>Begin: {{ start }}</font>*
{% endif %}
{% if expire %}
*<font color=#666666>Expires: {{ expire }}</font>*
{% endif %}
{% endif %}
{% endfor %}
{% if ns.msg == false %}
*<font color=#000000>No actual warnings.</font>*
{% endif %}
title: Nina
