Events and automations

The wxalerts_alert event

Every new hazard fires a wxalerts_alert event on the Home Assistant bus. The event data is the alert itself:

Trigger on the event, not the state

For warnings, the event is the better trigger, and the difference is not stylistic.

A state trigger fires on a transition. If a tornado warning is live for your county and the NWS issues a second one for a different storm, no entity changes: the binary sensor is already on, the severity sensor is already Extreme, the count goes 1 → 2 and back to 1 later. The event fires once per hazard, so the second warning announces itself.

It also stays quiet for the right things. An update to a hazard already in effect, whether a CON continuation or an EXT extension, reuses the same topic and fires no second event, so an hour-long severe thunderstorm warning does not re-notify you every time the office refreshes it.

State triggers are still the right tool for ambient things: a light that should be red while anything is live, a dashboard that shows the current severity.

A critical notification for a tornado warning

automation:
  - alias: Tornado warning, critical push
    triggers:
      - trigger: event
        event_type: wxalerts_alert
        event_data:
          event: Tornado Warning
    actions:
      - action: notify.mobile_app_phone
        data:
          title: "{{ trigger.event.data.headline }}"
          message: "{{ trigger.event.data.instruction }}"
          data:
            push:
              interruption-level: critical

Match on severity: Extreme instead of a specific event name to catch tornado emergencies and particularly dangerous situation warnings in one rule.

Announce it out loud, and light the house

automation:
  - alias: Warning announcement
    triggers:
      - trigger: event
        event_type: wxalerts_alert
    conditions:
      - condition: template
        value_template: "{{ trigger.event.data.severity in ['Extreme', 'Severe'] }}"
    actions:
      - action: light.turn_on
        target:
          entity_id: light.hallway
        data:
          color_name: red
          brightness_pct: 100
      - action: tts.speak
        target:
          entity_id: tts.piper
        data:
          media_player_entity_id: media_player.kitchen
          message: >-
            {{ trigger.event.data.event }} until
            {{ as_timestamp(trigger.event.data.ends) | timestamp_custom('%-I:%M %p') }}.
            {{ trigger.event.data.instruction }}

Ambient state: a light that follows severity

automation:
  - alias: Alert beacon follows severity
    triggers:
      - trigger: state
        entity_id: sensor.wxalerts_home_highest_severity
    actions:
      - choose:
          - conditions: "{{ states('sensor.wxalerts_home_highest_severity') == 'Extreme' }}"
            sequence:
              - action: light.turn_on
                target: { entity_id: light.alert_beacon }
                data: { color_name: red, effect: fast_pulse }
          - conditions: "{{ states('sensor.wxalerts_home_highest_severity') == 'Severe' }}"
            sequence:
              - action: light.turn_on
                target: { entity_id: light.alert_beacon }
                data: { color_name: orange }
        default:
          - action: light.turn_off
            target: { entity_id: light.alert_beacon }

Lightning: react to the rate, not the presence

A single flash 30 km away is not news. A count that climbs sharply is.

automation:
  - alias: Lightning closing in
    triggers:
      - trigger: numeric_state
        entity_id: sensor.wxalerts_home_lightning_flashes
        above: 20
        for: "00:02:00"
    actions:
      - action: notify.mobile_app_phone
        data:
          message: >-
            {{ states('sensor.wxalerts_home_lightning_flashes') }} flashes nearby in the
            last {{ state_attr('sensor.wxalerts_home_lightning_flashes', 'window_minutes') }}
            minutes. Bring the dog in.

Tune the threshold to your box size: 20 flashes in 15 minutes means something very different at 4.9 km than at 156 km. Watch the sensor through one storm season before trusting a number.

If you want the outdoor automations to stand down before the storm is genuinely gone, gate on last_flash rather than the count dropping to zero:

condition:
  - condition: template
    value_template: >-
      {{ (now() - (state_attr('sensor.wxalerts_home_lightning_flashes', 'last_flash')
         | as_datetime | default(now() - timedelta(hours=1)))).total_seconds() > 1800 }}

A Markdown card for live alerts

The alerts attribute is a full list, sorted most severe first, so one card renders whatever is live.

type: markdown
content: |
  {% set alerts = state_attr('sensor.wxalerts_home_active_alerts', 'alerts') %}
  {% if alerts %}
  {% for a in alerts %}
  ### {{ a.event }}
  **{{ a.severity }}** · until {{ as_timestamp(a.ends) | timestamp_custom('%a %-I:%M %p') }}

  {{ a.headline }}

  {{ a.instruction }}
  {% if not loop.last %}---{% endif %}
  {% endfor %}
  {% else %}
  No active alerts.
  {% endif %}

A map card with the hazards on it

type: map
entities:
  - zone.home
geo_location_sources:
  - wxalerts
hours_to_show: 0

Markers sit on each polygon’s centroid. To draw the real shapes, read the geometry attribute off a marker. It is full GeoJSON, live in the state machine.

Conditional card: only show weather when there is weather

type: conditional
conditions:
  - condition: state
    entity: binary_sensor.wxalerts_home_active_alert
    state: "on"
card:
  type: entities
  entities:
    - sensor.wxalerts_home_highest_severity
    - sensor.wxalerts_home_active_alerts
    - binary_sensor.wxalerts_home_tornado_alert