On modern versions on Android (9+), it is possible for you to configure your device's settings to allow SW+ Alerts audio notifications to override Do Not Disturb when it's activated. (This does not apply to silenced devices.)
From within the StormWatch+ app with an active subscription to SW+ Alerts, tap the Settings button on the Active Alerts card.
Tap "Send Test Notification," which should test your device to make sure your settings are correct and send you a test push notification. On the bottom of that test screen, tap "Go To Settings App."
This takes you to your phone's settings for the StormWatch+ app.
You should see your device's app notifications options for StormWatch+. Tap "SW+ Alerts: Wake Me Up alerts" and scroll to the bottom. You will see "Ignore Do Not Disturb." Turn this ON.
Wake-me-up alerts sent by SW+ Alerts will now sound even if Do Not Disturb is activated on your device.