Naviga Mobile automated alert system handles severe weather events from the National Weather Service (NWS). Because we directly integrate with the NWS we can beat competitors to market with alerts - typically by 30 minutes or more.
End users of your app can subscribe to receive push notifications for one or more cities. Said another way, users choose the places they get alerts for, not you. For a walk through of this flow please check out our Integrated Weather article.
Once a weather alert is raised by the NWS for a subscribed location the end user will receive a push message, that when clicked will bring them into the app to a weather alert landing page that looks like this:

Notice that the page nicely formats the typically cryptic summary text from the NWS. It also shows an outline of the impacted area, with quick links to jump to radar or weather pages.
What events are pushed
There are certain events that will show up as an item in-app, but do not warrant a push notification.
For example, we don't send push notifications for "severe weather statement", because it is just follow up to an already raised alert per http://www.weather.gov/bgm/severedefinitions.
Here are some other events we do not send push notification for (but do put the event in app):
'flood warning', 'high wind warning', 'severe weather statement', 'fire weather watch', 'red flag warning', 'excessive heat watch'
When an end user subscribes to a location, what are they subscribing to?
End users can search for cities and zip codes. The search result will translate to a city center (lat/lng) for the selected location. When the NWS raises an alert they target it for a combination of one or more of County/Parrish and/or Weather Zones (aka UGC). If the subscribed city center is inside one of these targets, the end user will be alerted.
I got an alert for an event that is really far from my subscribed location, why?
The NWS probably targeted your county instead of the smaller Weather Zone. Keep in mind some counties are huge.