Broadcast at swimming pool: "Thunderstorm warning is in force. For your safety, please get out of the water immediately..."
Friend A got out of the water, and call Friend B not to come.

Friend A: "Hi, there is now a Thunderstorm Warning. Don't come as the swimming pool here is closing."
Friend B: "My swimming pool is still open. Why not come and join me here!"
Friend A: "No way! Thunderstorm Warning is in force now."
Friend B: "Thunderstorm Warning is in force; but don't you know that there is regional information associated with the warning?"
Friend A: "What!?"
Friend B: "Just check the 'MyObservatory' app on your mobile phone. A red dot on the top right corner of the Thunderstorm Warning icon means that regional information is available. Click the icon and you’ll see a map showing regions affected by the Thunderstorm Warning."
Friend A took a look and said: "Oh, I see. No wonder the swimming pool on your side is still open, as the thunderstorms only affect isolated regions."
Friend B: "Check if there is any regional information associated with the thunderstorm arning before you go out for outdoor activities, and then you'll know if the activities can continue. In addition to this regional information, the 'MyObservatory' app also shows the latest lightning location. Lightnings only affect your district now, but not here. Come over!"