How to send data from ThingSpeak to ESP-8266 (Arduino) using ThingHTTP?
For sending information to/from Arduino best option is MQTT. It's lightweight and very simple to use.

While your Arduinos are using MQTT to send info and receive commands (like changing thresholds), your Web server has access to the same information in real time. You can format it and present it in any way you like, without any Arduino participation.