I imagine the @WFstaff Team has secretly come up with a better name for Tempest without realizing it was right in front of them.
Look at it this way:
The Smart Weather System has three devices that make up the entire weather system. SKY, AIR, and Hub. The serial number for each device has the reference of the device names within the number.
Hub = HB-000*****
AIR = AR-000*****
SKY = SK-000*****
The Tempest System has two devices that make up the entire weather system. Tempest and Hub. It follows the same pattern with the serial numbers except for Tempest.
Hub = HB-000*****
Tempest = ST-000*****
Notice the ST in the Tempest serial number. Without any doubt, WeatherFlow has a specific reason for using ST in the serial number. But, if you are looking for a name that is weather-related and falls in line with SKY & AIR and is just as simple, then look no further than STORM. Therefore, you would have a weather-related name like SKY and AIR. Plus, it already matches the serial number.
Hub = HB-000*****
Storm = ST-000*****
Storm just seems obvious to me.