Hereâs why I chose the NASM certification! Did you need any sort of background related to the field going into the program? Nope, you just need to make sure that you have a current CPR and AED certification before you take the exam. How long does your certification last before you have to renew it?
Tornado Warning. This is issued when a tornado is indicated by the WSR-88D radar or sighted by spotters; therefore, people in the affected area should seek safe shelter immediately. They can be issued without a Tornado Watch being already in effect. They are usually issued for a duration of around 30 minutes.
Using a new kind of weather radar, meteorologists can detect a tornado as it's forming--up to 20 minutes before it touches down! With conventional radar, they usually could only detect a tornado only after it had formed. The tornado would appear as a hook echo on the radar return. This also wasn't reliable so forecastors had to rely on spotter reports. The new radar gives forecastors the lead time they need to issue a tornado warning early enough that the public can seek shelter.