KCAL-TV meteorologist Alissa Carlson appeared Tuesday on “CBS Mornings” to explain why she fainted on air over the weekend.Carlson, who is also a health coach, revealed she checked into the hospital following her loss of consciousness while trying to give a weather report. She said though she has a history of fainting she had been worried she might be having a heart attack but that medical tests revealed it wasn’t heart-related. Instead, she said, it was related to a previous diagnosis of vasovagal syncope.