I wouldn't let not having a partner stop you for one minute, but that's a personal opinion. I'm a solo chaser, nine years, 10 states later, not too many scary situations to report, although there have been exceptions, mainly due to human interference and being female (a few run-ins, men who wanted to cause trouble/got chased last year), but that's just one of the hazards to deal with so I have to extra pay attention. It's just like wildlife photography, same thing, you have to watch what's going on.
Solo chasing is my method because of two reasons: I travel long distances at a time, and move from point to point rapidly while shooting.
I'll take a reporter once in awhile but honestly, less photography gets done on those chases, but it is still enjoyable, just a different kind of experience.
Best situation for me in the Plains - just Kansas & I, we get a lot done. I'm half obsessed with Kansas anyway and love to spend time there in the open. In the desert, I chase alone too. It is quiet, I can concentrate, and go home at 4 o'clock in the morning, whenever the storms decide they are finished for the night and I have done my day's (or night's) work worth of shooting.
Once or twice I have teamed for a chase in the Plains or in a caravan, far less gets done in a caravan, but it is fun when good friends are about in their vehicles too as you head toward a storm.
I have brought a friend maybe 5 times or so in the desert, pretty much all good experiences but impossible to coordinate during Monsoon so again, solo chasing is far more productive for me. I learned my lesson, back in 1997 I took some people one night, and my passengers did some really unsafe things and I was so concerned about their safety that it ruined the chase. It is very rare that I have passengers these days.