According to two sources Reuter press agency reports that Tesla is already in the last phase of preparations for its fourth model Tesla Model Y. Unofficially Tesla's second and smaller crossover could be ready for production by November 2019.
Elon Musk announced already in February, that Tesla is preparing new crossover. After the Tesla Model 3 production finally started to reach 5.000 cars per month, they started to do talks with potential suppliers of new model's components. The production predictions are very ambitious with around half a million units produced just in first year. It's twice the predicted production of Model 3. For 2001 they plan to start production in new Chinese plant, which should contribute to the substantial increase of production.
Musk or Tesla Motors did not confirm or reject claims by Reuters. But judging to the past experience such plans seem very optimistic at best.