A high-resolution convection-permitting ensemble-based data assimilation and numerical weather prediction system is used to explore the predictability limit of severe thunderstorms and the possibility to improve their current predictions. It is found that the evolutions of severe thunderstorms can be drastically changed in 3 to 6 hours even the initial differences are smaller than the detection capabilities of current observation platforms. Those minute differences will be propagated and evolved via turbulence and rapidly amplified in moist convective processes through interactions between updrafts and cold pools. Aside from observations from Doppler weather radars that have been proven to be valuable in severe thunderstorm prediction with ensemble-based data assimilation techniques, the new-generation geostationary weather satellites also provide an opportunity to further improve severe thunderstorm prediction, even before them being observed by the radars.