Materials undergoing phase transitions due to high cooling/compression rates may exhibit nonequilibrium effects, such as metastable phases. These inherently microscopic phenomena are complicated to capture in continuum-scale simulations due to the transient behavior along transition paths. However, metastable phase behaviors due to kinetic latency have significant effects on the material properties (e.g. compressibility or viscosity) and should therefore be considered in continuum models. We present a concurrent multiscale framework that uses molecular dynamics to directly inform large-scale simulations of the phase transition kinetics. Our approach interprets macroscopic inputs, such as energy and pressure, to microscopic system parameters and returns atomistic insights. In this work, the microscopic insight is provided as the rate of change of phase fractions. By comparing our work to conventional approaches such as Classical Nucleation Theory (CNT), we validate the work at equilibrium conditions and show that our approach advances the state-of-the-art for high cooling rates where nonequilibrium effects become increasingly important. When compared to full MD simulations, we show that artifacts such as finite-size effects can be mitigated using the new method. The novel method also provides a computational runtime improvement when compared to full MD simulations, with speedups of up to 25-fold. We end with a discussion on the potential limitations of the method. By coupling macroscopic observables to ’on-the-fly’ atomistic behavior, our method enables the resolution of complex material effects. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory (LLNL) under Contract No. DE-AC52-07NA27344, release number LLNL-ABS- 2015322.