The phrase "however thereafter" is correct and usable in written English.
It is a subordinating conjunction used to connect two independent clauses, showing contrast between them. For example: I wasn't feeling well earlier, however thereafter I felt much better.
However, thereafter, the gas production rates differ significantly.
However, thereafter along with the development of technology, it have been seen that the ordinary differential equations cannot respond to the needs arising in sciences and engineering.
However, thereafter, the storm began weakening as a short-wave trough in the westerlies moved into northern Mexico, which caused increased wind shear on Tropical Storm Fefa.
However, thereafter male mating rate declined significantly and considerably (Fig. 2B).
However, thereafter the efficacy against clinical malaria wanes (the evaluation of the proportionality of the hazard assumption reveals that the efficacy in cohort 2 changes with time) and there was no difference in the risk of malaria between RTS,S/AS02A and control recipients during the single-blind phase.
However, thereafter, diabetes became a risk factor.
However, soon thereafter, power cables became the commonly accepted means of transporting electricity across distances.
However, shortly thereafter his poll numbers began to wane, partly because of a series of gaffes.
However, soon thereafter his campaign began to struggle when questions mounted concerning his grasp of foreign policy.
However, shortly thereafter he was re-charged, and in March he was found guilty of having illegally arrested the criminal court judge.
However, shortly thereafter Volkswagen faced a public relations crisis when the U.S. Environmental Protection Agency EPAA) determined that the manufacturer's diesel-powered cars contained software that altered the vehicle's performance in order to pass emissions tests.
