In “Future impact: Predicting scientific success“, Acuna, Allesina, and Kording predict the future h-index of scientist using their current h-index, the square root of the number of articles published, years since first publication, number of distinct journals, and the number of articles in top journals. They vary the coefficients of a linear regression with the number of years in the forecast and note that, in the short term the largest coefficient is (not surprisingly) the scientist’s current h-index, but in the long term, the number of articles in top journals and the number of distinct journals become more important for the 10 year h-index forecast. They achieve an $R^2$ value of 0.67 for neuro-scientists which is significantly larger than the $R^2$ using h-index alone (near 0.4).
Additionally, they provide an on-line tool you can use to make your own predictions.