Following the comment of IC_designer_Rimpelbekkie is the path you want to take. Jitter will manifest itself in the spectral domain as a "skirt" around your desired frequency. An estimate formula of the Noise-to-Carrier Ratio depends inversely on the quality factor squared of your LC tank which again scales inversely with your ppm, thereby: Noise-to-Carrier Ratio ~ ppm^2.
Next, we can safely assume that the jitter can be modelled by a Gaussian Stochastic Process, as it is essentially a contribution of a number of thermal noise sources associated with resistances, resistive channels of MOSFETs, shot noise e.t.c.
Lastly we know that the autocorrelation function is linked to the power spectral density by means of fourier transform. We may therefore be able to estimate the standard deviation!
Deviation of Jitter ~= sqrt(Integrate(ppm^2 * Peak_Value / w^2)).
Edit 1: The integrand, as presented above, is wrong. What I meant was the peak value at the origin, and then decreasing by w^2 around it. Evaluating this expression yields: ppm * sqrt(2*Peak_Value_of_Noise_to_Carrier_Ratio)
Edit 2: Plugging in actual numbers: 50 ppm, -100dBc Noise to Carrier: 0.707 ns. Can anybody comment on whether this seems reasonable?