The interplay between order and disorder in photonic lattices opens up a wide range of novel optical scattering mechanisms, cavity-mode resonances, and applications that can be obscured by typical ordered design approaches to photonics. Striking examples include Anderson localization, random lasers, and visible light scattering in biophotonic structures such as butterfly wings. In this work, we present a profound example of light localization in photonic crystal waveguides by introducing long-range correlated disorder. Using a rigorous three-dimensional Bloch mode expansion technique, we demonstrate how interhole correlations have a negative contribution to the total out-of-plane radiative losses, leading to a pronounced enhancement of the quality factor, Q, and Q/V cavity figures of merit in the long-range correlation regime. Subsequently, the intensity fluctuations of the system are shown to globally increase with the correlation length, highlighting the nontrivial role of long-range disorder on the underlying scattering mechanisms. We also explore the possibility of creating ultrahigh quality cavity modes via interhole correlations, which have various functionalities in chip-based nonlinear optics and waveguide cavity-quantum electrodynamics.