This paper presents 28 GHz and 73 GHz empirically-derived large-scale and small-scale channel model parameters that characterize average temporal and angular properties of multipaths. Omnidirectional azimuth scans at both the transmitter and receiver used high gain directional antennas, from which global 3GPP modeling parameters for the mean global azimuth and zenith spreads of arrival were found to be 22° and 6.2° at 28 GHz, and 37.1° and 3.8° at 73 GHz, respectively, in non-line of sight (NLOS). Small-scale spatial measurements at 28 GHz reveal a mean cross-polar ratio for individual multipath components of 29.7 dB and 16.7 dB in line of sight and NLOS, respectively. Small-scale parameters extracted using the KPowerMeans algorithm yielded on average 5.3 and 4.6 clusters at 28 GHz and 73 GHz, respectively, in NLOS. The time cluster - spatial lobe (TCSL) modeling approach uses an alternative physically-based binning procedure and recreates 3GPP model parameters to generate channel impulse responses, as well as new parameters like the RMS lobe angular spreads useful in quantifying millimeter-wave directionality. The TCSL algorithm faithfully reproduces first- and second-order statistics of measured millimeter-wave channels.