  The double humped SED (Spectral Energy Distribution) of blazars, and their
flaring phenomena can be explained by various leptonic and hadronic models.
However, accurate modeling of the high frequency component and clear
identification of the correct emission mechanism would require simultaneous
measurements in both the MeV-GeV band and the TeV band. Due to the differences
in the sensitivity and the field of view of the instruments required to do
these measurements, it is essential to identify active states of blazars likely
to be detected with TeV instruments.
  Using a reasonable intergalactic attenuation model, various extrapolations of
the EGRET spectra, as a proxy for GLAST (Gamma-ray Large Area Space Telescope)
measurements, are made into TeV energies for selecting EGRET blazars expected
to be VHE-bright. Furthermore, estimates of the threshold fluxes at GLAST
energies are provided, at which sources are expected to be detectable at TeV
energies, with Cherenkov telescopes like HESS, MAGIC or VERITAS.
