  In this contribution, we present the most recent progresses we obtained in
the context of a long-term program we undertook since a few years towards the
implementation of operational forecast systems (a) on top-class ground-based
telescopes assisted by AO systems to support the flexible scheduling of
observational scientific programs in night as well in day time and (b) on
ground-stations to support free space optical communication. Two topics have
been treated and presented in the Conference AO4ELT6:
  1. ALTA is an operational forecast system for the OT and all the critical
atmospheric parameters affecting the astronomical ground-based observations
conceived for the LBT. It operates since 2016 and it is in continuous evolution
to match with necessities/requirements of instruments assisted by AO of the LBT
(SOUL, SHARK-NIR, SHARK-VIS, LINC-NIRVANA,...). In this contribution, we
present a new implemented version of ALTA that, thanks to an auto-regression
method making use of numerical forecasts and real-time OT measurements taken in
situ, can obtain model performances (for forecasts of atmospherical and
astroclimatic parameters) never achieved before on time scales of the order of
a few hours.
  2. We will go through the main differences between optical turbulence
forecast performed with mesoscale and general circulation models (GCM) by
clarifying some fundamental concepts and by correcting some erroneous
information circulating recently in the literature.
