Computation of propagation effects in the neutral atmosphere, namely
path delay, extinction, and bending angle is a trivial task provided the 
4D state of the atmosphere is known. Unfortunately, the mixing ratio of water
vapor is highly variable and it cannot be deduced from surface measurements.
That fact led to a paradigm that considers path delay and extinction in
the atmosphere as a~priori unknown quantities that have to be evaluated 
from the radio astronomy data themselves. Development of our ability to
model the atmosphere and to digest humongous outputs of these models that
took place over the course of the 21st century changed the game. Using the 
publicly available output of operational numerical weather model GEOS
run by NASA, we are in a position to compute path delay through the neutral 
atmosphere for any station and for any epoch from 1979 through now with 
accuracy of 45 ps $*$ cosec elevation. We are in a position to compute 
extinction with accuracy better than 10 pro cents. We are in a position 
to do it routinely, in a similar way how we update apparent star positions 
for  precession and nutation. Moreover, we are in a position to do it now.
As a demonstration of current capabilities, I have computed time series of
path delays for all radiotelecopes that I was aware of (220 sites) since 1979 
with a step 3-6 hours. Results of the validation tests are presented. A new 
paradigm of data analysis assumes that we know the atmosphere propagation 
effects a priori with the accuracy higher that one could deduce them from 
radio astronomy observations.