\begin{equation}
Tl_{ref} = MAX(\, Tl_{ref-min}, \, MIN( \, Tl_{ref-max}, \, Tl \,) \,)
\end{equation}

\noindent where Tl$_{ref}$ is the long-term reference 2-meter temperature, 
Tl$_{ref-min}$ and Tl$_{ref-max}$ are the reference minimum and maximum
 long-term 2-meter temperature which CHECK should be set at the beginning of this 
subroutine, and Tl is the "long-term" 2-meter reference temperature, previously
calculated.

