Place full-page figure float after the page where it's referenced

Question

I have a document with a float figure that occupies the whole page. I want the float page to appear after the page where it is referenced first time. I also want the referring page to be filled with text to the bottom. For example if the reference is on page n, the figure should be on page n+1. If I insert the figure as "\begin{figure}" or "\begin{figure}[p]" the figure is placed on page n+2. How can I move it to page n+1?

Here's an MWE:

\documentclass[12pt]{article}
\pagestyle{plain}
\usepackage{calc}
\usepackage[english]{babel}
\usepackage[pangram]{blindtext}
\usepackage{caption}
\usepackage{floatrow}
\usepackage{afterpage}
\setlength{\textfloatsep}{20pt}
\setlength{\intextsep}{20pt}

\begin{document}
\vspace*{0.9\textheight}

\blindtext[40]

\blindtext[12]\textbf{(See Figure \ref{Fig1})} \blindtext[12] 

\begin{figure}[p]
\noindent \centering{}\ffigbox[\FBwidth]{%
\framebox{\begin{minipage}[t][0.8\textheight]{0.8\textwidth}%
\hspace*{\fill}%
\end{minipage}}}{\caption{\label{Fig1}This is figure 1. \blindtext[8]}}
\end{figure}

\blindtext[50] \textbf{(See Figure \ref{Fig2})}. \blindtext[10]

\begin{figure}
\ffigbox[\FBwidth]{%
\framebox{\begin{minipage}[t][3cm]{0.8\textwidth}%
\hfill{}%
\end{minipage}}}{\caption{\label{Fig2}This is figure 2. \blindtext[4]}}
\end{figure}

\blindtext[6] \textbf{(See Figure \ref{Fig3})} \blindtext[3] 

\begin{figure}
\noindent \centering{}\ffigbox[\FBwidth]{%
\framebox{\begin{minipage}[t][0.3\textheight]{0.8\textwidth}%
\hspace*{\fill}%
\end{minipage}}}{\caption{\label{Fig3}This is figure 3. \blindtext[2] }}
\end{figure}

\end{document}

And the output:

Answer 1

An alternative to Werner's solution would be to insert the figure environments immediately after the reference, instead of after several more lines of text. For example:

\blindtext[12]\textbf{(See Figure \ref{Fig1})}
\begin{figure}[tbp]
\noindent \centering{}\ffigbox[\FBwidth]{%
\framebox{\begin{minipage}[t][0.8\textheight]{0.8\textwidth}%
\hspace*{\fill}%
\end{minipage}}}{\caption{\label{Fig1}This is figure 1. \blindtext[8]}}
\end{figure}
\blindtext[12]

works with tbp placement or just p placement.

Answer 2

The basic problem here is that you insert a whole bunch of text after the reference using \blindtext:

...
\blindtext[6] \textbf{(See Figure \ref{Fig3})} \blindtext[3]
...

This could imply that the actual float insertion could happen far beyond your reference. Instead, you can use the following generic approach:

...
<reference>
\afterpage{
  <figure>
}
...

where <figure> uses the [H] float specifier in order to be placed exactly where it is called. Here is your minimal example, adjusted using the above suggestions:

\documentclass[12pt]{article}
\usepackage[english]{babel}
\usepackage[pangram]{blindtext}
\usepackage{caption}
\usepackage{floatrow}
\usepackage{afterpage}
\setlength{\textfloatsep}{20pt}
\setlength{\intextsep}{20pt}

\begin{document}
\vspace*{0.9\textheight}

\blindtext[40]

\blindtext[12]\textbf{(See Figure \ref{Fig1})}

\afterpage{%
  \begin{figure}[H]
    \centering
    \ffigbox[\FBwidth]{%
      \framebox{\begin{minipage}[t][0.8\textheight]{0.8\textwidth}%
      \hspace*{\fill}%
    \end{minipage}}}
    {\caption{\label{Fig1}This is figure 1. \blindtext[8]}}
  \end{figure}
  \clearpage
}

\blindtext[12]
\blindtext[50] \textbf{(See Figure \ref{Fig2})}.

\afterpage{
  \begin{figure}[H]
    \ffigbox[\FBwidth]{%
    \framebox{\begin{minipage}[t][3cm]{0.8\textwidth}%
    \hfill{}%
    \end{minipage}}}
    {\caption{\label{Fig2}This is figure 2. \blindtext[4]}}
  \end{figure}
  \clearpage
}

\blindtext[10]
\blindtext[6] \textbf{(See Figure \ref{Fig3})}

\afterpage{
  \begin{figure}[H]
    \centering
    \ffigbox[\FBwidth]{%
      \framebox{\begin{minipage}[t][0.3\textheight]{0.8\textwidth}%
      \hspace*{\fill}%
    \end{minipage}}}
    {\caption{\label{Fig3}This is figure 3. \blindtext[2] }}
  \end{figure}
  \clearpage
}

\blindtext[3]

\end{document}

The addition of \clearpage ensures that only that specific figure is placed on the page.