Minor clarification to scenario modelling approach

doc/how-to/scenario-modelling.rst

@@ -27,7 +27,7 @@ Scenario modelling with pypfilt
 -------------------------------
 
 Scenario modelling is straightforward to implement in pypfilt.
-The key is to use the model prior distribution to characterise each scenario.
+The key is to use different model prior distributions to characterise each scenario.
 
 - Implement a simulation model (see, e.g., the :ref:`tutorial example <lorenz63-model>`).