  A modified version of the conditional symmetry method, together with the
classical method, is used to obtain new classes of elliptic solutions of the
isentropic ideal compressible fluid flow in (3+1) dimensions. We focus on those
types of solutions which are expressed in terms of the Weierstrass P-functions
of Riemann invariants. These solutions are of special interest since we show
that they remain bounded even when these invariants admit the gradient
catastrophe. We describe in detail a procedure for constructing such classes of
solutions. Finally, we present several examples of an application of our
approach which includes bumps, kinks and multi-wave solutions.
