My prediction
Labour back a bit
Tories making gains(2016 UKIP vote goes to them)
Plaid treading water
26 L
18 T
14 P
2 Libs/Abolish

Labour will gain Rhondda and hold Llanelli. May lose Vale and Bridgend to Tories.

On a broader point, Plaid may be making loads of noise but are not breaking through to the broader electorate and are being squeezed by both Lab and Tory.