L.

Just taking another look at this moth. When I look at the BOLD image of grotei it shows a brownish hindwing with a pale line similar to the one in my photo. And since BOLD mentions it has been sited in the western states such as Washington, maybe this would be it??

Haven't seen either grotei or signatalis personally, but they're very similar. I think signatalis may be more likely, given paler forewing colour and presence of AM line - see below.

Powell and Opler (Moths of Western North America) say that P. grotei has a deep purplish pink FW, "lacks the antemedial line, and the postmedial is indicated by a wedge at the costa and sinuate broken line". P. signatalis is bright rose pink and the PM line curves and zigzags.

Realise the PM comments aren't clear for yours, but it does have an AM line like signatalis. The lack of an AM line in grotei appears to be borne out by photos on MPG and on BG (other than the two you posted recently on BG). Your photo also looks very similar to Mark Dreiling's P. signatalis on MPG which has DNA confirmation.

The new BC list (2015) also lists P. signatalis but not P. grotei, although I realise that doesn't necessarily rule out grotei in either BC or WA!

Probably never know without DNA. Could it be that the two are the same species? I have seen several of these in Swakane Canyon and some have pale forewings and some are deeply colored. Or maybe both species can live in the same area.

Don't know whether we'd know for sure without DNA or dissection by someone who can do it.

it does look like Pyrausta signatalis. Hmm.