Not likely to see any effects on GPS. The small line you see in the graph is what happened during the previous 27 day rotation. Nothing happened then as far as I know.
The values that you see there are not really high anyway, beginning of April they where much higher.
If you look
here you will see the following:
Outlook For May 26-June 1 No space weather storms are expected.
I know that graphs can look scary sometimes, but this really is storm in a teacup.
ATCast