Yes that's perfectly normal. My Gray Tree Frogs get very excited during Thunderstorms but even just when it rains without the lightning. Their excitement isn't from stress though, they clearly enjoy being near the window with the panes opened so they can feel the change in pressure, humidity etc. My guess from a lot of observation of Toads here is that she's only stressed by the fact that she can't get to a suitable spot from which to observe the storm as my wild resident Toads do during the storms here.