Just because its humid it doesnt mean there will be storms. You need a trigger. The trigger is the surface trough to the west. Its not that strong so not much is going on to far away from it. As for the uppers, as mentioned this morning we have a pretty warm airmass with a highs analysed by the BOM over us or just to our sth west up till at least 500hpa height. This means the flow over a huge chunk of the atmosphere is easterly (or thereabouts) pushing the storms westward. The most easterly developing lightning active shwr has been the one near Stawell. Ukmet did a pretty good job with today.