The very warm and humid air mass of the past few days resembles a sauna, at least relative to this time of year. Its origin, as indicated by a wide band of clouds on the satellite imagery, originates near the Cape Verde Islands off the West African coast. Tropical indeed!
All that's needed to trigger heavier rains than we've already seen is a lifting mechanism. And that is coming in the form of a cold front from the northwest. This front is already in Huelva province, clearly delineated on the radar scope by moderate to heavy rains. So, be on the lookout this afternoon for this line of rain and thunderstorms.
We should finally see some clearing overnight.