quando si dice outflow boundary....

[miki]

Actually that is not a clear outflow boundary. At first it is an outflow boundary from those few storms in delta Po (few scans), but later its obvious the converging line of cumulus comes by the wind from the Adriatic sea (sea breeze) which is stronger in April than usually during summer due to big temprature difference between near surface layers over Adriatic and over Po valley. Thats why it gets deeper across the Po valley towards the NW, as seen on the satellite. You can notice it all along the Italian coast from south Friuli down to almost Rimini... and it often gives similar Temp/Rh graphs like the one posted above.

These two things can get mixed sometimes as its becomes tricky to determine both

I completely disagree with you...
The inland boundary of the sea breeze it's clearly visible during the whole satellite loop and it remains stationary at about 8-10 miles far from the coast. Why should sea breeze gain hundred of miles inland only (only!) near central "Pianura Padana" and not in Northern Veneto or in Romagna?
Even the speed of that "mesoscale front" is not compatible with sea breezes' one... Too fast!
Finally, it is true that sea breezes are relatively strong during this season, but not so much!