XBT (eXpendable BathyThermographs) transect MX04 cross along the warmer and saltier part of the Mediterranean Sea waters, where some permanent and transient structures and gyres can be observed and monitored with the XBT data. Several studies have located in that region unexpected changes and unexplained variability since the 80's (for instance Malanotte-Rizzoli et al.,1999). The intrusion of seawater from eastern basin into western part is almost continuously monitored but not the region where such warm and salt water forms. In the past thirty years the traditional flow of water in the Mediterranean has been modified due to climate change: Mediterranean is still continuing to be warmer and saltier and the rise in sea level is accelerating in recent years. In the Mediterranean, reported temperature anomalies often locally translating into disruption of the wind regime, of the water mass stratification and of the thermocline depth, could in part be correlated with positive North Atlantic Oscillation.