Slide 6 of 29
A westward traveling tropical wave manifests quite well on the lower atmosphere. In the absence of satellite imagery, RAOBS, ship synoptic and surface observations are the best tools for finding these perturbations.
Knowledge of climatology across the region is key for tropical wave detection, as shifts on the prevailing wind flow will be the first clue of an approaching tropical wave.
Over the eastern Caribbean, the prevailing easterlies will take a more NE component as a tropical wave approaches. As the wave axis moves over the area the easterlies will return, but as it passes the winds will take an ESE component.
Over the southeastern Caribbean the tropical waves are harder to find, as their circulation tends to be masked by the ITCZ anchoring low over the Gulf of Panama. Over Panama-Costa Rica the flow during the wet season has a NE component, except when a tropical wave moves west across the region inducing an ESE rotation of the mean flow. Strong waves can then draw the ITCZ north across Panama/Costa Rica into the southern Caribbean.