Satellite thermal images (NOAA 9) of the St. Lawrence estuary are used to confirm the existence of a persistent cold spot due to tidal upwelling at the head of the lower St. Lawrence estuary and to show that cold water may be found episodically up to 100 km downstream of the head. This extended cold anomaly may exist in two spatial configurations: one confined to near the south shore, the other being centered over mid-estuary. We discuss the various physical agencies likely to contribute to the growth of this anomaly and conclude that wind, internal tides, and advection of cold water from the head region are the most significant. ¿ American Geophysical Union 1988