Pacific Earthquake and Tsunami

A relatively inactive cold front crossed the island late on Tuesday ushering temperatures closer to normal and much lower dew points that fell into the low 60s for a time. This was a welcome change following a spat of unusually warm and humid weather that had heat index values over 100F common during the peak of the day. That cooler drier post-frontal flow has since veered through north and northeast and has settled out of the east-southeast. This flow is allowing a slow increase in humidity and temperatures this weekend.

Additionally, a low over the Southwestern Atlantic is being monitored for tropical or subtropical development by the National Hurricane Center. As of 3pm local time, the NHC was giving this area a 40% chance for development in the next five days. At this time, it appears that this low will track slowly northeastward and track just offshore of the US East Coast over the next five days. This is currently a low confidence situation on whether or not something (sub)tropical forms, and where the area of unsettled weather goes regardless of formation. Updates from the National Hurricane Center and the Bermuda Weather Service should be monitored for the latest official information on this system.

Elsewhere in the Atlantic, weak Tropical Depression 9 is tracking northwestward over the Central Atlantic, where it is expected to become a remnant low in the coming days. Following closely behind is Tropical Depression 10, which formed this morning. TD10 is expected to fare somewhat better than TD9 as it tracks generally west-northwestward into the Central Atlantic. TD9’s deep convection and has somewhat moistened the environment around TD10 and has shifted some of the vertical wind shear to the west. Further, TD9’s circulation has helped to steer the dry, dusty and therefore inhibitive Saharan Air Layer a little further to the north of TD10. So in some ways TD9’s demise has helped make the environment somewhat more conducive for development for TD10. The NHC expects TD10 to become a tropical storm in the next day or so as it tracks west-northwestward with gradual strengthening through the next five days.

The 8.3 Magnitude Earthquake struck around 2300UTC 16th September. Just over an hour later we see the water level fluctuate abnormally and dramatically between 8 feet below normal to 13 feet above normal at Coquimbo, Chile. Smaller waves continue to impact the area as of September 18th, likely resulting in dangerous currents and water level changes.

Meanwhile, in the Southeastern Pacific a “Great” earthquake struck just off the coast of Chile overnight on Wednesday and it generated a notable Tsunami. The tsunami peaked along the adjacent coast of Chile where tsunami waves combined with the incoming high tide (high tide is about 2ft above mean sea level) reached as high as 13 feet above mean sea level and inundated several coastal areas. Sizable tsunami waves were also measured in Hawaii where tsunami waves up to 4 feet above mean sea level were measured, and a small but measurable tsunami was also measured in places as far away as Alaska and Japan.

Water level data found at – Sea Level Station Monitoring Facility converted to feet from meters.