Frank (2016)

A broad tropical wave that moved off Africa on 10 July developed into Tropical Depression Seven about 250 nautical miles south of Manzanillo, Mexico at 0600 UTC 21 July. The system strengthened into Tropical Storm Frank the same day and moved generally west-northwest, passing very near Socorro Island on 23 July. Steering currents later weakened and Frank meandered for a few days, then accelerated and organized again on 26–27 July. Frank weakened rapidly over cooler waters and became a remnant low by 1200 UTC 28 July, with the remnant circulation dissipating by the end of July.

Frank passed over or just north of Socorro Island on 23 July, producing sustained tropical-storm-force winds there; no other landfalls were recorded on mainland Mexico. There were no watches or warnings issued for the storm.

The storm’s peak intensity occurred at 0000 UTC 27 July, with maximum sustained winds of 75 kt (about 85 mph) and a minimum central pressure of 979 mb. At peak strength Frank was a Category 1 hurricane on the Saffir–Simpson scale.

Socorro Island recorded sustained west winds of 39 kt (45 mph) with gusts to 55 kt (63 mph) around 2315 UTC 23 July; tropical-storm-force gusts persisted on the island for about 12 hours. The report did not list specific storm surge measurements or inland rainfall totals for cities or counties, and no significant surge or heavy-rainfall reports for mainland locations were noted.

There were no reports of damage or casualties—no direct or indirect deaths were reported. The Mexican Navy weather station on Socorro Island provided the primary in situ observations of tropical-storm-force winds associated with Frank.

Noteworthy items include that Frank was the fifth hurricane to form in the eastern North Pacific during July 2016, setting a new record for that month, and that the NHC official track forecasts for Frank performed better than the recent 5-year mean. The cyclone’s short-range formation was not well forecast, and intensity forecasts tended to strengthen Frank too early and weaken it too soon compared to the observed best track.