Rosa (2018)

A tropical depression formed about 350 nautical miles south-southwest of Manzanillo, Mexico, at 0600 UTC on 25 September 2018. It strengthened to Tropical Storm Rosa later that day and moved generally west-northwest then west under a subtropical ridge. Rosa underwent rapid intensification as its inner core consolidated and became a hurricane on 26 September. The hurricane reached peak strength on 28 September and then weakened over the next few days as it turned northwest and later northeast toward the Baja California peninsula. The circulation dissipated after interacting with the peninsula’s high terrain on 2 October.

Rosa did not make a strong hurricane landfall. The best-track indicates the system made landfall about 60 nautical miles southeast of Punta San Antonio on the west-central Baja California peninsula just before 1200 UTC on 2 October as a tropical depression (30 kt). The circulation was no longer a hurricane or tropical storm at landfall.

The storm’s maximum intensity occurred at 0600 UTC 28 September with peak sustained winds of 130 knots (150 mph) and a minimum central pressure of 936 millibars, corresponding to a Category 4 hurricane on the Saffir–Simpson scale.

Storm surge reports were minimal in the official record. Rainfall was more notable on northern Baja California: the highest 24-hour total in the report was 6.50 inches (166 mm) at the town of Percebú. Mexican naval stations recorded wind gusts of about 40 kt on Isla Cedros (around 2100 UTC 1 October) and 46 kt on Isla Guadalupe (around 1500 UTC 1 October).

There were no reports of damage or casualties associated with Rosa. The hurricane caused only minimal impacts to land areas because it weakened greatly before reaching the Baja California peninsula. Noteworthy points: Rosa underwent rapid intensification to a major Category 4 hurricane over open water, and NHC track forecasts for Rosa were generally more accurate than recent five-year means while intensity forecasts were comparable or better at longer lead times.