Norma (2017)

A tropical depression formed about 390 nautical miles south of the southern tip of the Baja California peninsula at 0600 UTC on 14 September 2017 and became Tropical Storm Norma six hours later. Norma moved northward, strengthened steadily, and reached hurricane strength around 0000 UTC 16 September about 235–240 n mi south of southern Baja. Steering currents then collapsed and Norma meandered on 16 September, weakened back to a tropical storm that same day, then resumed a north to west-northwest track through 18 September before weakening over cooler waters and becoming a remnant low by 0000 UTC 20 September. The remnant low dissipated shortly after 0600 UTC 22 September.

Norma did not make any landfall on the Baja California peninsula or mainland Mexico. Tropical storm watches and warnings were issued for portions of the coast from Los Barriles to Cabo San Lázaro during 16–18 September, but the storm weakened and turned away from shore, so no landfall occurred.

Norma’s peak intensity was estimated at 65 knots (75 mph) with a minimum central pressure of 985 mb around 0000–0600 UTC 16 September, making it a Category 1 hurricane at its maximum. Confidence in the exact peak intensity was assessed as low because different observation methods showed a wide spread of estimates.

There were no reports of storm surge or measured tropical-storm-force winds at land stations, and the report lists no specific storm-surge heights for coastal locations. Likewise, there were no rainfall totals reported for cities or counties in the NHC report associated with Norma; impacts from wind, surge, or rainfall in Mexico were not significant.

No deaths or damage were reported in association with Norma. Forecasts captured the storm’s formation well, but many track models and some official forecasts had a northeastward bias that incorrectly took Norma inland across Baja California; the European model and the Hurricane Weather Research and Forecasting model performed relatively better for this storm.