Nora formed early on September 16, 1997, while located 290 miles (460 km) southwest of the Mexican port of Acapulco, Guerrero, from the same tropical wave that had earlier created Hurricane Erika.
Due to favorable conditions associated with El Niño, the tropical disturbance quickly achieved deep convection and became well-organized.
By 6 a.m. UTC, the U.S. National Hurricane Center had designated the disturbance as Tropical Depression Sixteen-E. Half a day later, it had gained enough strength to be named Tropical Storm Nora.

A high pressure area over northern Mexico forced the storm to move west-northwest for the first few days.
During that time, Nora kept intensifying, becoming a Category 1 hurricane on the Saffir–Simpson hurricane scale by noon UTC on September 18.
Nora slowed and became stationary for two days from September 18.
The eye vanished, and convection began to decrease.
This was presumed to have happened because of a drop in sea-surface temperatures.
The cool waters temporarily weakened Nora's winds to 75 mph (120 km/h) down from a maximum of 105 mph (165 km/h).
After leaving the area of cool waters, the storm began moving nearly parallel to Mexico's western coast.
There was a period of rapid intensification and the eye reappeared.
Cloud tops cooled and at midday UTC on September 21, Nora reached its peak intensity of 950 mbar (28 inHg) and 135 mph (210 km/h) winds, a Category 4 hurricane.
The peak was brief as the cyclone encountered cool waters in the wake of Hurricane Linda, weakening the storm's winds to 80 mph (130 km/h) by September 23 and broke its eyewall.

Nora crossed an area of abnormally warm water near the west coast of the Baja California Peninsula.
It restrengthened slightly before making its first landfall near Bahía Tortugas, Baja California Sur, on September 25.
When Nora was inland, the area of the storm located in the Gulf of California began to reintensify.
Hurricane Nora then made a second landfall about 60 miles (95 km) south-southeast of San Fernando, Baja California.

At landfall, a trough was accelerating Nora northwards, causing it to reach a forward speed of 30 mph (50 km/h).
Late on September 25 (UTC), still a tropical storm, it entered the continental United States at the California-Arizona state line.
Nora began to weaken rapidly, and was downgraded to a tropical depression three hours later, while located 1 mile north of  Vidal Junction, California.
Nora reached Arizona while still tropical, becoming the third known system to do so.
Nora degenerated over land, and the low-level center moved towards the north-northeast.
A remnant circulation aloft persisted, however, and was likely responsible for a period of near hurricane-force winds observed at the NWS Cedar City, Utah Doppler weather radar.
The remnants of Nora gradually became more diffuse over the following two days while moving generally northeastward, through portions of Utah, Colorado, Idaho, and Wyoming, before dissipating on September 28.
Nora formed early on September 16, 1997, while located 290 miles (460 km) southwest of the Mexican port of Acapulco, Guerrero, from the same tropical wave that had earlier created Hurricane Erika. Due to favorable conditions associated with El Niño, the tropical disturbance quickly achieved deep convection and became well-organized. By 6 a.m. UTC, the U.S. National Hurricane Center had designated the disturbance as Tropical Depression Sixteen-E. Half a day later, it had gained enough strength to be named Tropical Storm Nora.
A high pressure area over northern Mexico forced the storm to move west-northwest for the first few days. During that time, Nora kept intensifying, becoming a Category 1 hurricane on the Saffir–Simpson hurricane scale by noon UTC on September 18. Nora slowed and became stationary for two days from September 18. The eye vanished, and convection began to decrease. This was presumed to have happened because of a drop in sea-surface temperatures. The cool waters temporarily weakened Nora's winds to 75 mph (120 km/h) down from a maximum of 105 mph (165 km/h). After leaving the area of cool waters, the storm began moving nearly parallel to Mexico's western coast. There was a period of rapid intensification and the eye reappeared. Cloud tops cooled and at midday UTC on September 21, Nora reached its peak intensity of 950 mbar (28 inHg) and 135 mph (210 km/h) winds, a Category 4 hurricane. The peak was brief as the cyclone encountered cool waters in the wake of Hurricane Linda, weakening the storm's winds to 80 mph (130 km/h) by September 23 and broke its eyewall.
Nora crossed an area of abnormally warm water near the west coast of the Baja California Peninsula. It restrengthened slightly before making its first landfall near Bahía Tortugas, Baja California Sur, on September 25. When Nora was inland, the area of the storm located in the Gulf of California began to reintensify. Hurricane Nora then made a second landfall about 60 miles (95 km) south-southeast of San Fernando, Baja California.
At landfall, a trough was accelerating Nora northwards, causing it to reach a forward speed of 30 mph (50 km/h). Late on September 25 (UTC), still a tropical storm, it entered the continental United States at the California-Arizona state line. Nora began to weaken rapidly, and was downgraded to a tropical depression three hours later, while located 1 mile north of  Vidal Junction, California. Nora reached Arizona while still tropical, becoming the third known system to do so. Nora degenerated over land, and the low-level center moved towards the north-northeast. A remnant circulation aloft persisted, however, and was likely responsible for a period of near hurricane-force winds observed at the NWS Cedar City, Utah Doppler weather radar. The remnants of Nora gradually became more diffuse over the following two days while moving generally northeastward, through portions of Utah, Colorado, Idaho, and Wyoming, before dissipating on September 28.
Hurricane Nora (1997)