MEXICO CITY -- Hurricane Bud made a brief run as a powerful Category 4 storm off Mexico's Pacific coast, but quickly weakened into a tropical storm by Wednesday morning, easing -- but not completely ending -- the threat to resorts in its path at the southern tip of the Baja California peninsula.

The U.S. National Hurricane Center said Bud's maximum sustained winds had lessened to 50 mph (85 kph) by midafternoon, down from 130 mph (210 kph) the day before. It was projected to weaken further, but was still expected to be at tropical storm force when it reached the peninsula late Thursday.

A tropical storm warning was issued for a stretch of coast from Santa Fe to La Paz that includes the twin resort cities of Los Cabos.

Bud was centred about 215 miles (305 kilometres) south-southeast of Cabo San Lucas at the peninsula's southern tip and was moving north-northwest at about 6 mph (9 kph).

The forecast path would carry it near Cabo San Lucas and San Jose del Cabo, which are popular destinations for international and domestic travellers with millions of visitors each year.

The centre said the hurricane could cause dangerous surf along Mexico's nearby coasts for the next several days. Heavy rainfall also was predicted for southwestern and western Mexico as well as the southern Baja peninsula.

The Los Cabos Tourism Board said in a statement that it did not anticipate significant damage from the storm and that airline and transportation operations were operating normally, though aviation delays were expected.

It urged people to "exercise caution and vigilance" and "refrain from participating in any sort of recreational water activity until further word from the Mexican National Civil Protection System."