Hurricane Simon strengthened into a high-end Category 4 storm Saturday night, packing 155 mph winds as its eyewall moved within about 65 miles of Manzanillo on Mexico's Pacific coast — and forecasters warn the worst is about to come ashore.
The National Hurricane Center said in its 9 p.m. Central advisory Saturday that Simon's maximum sustained winds had risen to 155 mph with higher gusts, and its estimated central pressure had fallen to 928 millibars. The eyewall was approaching the coast, and the center was expected to be near or just inland over west-central Mexico on Sunday.
The rapid strengthening is what makes Simon so dangerous. The storm had maximum sustained winds of just 105 mph Friday afternoon — by late Saturday it had gained about 50 mph, sharply cutting the time coastal communities had to prepare. Air Force Reserve reconnaissance planes measured a central pressure of 932 millibars earlier Saturday as the storm crawled north at only about 5 mph.
A hurricane warning is in effect from Punta San Telmo to El Roblito, including the Islas Marias archipelago, with a tropical storm watch farther south toward Lazaro Cardenas. Hurricane-force winds extend up to 25 miles from Simon's center, with tropical-storm-force winds reaching 90 miles out.
The rainfall threat is severe. The Hurricane Center says Simon could dump 10 to 20 inches of rain across parts of southwestern Mexico through Sunday, with isolated totals up to 30 inches in Michoacan, Colima and Jalisco — enough to trigger life-threatening flooding and mudslides, especially in steep terrain. A dangerous storm surge with large, destructive waves is expected near and east of wherever the center crosses the coast.
In Manzanillo, Mexico's largest Pacific port, the mood Saturday afternoon was calm but tense. Reuters reported little panic buying at supermarkets, though some stores had begun boarding up windows, businesses were closing, and streets were relatively empty. Rain had been falling intermittently since late Friday, and rising seas were pushing waves almost to the entrances of beachfront hotels. Civil protection workers closed beaches, erected barriers and raised red and black warning flags. Marines, soldiers, National Guard officers and emergency personnel patrolled flood- and landslide-prone areas, while authorities began precautionary evacuations in parts of Cihuatlan in neighboring Jalisco. Rivers in some areas were already running high.
Jalisco suspended classes Friday and Monday in 22 coastal municipalities and began moving people from vulnerable areas. In Puerto Vallarta, businesses boarded windows and secured properties as officials told residents and visitors to stay indoors.
The Hurricane Center expects Simon to weaken after moving inland over Mexico's mountainous terrain — but the rainfall could stay dangerous well beyond the coastal landfall zone, and even a small shift in track could decide which communities take the strongest winds.