The core of Hurricane Simon stayed just to the west of the west coast of Mexico on Sunday. At 5:00 p.m. EDT on Sunday the center of Hurricane Simon was located at latitude 19.6°N and longitude 105.8°W which put the center about 55 miles (90 km) south of Cabo Corrientes, Mexico. Simon was moving toward the north-northwest at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 947 mb.
A Hurricane Warning is in effect for the portion of the coast from Punta San Telmo to El Roblito, Mexico. The Hurricane Warning includes Manzanillo and Puerto Vallarta.
A Hurricane Warning is in effect for Las Islas Marias.
A Hurricane Watch is in effect for the portion of the coast from El Roblito to Tempehuaya, Mexico.
Hurricane Simon was a Category 4 hurricane on the Saffir-Simpson Scale on Sunday afternoon.
A circular eye with a diameter of 10 miles (16 km) was at the center of Hurricane Simon. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Simon’s circulation. Storms near the core of Simon generated upper level divergence that pumped mass away from the hurricane. The removal of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere. So, the surface pressure increased on Sunday.
The circulation around Hurricane Simon was very small. Winds to hurricane force extended out 25 miles (40 km) from the center of Simon’s circulation. Winds to tropical storm force extended out 60 miles (95 km) from the center of Hurricane Simon.
The Hurricane Intensity Index (HII) for Hurricane Simon is 25.1. The Hurricane Size Index (HSI) is 8.2 and the Hurricane Wind Intensity Size Index (HWISI) is 33.3. Hurricane Simon is similar in intensity to Hurricane Harvey when Harvey hit Texas in 2017. Simon is smaller than Harvey was.
Hurricane Simon will move through an environment somewhat favorable for intensification during the next 24 hours. Simon will move over water where the Sea Surface Temperatures are near 30°C. It will move under the middle of an upper level ridge that is over Mexico and the Eastern North Pacific Ocean. The upper level ridge winds are weak near the middle of the ridge and there will be little vertical wind shear. However, Hurricane Simon is likely to pull some drier air that is over Mexico into its circulation because Simon will remain very close to Mexico. The drier air will inhibit the formation of new thunderstorms in the eastern and northern parts of Simon’s circulation. Hurricane Simon is likely to weaken on Monday because of the effects of the drier air.
Hurricane Simon will move around the western part of a high pressure system that is over Mexico. The high pressure system will steer Simon toward the north-northwest during the next 24 hours. On its anticipated track, the core of Hurricane Simon will remain just to the west of Mexico on Monday. The center of Simon’s circulation will pass just to the west of Cabo Corrientes on Sunday night. The core of Hurricane Simon will be near Las Islas Marias on Monday afternoon.
Bands in the eastern side of Hurricane Simon will continue to bring strong winds and locally heavy rain to the west coast of Mexico. The strongest winds and heaviest rains will occur in Colima, Jalisco and Nayarit. Heavy rain is likely to cause flash floods in some locations.
The core of Hurricane Simon will pass near Las Islas Marias on Monday afternoon. Simon will bring strong winds and heavy rain to those islands. Flash floods are likely to occur in some locations. Hurricane Simon could cause a storm surge of up to 13 feet (4 meters) along parts of coast of Las Islas Marias.