Hurricane Priscilla Starts to Weaken

Hurricane Priscilla started to weaken on Tuesday evening.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Priscilla was located at latitude 20.6°N and longitude 111.5°W which put the center about 190 miles (305 km) south-southwest of the southern tip of Baja California.  Priscilla was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 962 mb.

A Tropical Storm Watch was in effect for the portion of the coast from Cabo San Lucas to Cabo San Lazaro, Mexico.

Hurricane Priscilla started to weaken on Tuesday evening after Priscilla had strengthened to Category 2 on the Saffir-Simpson Scale earlier in the day.  Hurricane Priscilla appeared to have mixed cooler water to the surface of the Eastern North Pacific Ocean.  A large eye with a diameter of 50 miles (80 km) was still present at the center of Priscilla’s circulation.  However, the ring of thunderstorms surrounding the eye was broken in several places.  Also, many of the thunderstorms in bands in the eastern side of Hurricane Priscilla had weakened.  The bands in the eastern part of Priscilla’s circulation consisted primarily of showers and lower clouds.  Thunderstorms were still occurring in bands in the western half of Hurricane Priscilla.

The circulation around Hurricane Priscilla was still large.  Winds to hurricane force extended out 45 miles (75 km) from the center of Priscilla’s circulation.  Winds to tropical storm force extended out 195 miles (315 km) from the center of Hurricane Priscilla.

The Hurricane Intensity Index (HII) for Hurricane Priscilla was 17.8.  The Hurricane Size Index (HSI) was 17.1 and the Hurricane Wind Intensity Size Index (HWISI) was 34.9.

Hurricane Priscilla will move through an environment that will become more unfavorable for intensification during the next 24 hours.  An upper level trough near the west coast of the U.S. will start to produce southwesterly winds that will blow toward the top of Priscilla’s circulation.  Those winds will cause the vertical wind shear to begin to increase.  In addition, the cooler water mixed to the surface of the ocean by Priscilla’s winds will limit the energy transfer from the ocean to the atmosphere.  The effects of cooler water and increasing vertical wind shear will cause Hurricane Priscilla to weaken during the next 24 hours.

Hurricane Priscilla will move around the western end of a high pressure system over Mexico.  The high pressure system will steer Priscilla toward the north-northwest during the next 24 hours.  On its anticipated track, Hurricane Priscilla will move parallel to the coast of southwestern Baja California on Wednesday.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Octave weakened far to the southwest of Baja California.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Octave was located at latitude 15.2°N and longitude 118.0.°W which put the center about 750 miles (1205 km) southwest of the southern tip of Baja California.  Octave was moving toward the east at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1000 mb.