Tag Archives: Hurricane Hilary

Hurricanes Hilary and Irwin Churn Over Eastern Pacific

Hurricanes Hilary and Irwin continued to churn over the Eastern North Pacific Ocean on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Hilary was located at latitude 16.0°N and longitude 109.8°W which put it about 475 miles (765 km) south of the southern tip of Baja California.  Hilary was moving toward the west-northwest at 12 m.p.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 973 mb.

At 11:00 p.m. EDT on Tuesday the center of Hurricane Irwin was located at latitude 16.1°N and longitude 120.9°W which put it about 855 miles (1375 km) west-southwest of the southern tip of Baja California.  Irwin was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 980 mb.

Hilary is the larger and stronger of the two hurricanes.  Hurricane Hilary has a small circular eye surrounded by a ring of strong thunderstorms.  A rainband spirals around the western and southern sides of the core of the circulation.  Thunderstorms in the core are generating strong upper level divergence which is pumping out mass in all directions.  Winds to tropical storm force extend out about 90 miles (145 km) from the center.

Hurricane Irwin has a smaller circulation.  Irwin has a small eye.  Most of the thunderstorms are occurring in the northwestern quadrant of the circulation.  Winds to tropical storm force extend out only about 70 miles (110 km) from the center of circulation.

Hurricane Hilary is moving through a more favorable environment.  Hilary is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear near Hilary.  Hurricane Irwin is moving over water where the Sea Surface Temperature is near 28°C.  An upper level low northwest of Irwin appears to be producing westerly winds which are undercutting the upper level divergence generated by thunderstorms near the core of the hurricane.  Some drier air also seems to wrapping around the eastern side of the circulation.

Hurricane Hilary is moving faster than Hurricane Irwin and Hilary is getting closer to Irwin.  The two hurricanes are expected to interact later this week.  Since Hilary is bigger and stronger than Irwin, Hilary is forecast to become the dominant circulation.  Hurricane Hilary is expected to continue to move in west-northwesterly direction.  When Hilary gets closer to Hurricane Irwin, Irwin is forecast to begin to revolve around Hilary in an interaction called the Fujiwhara effect.  On their anticipated tracks Hurricanes Hilary and Irwin are expected to remain south of the southern tip of Baja California.