Hurricane Irma moved toward the northern Leeward Islands on Sunday and Hurricane Watches were issued for a number of those islands.  At 11:00 p.m. EDT on Sunday the center of Hurricane Irma was located at latitude 17.2°N and longitude 51.0°W which put it about 710 miles (1145 km) east of the Leeward Islands.  Irma was moving toward the west-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 961 mb.

Hurricane Watches were in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, St. Maarten, St, Martin, and St. Barthelemy.

The circulation of Hurricane Irma is very well organized.  There is a nearly circular eye with a diameter of 30 miles (48 km) at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in the northeastern part of the ring.  Bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Thunderstorms around the core are generating strong upper level divergence which is pumping mass away in all directions from the hurricane.  Winds to hurricane force extend out about 35 miles (55 km) from the center.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Irma is 20.6.  The Hurricane Size Index (HSI) is 11.7 and the Hurricane Wind Intensity Size Index (HWISI) is 32.3.

Hurricane Irma will move through an environment favorable for intensification.  Irma will move over water where the Sea Surface Temperature is near 29°C and there is warmer water farther west.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Irma could intensify into a Category 4 hurricane on the Saffir-Simpson Scale.  There is a possibility that Irma could strengthen to Category 5 when it passes near the northern Leeward Islands and moves toward the Bahamas.  Hurricane Irma has already completed several eyewall replacement cycles and there could be more.  Each eyewall replacement cycle could result in fluctuations in the intensity of Hurricane Irma.

A strong subtropical high pressure system over the Atlantic Ocean is steering Hurricane Irma toward the west-southwest.  The high is forecast to weaken just a bit during the next several days and Hurricane Irma is expected to move more toward the west-northwest.  On its anticipated track Hurricane Irma will approach the northward Leeward Islands on Tuesday night.  It will be a strong, dangerous hurricane at that time.