Former Tropical Storm Erin strengthened to a hurricane east of the Northern Leeward Islands on Friday.  At 11:00 a.m. EDT on Friday the center of Hurricane Erin was located at latitude 18.2°N and longitude 56.1°W which put the center about 460 miles (740 km) east of the Northern Leeward Islands.  Erin was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 996 mb.

Tropical Storm Watches are in effect for Anguilla, Barbuda, St. Martin, St. Barthelemy, Saba, St. Eustatius, and Sint Maarten.

Former Tropical Storm Erin strengthened to a hurricane east of the Northern Leeward Islands on Friday.  The inner end of a rainband wrapped around the center of Erin’s circulation.  A small eye with a diameter of 12 miles (19 km) formed at the center of Hurricane Erin.  Bands of showers and thunderstorms were revolving around the center of Erin’s circulation.  Storms near the center generated upper level divergence that was pumping mass away from the hurricane.

The strongest winds were occurring in the northeastern part of Hurricane Erin.  Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Erin’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Hurricane Erin.

Hurricane Erin will move through an environment favorable for intensification during the next 24 hours.  Erin will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level ridge over the eastern Atlantic Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Erin’s circulation. The winds in the lower levels of the atmosphere will also blow from the east, but winds will be stronger in the upper troposphere.  So, there will be some vertical wind shear.  The vertical wind shear will slightly inhibit intensification, but the shear will not be enough to prevent intensification. Hurricane Erin will intensity during the next 24 hours.  Erin is likely to strengthen to a major hurricane during the weekend.

Hurricane Erin will move around the southern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Erin toward the west-northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Storm Erin will pass north of the Northern Leeward Islands on Saturday.

Bands in the southern side of Hurricane Erin are likely to bring gusty winds and locally heavy rain to the Northern Leeward Islands.  Heavy rain could cause flash floods in some locations.  Bands feeding into the southern side of Hurricane Erin could also drop heavy rain on Puerto Rico.

A Flood Watch is in effect for Puerto Rico.