Miami , Florida ( CNN ) -- Forecast to gain `` major '' Category 3 status , outer rainbands association with a strengthening Hurricane Earl were affecting the islands of Antigua and Barbuda on Sunday , with conditions forecast to deteriorate , the National Hurricane Center said . Earl became a Category 1 hurricane on Sunday . As of 8 p.m . ET , its center was about 100 miles ( 160 kilometers ) east of Barbuda and about 185 miles ( 300 kilometers ) east of St. Martin . Its maximum sustained winds had increased slightly to 85 mph ( 140 kph ) and higher gusts , and the storm was heading west-northwest at near 14 mph ( 22 kph ) . The center of Earl is forecast to pass near or over the northern Leeward Islands Sunday night and Monday , the center said . A hurricane warning was in effect for Antigua , Barbuda , Montserrat , St. Kitts , Nevis , Anguilla , St. Martin , St. Barthelemy , Saba and St. Eustatius . As of 5 p.m. , the government of Antigua and Barbuda also had added the British Virgin Islands to the warning , forecasters said . A hurricane watch and a tropical storm warning was in effect for the U.S. Virgin Islands and Puerto Rico , including the islands of Culebra and Vieques . Tropical storm-force conditions were forecast in the warning area Sunday afternoon and evening , with hurricane conditions expected early Monday , forecasters said . Tropical storm conditions were expected to spread across the Virgin Islands and Puerto Rico on Monday , with hurricane conditions possible on Monday night . `` Strengthening is expected during the next 48 hours , and Earl is forecast to become a major hurricane by Tuesday , '' forecasters said . Earl was forecast to turn west-northwest and slow down over the next day . Tracking maps show it moving northward away from the Caribbean and possibly affecting the U.S. East Coast by Friday . Easterners should pay attention to Earl , as it could affect areas anywhere from the Carolinas to Cape Cod , Massachusetts , over Labor Day weekend , said CNN meteorologist Jacqui Jeras . It is too soon to tell whether the storm could make landfall , she said . However , outer bands of the storm are likely to hit North Carolina beginning Thursday , kicking up large swells and possibly generating rip currents through Labor Day weekend , Jeras said . Earl is expected to dump between 3 and 5 inches of rain over the northern Leeward Islands , with isolated amounts of 8 inches possible in some areas . Puerto Rico is expected to receive between 4 and 6 inches of rain , with isolated amounts of 12 inches possible over higher elevations . In addition , Earl is expected to produce a 2-to-4-foot storm surge within the hurricane warning area , and 1-to-3-foot storm surge in coastal areas , accompanied by high surf . Meanwhile , Hurricane Danielle remained away from land , and was gradually weakening as it moved northeastward , the hurricane center said . The center of the storm was about 605 miles ( 975 kilometers ) south of Cape Race , Newfoundland . Once a Category 4 storm , Danielle had weakened Sunday to a Category 1 hurricane with winds of near 80 mph ( 130 kph ) . It was expected to continue to weaken , and was moving north-northeast at near 29 mph ( 46 kph ) . Large waves and dangerous surf conditions should diminish near Bermuda on Sunday , the hurricane center said , and `` swells from Danielle are expected to gradually subside during the next day or two along portions of the United States East Coast . '' A number of people were rescued along the East Coast because of those swells and riptide currents . Nearly 250 were rescued Saturday in the waters off Ocean City , Maryland , authorities said . In addition , an area eastward from Earl could develop into a tropical depression and then potentially into Tropical Storm Fiona , Jeras said .
Too soon to tell whether Earl could dampen U.S. Independence Day . Outer rainbands were reaching Antigua and Barbados . Earl reaches Category 1 intensity . Hurricane winds are the strongest on Leeward Islands .