Forecasters have re-upgraded tropical storm Sandy to a hurricane, just hours after raising hopes that the winds were losing strength.
The National Hurricane Center said Saturday morning that a Hurricane Hunter aircraft had recorded sustained winds of 75 mph – enough to reclassify the storm to Category 1 hurricane status.
The weather system so far has left 41 people dead in a trail of destruction across the Caribbean. Experts have warned that the storm system could inflict "widespread impacts" along the east coast of the United States when it could make landfall as early as Monday.
New York, Virginia and Maryland declared states of emergency on Friday as experts feared Hurricane Sandy could become a storm of "historic" proportions.
Sandy could strike the US coastline anywhere between Virginia and Massachusetts, forecasters said.
Meteorologists warned that weather conditions could be complicated as Sandy is expected to meet two separate weather systems somewhere over the north-east US, resulting in high winds, heavy rain, extreme tides and perhaps even snow.
"It's looking like a very serious storm that could be historic," said Jeff Masters, meteorology director of the forecasting service Weather Underground. He compared the convergence of weather systems to the so-called "perfect storm" that struck off the coast of New England in 1991, although that storm hit a less populated area.
The National Oceanic and Atmospheric Administration said on Friday that wherever the storm comes ashore, there will be 10 inches or more of rain and extreme storm surges. Up to 2 feet of snow should fall on West Virginia, with lighter snow in parts of Ohio and Pennsylvania.
"It's going to be a long-lasting event, two to three days of impact for a lot of people," said James Franklin, forecast chief for the National Hurricane Center.