In addition to rain, strong storms starting today could potentially bring wind, hail and tornadoes, the National Weather Service reports.
Some weather experts say the Delaware River and smaller tributaries could flood as a result of continuing rain and rising water levels forecast this week for the Lehigh Valley and northwestern New Jersey.
A flood watch for this morning into Friday morning is in place for Lehigh, Northampton, Warren and Hunterdon counties, the National Weather Service reports. Tornadoes, strong damaging winds and large hail are also threats to the region, the service said.
It is expected to rain 1 to 3 inches today. While creeks, streams and some rivers are expected to spill over, the Delaware River should stay within its banks, said Kristin Kline, a National Weather Service meteorologist in Mount Holly, N.J.
"A few areas (of the Delaware River) will spill over with minor flooding, but we are not expecting really anything more at this point," Kline said.
The Delaware, which has a flood stage of 22 feet, was just below 10 feet Wednesday in Easton.
The weather service is predicting the river to crest at 14.5 feet by early Friday. Those projections often change once it starts raining. Prior to rain earlier this week, it had been about 4 feet, according to the U.S. Geological Survey.
AccuWeather predicts even higher levels. The Delaware is currently forecast to crest at 21.2 feet Friday afternoon, according to AccuWeather meteorologist Erik Pindrock. The Lehigh River at Bethlehem was at 4.3 feet and expected to reach 9.3 feet by tonight. Its flood stage is 12 feet, Pindrock said.
While the forecast calls for 1 to 3 inches, some areas are expected to accumulate more than 4 inches, he said. The projected rainfall, coupled with the accumulation of rain over the past week, is a concern for flooding, he said.
"That's certainly a lot of rain to be falling in a 24-hour period of time," he said. "We're very concerned with flooding, given some of the water levels at the rivers and tributaries already."
Nick Troiano, a meteorologist at WeatherWorks, said he expects minor flooding in the region.
"I don't think it will be widespread or major," he said.
Some organizations aren't taking the looming rainfall lightly.
The Clinton Police Department is urging residents and property owners in low-lying or poor-drainage areas to immediately take steps to prepare their properties to reduce the impact of potential flooding.
Kathleen Sandt, spokeswoman for the National Park Service, said park Superintendent John J. Donahue is ordering all individuals to wear a proper fitting, United States Coast Guard-approved personal flotation device while on board any vessel on the waters of the Delaware River within Delaware Water Gap National Recreation Area effective immediately until the river level recedes below 8 feet.
Sandt said she is expecting a "busy weekend in the park with some great weather over the weekend and many Father's Day and graduation celebrations taking place," but those events may be canceled due to the impending storm.
"Unfortunately the weather leading into the weekend will bring significant rainfall which will cause the Delaware river to rise considerably over the next few days," she said.
"When river levels reach 15 feet the river corridor and all access points in the park will be closed," Sandt said.