There's also a warning of heavy rainfall and possible thunderstorms.
Northampton and Lehigh counties are on a tornado watch until 11 this evening, according to the National Weather Service.There is a hazardous weather outlook for the Lehigh Valley as well as Warren and Hunterdon counties, the service alerts.
Forecasters warn of heavy rainfall, possible thunderstorms and wind gusts. There is also a chance of urban flooding and poor drainage.