The Weather Service has issued a flash-flood watch and hazardous weather warning for St. Lawrence County as thunderstorms are expected to bring as much as seven inches of rain by Sunday evening.

The flash-flood watch begins at 2 p.m. and will continue through Sunday evening.

Due to the recent drought condition precipitation runoff will be higher than normal leading to the potential for isolated flash flooding, the Weather Service says.

Moderate to high rises are expected on small streams and rivers with minor rises on mainstream rivers. The threat of flash flooding exists for any low-lying areas with poor drainage and urban locations that exceed 2-2.5 inches of rainfall over a three-hour window

According to the weather service, widespread persistent moderate to heavy rain will accompany showers and thunderstorms beginning this afternoon through Sunday evening. The highest chance for significant rainfall to occur this afternoon as a surface boundary will combine with high moisture to produce significant rainfall.

The weather services expect 1.5-2 inches of rain to towns on the St. Lawrence River this afternoon and this evening.

The front then sags south and will bring widespread showers and thunderstorms to the rest of the north country on Saturday leading to the potential for an additional 1.5-2.5 inches of rainfall for the rest of the area, the Weather Service says.