A low pressure system approaching the St. Lawrence Valley will likely result in a few showers and isolated thunderstorms today, according to the National Weather Service (NWS).

Highs today will be around 85 with mostly sunny skies, NWS says. Overnight lows will be near 65.

Warm and humid conditions return Tuesday with the risk for a few afternoon thunderstorms, forecasters say.

More widespread storms and locally heavy rainfall are expected on Wednesday, the service says says.

The weather pattern remains unsettled for rest of the week with daily shower and thunderstorm chances, NWS says.

The extended forecast through Sunday is as follows:

Tuesday

A slight chance of showers between 1pm and 5pm, then a slight chance of showers and thunderstorms after 5pm. Mostly sunny, with a high near 89. Heat index values as high as 92. Southwest wind around 6 mph. Chance of precipitation is 20%.

Tuesday Night

A 30 percent chance of showers after 2am. Mostly cloudy, with a low around 70. South wind 3 to 6 mph. New precipitation amounts of less than a tenth of an inch possible.

Wednesday

Showers likely, with thunderstorms also possible after 11am. Mostly cloudy, with a high near 80. South wind 5 to 7 mph becoming west in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.

Wednesday Night

A 30 percent chance of showers before 2am. Mostly cloudy, with a low around 68. Southwest wind 3 to 6 mph. New precipitation amounts of less than a tenth of an inch possible.

Thursday

A 30 percent chance of showers after 2pm. Mostly sunny, with a high near 86. West wind 3 to 6 mph.

Thursday Night

A 30 percent chance of showers before 8pm. Partly cloudy, with a low around 69. Light and variable wind.

Friday

A 40 percent chance of showers after 2pm. Mostly sunny, with a high near 86. Light and variable wind becoming south around 5 mph in the afternoon.

Friday Night

A 30 percent chance of showers. Mostly cloudy, with a low around 69. South wind around 6 mph.

Saturday

A 50 percent chance of showers. Partly sunny, with a high near 83. South wind 6 to 8 mph becoming west in the afternoon.

Saturday Night

A 50 percent chance of showers. Mostly cloudy, with a low around 68. Northwest wind 5 to 9 mph becoming calm after midnight.

Sunday

A 40 percent chance of showers. Partly sunny, with a high near 82. Calm wind becoming west around 5 mph in the afternoon.