A mostly sunny weekend will be followed by a good chance of showers early next week in the North Country, according to the National Weather Service.

After the heat of the last few days, a welcome cooling trend is taking hold in the St. Lawrence Valley.

The NWS says cooler and wetter weather is on the way, as a large upper-level low pressure system moves toward the region and is expected to stall over northern New England.

High temperatures are expected to be in the upper 70s through Sunday, after which the highs will be in the 60s through next Wednesday.

There is a slight chance of showers and maybe thunderstorms Saturday and Sunday. The likelihood of rain climbs on Sunday night and Monday.

For the rest of the week, the forecast is for mostly cloudy skies and a 30 percent chance of showers.

The NWS forecast for the St. Lawrence Valley and northwest Adirondacks:

This Afternoon: Mostly sunny, with a high near 80. West wind around 10 mph.

Tonight: Partly cloudy, with a low around 55. West wind between 3 and 6 mph.

Saturday: A chance of showers, with thunderstorms also possible after 11am. Mostly sunny, with a high near 78. North wind between 5 and 7 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Saturday Night: Mostly clear, with a low around 50. West wind around 5 mph becoming calm.

Sunday: A slight chance of showers between noon and 2pm, then a chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 79. West wind between 5 and 9 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Sunday Night: A chance of showers and thunderstorms, then showers likely after 8pm. Mostly cloudy, with a low around 59. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Monday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 69. Chance of precipitation is 60%.

Monday Night: A chance of showers. Mostly cloudy, with a low around 51. Chance of precipitation is 40%.

Tuesday: A chance of showers. Mostly cloudy, with a high near 67. Chance of precipitation is 50%.

Tuesday Night: A chance of showers. Mostly cloudy, with a low around 50. Chance of precipitation is 30%.

Wednesday: A chance of showers. Mostly cloudy, with a high near 69. Chance of precipitation is 40%.

Wednesday Night: A chance of showers. Mostly cloudy, with a low around 54. Chance of precipitation is 30%.

Thursday: A chance of showers. Mostly cloudy, with a high near 73. Chance of precipitation is 30%.