Rain is coming to the St. Lawrence Valley later today and tonight, and it could be heavy at times.

Clouds have overspread the North Country in advance of a developing surface low pressure system expected to begin moving into the region by late afternoon.

As the low develops, much-needed rain is expected to develop across the North Country, especially late this afternoon and into this evening.

Rain will become moderate to briefly heavy tonight as low pressure moves eastward.

Rainfall amounts will range from around a half inch along the St. Lawrence River to 1 to 2 inches across eastern New York.

A few embedded thunderstorms are also possible this evening through tonight.

The low pressure system moves eastward Wednesday morning, but humid conditions will prevail Wednesday and Thursday with high temperatures into the 80s.

A weak cold front brings somewhat cooler and drier conditions for Friday.

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

This Afternoon: A chance of rain and thunderstorms, then rain likely and possibly a thunderstorm after 3pm. Cloudy, with a high near 78. Light southeast wind. Chance of precipitation is 60%. New rainfall amounts between a quarter and half of an inch possible.

Tonight: Rain and possibly a thunderstorm. Low around 66. Light northeast wind. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.

Wednesday: A slight chance of showers. Cloudy, then gradually becoming mostly sunny, with a high near 80. Northeast wind 5 to 7 mph. Chance of precipitation is 20%.

Wednesday Night: Patchy dense fog after midnight. Otherwise, partly cloudy, with a low around 61. Calm wind.

Thursday: A chance of showers after 2pm. Mostly sunny, with a high near 78. Calm wind becoming southwest 5 to 7 mph in the afternoon. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Thursday Night: A chance of showers. Partly cloudy, with a low around 57. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch possible.

Friday: A slight chance of showers. Mostly sunny, with a high near 74.

Friday Night: Mostly cloudy, with a low around 53.

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

Saturday Night: A chance of showers. Mostly cloudy, with a low around 51. Chance of precipitation is 30%.

Sunday: A chance of showers. Partly sunny, with a high near 71. Chance of precipitation is 30%.

Sunday Night: A slight chance of showers. Partly cloudy, with a low around 50.

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