Thunderstorms, high temps expected in St. Lawrence County today
Monday, June 18, 2018 - 10:01 am

High temperatures and a good chance of thunderstorms and heavy rain will dominate in the North Country today and tonight, according to forecasters from the National Weather Service.

Thunderstorms will develop ahead of a cold front mainly this afternoon into the evening. High temperatures will reach into the mid to upper 80s with heat index values into the 90s, forecasters say.

Any thunderstorms that form will be capable of producing very heavy downpours with potential for isolated flash flooding, gusty winds, and frequent lightning.

Breezy southwest winds could reach sustained speeds of 20 mph with possibly higher gusts around thunderstorms.

Showers and thunderstorms are expected to diminish later tonight but there is a continuing 80 percent chance of some showers then, forecasters predict. Lows tonight will be in the mid to upper 50s.

Much cooler and drier air will follow the frontal passage, leading to a pleasant day on Tuesday with sunny skies and highs in the mid 70s.

• Today: Showers and thunderstorms, mainly after 2pm. Some of the storms could produce gusty winds and heavy rain. High near 85. Heat index values as high as 91. Breezy, with a southwest wind 14 to 20 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.

• Tonight: Showers and thunderstorms before midnight, then a slight chance of showers between midnight and 2am. Some of the storms could produce gusty winds and heavy rain. Low around 58. Northwest wind 5 to 8 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

• Tuesday: Sunny, with a high near 74. Northwest wind 7 to 9 mph.

• Tuesday Night: Clear, with a low around 54. Calm wind.

• Wednesday: Sunny, with a high near 81. Southwest wind 6 to 9 mph.

• Wednesday Night: Partly cloudy, with a low around 52. North wind around 6 mph.

• Thursday: Sunny, with a high near 71. North wind 5 to 7 mph.

• Thursday Night: Mostly clear, with a low around 51. Light and variable wind.

• Friday: Sunny, with a high near 79. West wind 5 to 7 mph.

• Friday Night: Mostly clear, with a low around 57. South wind 3 to 5 mph.

• Saturday: A 40 percent chance of showers. Partly sunny, with a high near 77. Southwest wind around 7 mph.

• Saturday Night: A 40 percent chance of showers. Mostly cloudy, with a low around 61. South wind around 7 mph.

• Sunday: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 78. South wind around 9 mph.