A very warm airmass will develop across the St. Lawrence Valley today and continue through mid week, according to the National Weather Service (NWS).

Temperatures will soar into the mid 80s to lower 90s for both Tuesday and Wednesday, with just a slight chance of a shower or thunderstorm, NWS says.

Today will see sunny skies with highs around 90 and an overnight low around 67, forecasters said. Highs on Wednesday will be around 89.

The chances for showers and thunderstorms increase late Thursday into Friday, as a surface cold front impacts the region, the service says.

Some localized heavy downpours are possible with the stronger convection on Friday, NWS says. Much cooler and drier weather is anticipated for the weekend as strong high pressure building into the area.

The forecast through Monday is as follows:

Wednesday

Mostly sunny, with a high near 89. Southwest wind 7 to 9 mph.

Wednesday Night

Mostly cloudy, with a low around 68. Light southwest wind increasing to 5 to 9 mph in the evening.

Thursday

A 30 percent chance of showers after 5pm. Partly sunny, with a high near 84. Southwest wind around 11 mph.

Thursday Night

A 40 percent chance of showers after 7pm. Mostly cloudy, with a low around 68. South wind 8 to 10 mph. New precipitation amounts of less than a tenth of an inch possible.

Friday

Showers likely. Mostly cloudy, with a high near 83. Southwest wind 10 to 15 mph. Chance of precipitation is 60%.

Friday Night

A 40 percent chance of showers. Mostly cloudy, with a low around 58. Southwest wind 7 to 10 mph.

Saturday

Partly sunny, with a high near 70. West wind 8 to 13 mph.

Saturday Night

Partly cloudy, with a low around 43. Northwest wind around 7 mph.

Sunday

Mostly sunny, with a high near 61. Northwest wind 8 to 11 mph.

Sunday Night

Partly cloudy, with a low around 41. West wind 5 to 7 mph.

Monday

Mostly sunny, with a high near 63. Northwest wind 6 to 11 mph.