Frost advisory ends in Saskatoon, central Sask.

UPDATE: All advisories mentioned in this story have ended

A foggy phenomenon on the coldest morning Saskatoon has seen in four months with a risk of frost for the final day of summer tomorrow. Details below:

Frost Advisory

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A frost advisory has been issued for Saskatoon and portions of central Saskatchewan.

Environment Canada says frost may damage some crops in frost-prone areas.

Cool dry air and clearing skies will see temperatures fall to the freezing mark Tuesday night over central Saskatchewan and frost is expected into early Wednesday morning.

The agency recommends taking preventative measures to protect frost-sensitive plants and trees.

Saskatoon’s temperature is expected to dip a degree or 2 below freezing into early Wednesday morning with a wind chill in mid-minus single digits early in the day.

Watch below: How gardeners can protect plants against frost

Frost advisories are issued when temperatures are expected to the reach freezing mark during the growing season, leading to potential damage and destruction to plants and crops.

For the latest weather alerts download the Global News Skytracker weather app for iPhone, iPad or Android.

Morning Fog

A brilliant display of fog was seen in Saskatoon this morning over the river.

0:40 WATCH: Fog rolls down South Saskatchewan River into Saskatoon

WATCH ABOVE: Fog captured by Global’s Dakota Dunes Casino TowerCam on Tuesday morning

Fog is a low-lying cloud and forms when the air temperature and the dew point, the measure of moisture in the air, come close together.

This can occur either by the air temperature cooling to the dew point or if moisture is added to the air.

When either of those processes happens, the water vapour in the air condenses into small liquid water droplets suspended in the air, creating fog.

At this time of the year, the temperature of water bodies like the South Saskatchewan River will often be warmer than the air temperature.

This occurs because water has what’s called a higher specific heat capacity than air, meaning it will hold heat longer than the air and take longer to cool down than the air temperature in the fall (it will also take longer to warm up in the spring).

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Therefore, as cooler air moves in during the early morning as was the case today when Saskatoon dropped down to -0.6 for the first time in over 4 months, the river added moisture to the cooler air to bring the temperature close enough to the dew point to form fog.

Once the sun rose, temperatures warmed up quickly beyond the dew point and the fog started to clear.

Saskatoon Forecast

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Today

The morning began with fog patches, dipping back to -0.6 degrees – the coldest temperature seen in over 100 days, since May 14.

Mostly sunny skies quickly warmed us up into double digits by mid-morning and into the mid-teens by noon.

The mercury will continue to rise a few more degrees into the mid-to-upper teens under mostly to partly sunny skies.

Tonight

Mostly clear skies will stick around tonight as temperatures dip back below freezing by a degree or 2 with a risk of frost, so be sure to cover up your tomatoes and any other plants you’re concerned about that could be sensitive to frost.

Wednesday

It will feel like mid-minus single digits tomorrow morning with wind chill.

Clouds will make more a return tomorrow morning before gradually clear through the day, back to mostly sunny skies by late afternoon as high pressure once again takes hold.

Temperatures are expected to warm back up into the mid-teens once again for the final day of summer.

Thursday-Friday

The first day of fall on Thursday looks like it’ll start off near freezing once again with a risk of frost under sunny skies with some clouds building in late in the day and an expected afternoon high around 17 degrees.

An inverted trough brings in a chance of showers and cloudy skies on Friday with temperatures a bit cooler, back into the low teens for a daytime high.

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Weekend Outlook

A vertically stacked and precipitation packed low pressure system associated with that trough is likely to build into southeastern Saskatchewan on Saturday, bringing in a good chance of rain and cooler temperatures behind the system with an expected high in the low teens.

It looks like some upper ridging will build back in on Sunday, clearing skies out and warming temperatures back up into the mid-to-high teens.

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Saskatoon weather outlook is your one stop shop for all things weather for Saskatoon, central and northern Saskatchewan with a comprehensive look at your local forecast that you can only find here.