PITTSBURGH (KDKA) – Slow down, plan extra time for your commute and leave space in between your car and the vehicle in front of you.

That’s the advice the Allegheny County Department of Public Works is giving drivers for their Friday morning commutes. The area is expected to see anywhere from 3 to 5 inches of snow tomorrow, with heavy snow expected during rush hour.

Public Works says 26 salt trucks with plows will head out at 2 a.m. early Friday morning to start prepping roads.

Sometime during the morning commute, KDKA’s Ron Smiley says the rain we’re seeing today will change to snow. Since rain is coming in first, crews will not be able to pre-treat the roads in anticipation of the snow.

It’s this bad timing that’s causing the concern.

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This is also about the time that temperatures also will hit the 32-degree range, meaning that we will have snow accumulating shortly after it begins to fall.

However, while Allegheny County Public Works says they’re preparing for 3 to 5 inches, Ron Smiley is predicting the accumulation will be around 2 inches in the Pittsburgh area.

He says locations farther north will have a higher chance of seeing snow totals nearing 4 inches as you cross over Interstate 80. Some isolated spots in the Laurel Mountains will likely see upwards of 6 inches of snow.

Each school district has its own protocol for canceling or delaying classes.

WATCH: KDKA’s Shelby Cassesse Reports Live From The North Shore

But with snowfall expected to start as teachers and students prepare to head out the door, some districts may have to make a last-minute decision.

School districts said they try to make decisions as soon as possible, but sometimes the unpredictable weather makes that difficult.

One of those districts waiting to make a decision is Chartiers Valley School District, which released a statement, saying:

“Any interruption to instruction is unfortunate, but when snow is in the forecast, safety of our students and staff is the first priority. Dr. Vanatta works closely with local law enforcement and the District’s transportation department to discern whether or not a delay or closing is necessary. While we make every effort to notify our families of delays/closings with as much advance notice as possible, Pittsburgh weather can be unpredictable and sudden, which can result in last-minute decisions in the interest of safety.

“Chartiers Valley utilizes a mass messaging system, the District website, social media, and news media to alert families when a weather delay or cancellation is necessary.”

KDKA Morning News will start early at 4 a.m. on Friday to track this snow and the road conditions.

You can also stay up to date with the KDKA app, which you can download here.