Update, 3:50 p.m.
The Pittsburgh Department of Public Works says approximately 50 to 60 vehicles “will be deployed throughout the city to monitor conditions and treat streets overnight” with crews working 12-hour shifts starting at 10 p.m.
“Due to the hazardous conditions that result from freezing rain, city officials encourage all residents to stay indoors and off of the roads, if possible,” DPW said in a release. Read more here.
This weekend’s weather will have everything: Snow! Sleet! Freezing rain! Regular rain! Plus freezing temperatures.
Pittsburgh will be under a winter storm warning from 10 tonight until 1 p.m. Saturday, which means “significant amounts of snow, sleet and ice are expected or occurring. This will make travel very hazardous or impossible.”
Lee Hendricks, a meteorologist for the National Weather Service Pittsburgh, said snow is expected to start falling this evening — probably around 9 or 10 p.m. in the city — and after midnight, snow will transition to “freezing rain mixed with snow and sleet.”
“We can get an accumulation by tomorrow morning of snow and sleet of around an inch,” he said.
It will be around 20 degrees overnight, with a possible ice accumulation of a 10th to a quarter of an inch.
“Which doesn’t sound like a lot until you try to drive on it,” Hendricks said, “especially on Mt. Washington.”
Freezing rain will linger into Saturday morning, with temperatures rising rapidly.
“But the ground is still going to be frozen,” Hendricks said. “You’ll have the rain hitting the frozen surface and freezing on contact.”
Between 11 a.m. and 1 p.m. Saturday — “it’s hard to pinpoint it” — the precipitation will “change over to all rain,” Hendricks said. In the late afternoon, the temperature is expected to be in the low 50s. By then, road surfaces should no longer be frozen.
If you have specific questions for NWS Pittsburgh, you can tweet at them.