The advancing winter storm expected to sock southwest Ohio and the Miami Valley could make the Wednesday morning commute a tough one as there could be a few inches of snow in spots south of U.S. 36 and ice in the southeast portion of the region, Storm Center 7 Chief Meteorologist Jamie Simpson said Tuesday night.

Winds were already increasing Christmas Night, he said, “so some blowing and drifting may make for a tough go of it on the roads around sunrise, then the really heavy stuff will kick in late morning.  (Live Doppler 7 Radar)

“Midday still looks to be the worst of it when road crews will not be able to keep up with the snowfall rates and wind.”

Simpson said if the heavier precipitation arrives — it is expected in the time frame of 3 a.m. to 5 a.m. — and it is still freezing rain, the region could be dealing with some significant ice accumulations and power failures in far southeast Warren, Clinton and Greene counties.

The storm, the second of winter 2012-13, “will almost certainly be the greatest impact from any storm all winter,” he said.  (Sign up for weather alerts)

The National Weather Service in Wilmington on Tuesday afternoon expanded a blizzard warning until 1 a.m. Thursday for the following counties in Ohio: Auglaize, Butler, Champaign, Clark, Darke, Hardin, Logan, Mercer, Miami, Montgomery, Preble, Shelby, Union; and for Fayette, Franklin, Union and Wayne counties in Indiana.

The winter storm warning issued earlier by the weather service includes only Greene, Warren and Clinton counties from 1 a.m. Wednesday to 1 a.m. Thursday.

Sometime late Wednesday morning to midday, Simpson said he expects snow the become very heavy and stay that way for a few hours.

“Stronger winds just west of here will create blizzard conditions, and we may see near blizzard conditions in our western and northwestern counties,” Simpson said.

Snowfall rates of 1 inch to as much as 2 inches per hour are possible, especially north of Interstate 70. That will be more than road crews can keep up with, he said, possibly crippling the area for the rest of the day.

Also through morning, winds will increase to 30 mph and as high as 40 mph, causing significant blowing and drifting for the rest of Wednesday as well as evening.

Midday into early afternoon, ice southeast will change to snow.

Gradually later in the day the snow will become less heavy and taper through the evening, but road issues will continue, Simpson said.  (5 Day Forecast)

Expected snowfall totals:

• 6 inches to 10 inches north of I-70, with an isolated foot of accumulation possible. Significant blowing and drifting is very possible.
• 4 inches to 8 inches in the areas of Dayton and Springfield, as well as Preble and Butler counties.
• 2 inches to 4 inches, with ice in the morning, for Greene, Warren and Clinton counties.

Simpson is predicting that many counties eventually will be under Level 3 snow advisories. Snow advisories are declared by sheriffs, under state law.

Under Level 3, all roadways are closed to non-emergency personnel. No one should be driving unless absolutely necessary of a personal emergency exists. All employees should contact their employer to see if they should report to work. Anyone traveling on roads may be subject to arrest.

Under Level 2, roadways are deemed hazardous with blowing and drifting snow. Only those who feel it is necessary to drive should be out on the roads. People should contact their employer to see if they should report to work.

Under Level 1, roadways are snow covered and deemed hazardous.

In Indiana, a Level 1 travel advisory for the city of Richmond and Wayne County takes effect at 3 a.m. Wednesday, the county emergency management agency and sheriff’s office announced Tuesday evening. The advisory does not impose any restrictions on using county roads, but motorists have been advised that they will be traveling at their own risk, according to those offices.

Simpson said that by Thursday morning, the snow should be over and winds will be less. The day will be one of cleaning up and many businesses will still have trouble opening to start the day because of lingering travel issues.