A cold winter storm is bearing down on Arizona, which means possible rain for the Phoenix metro area and snow in the high country. The system will bring some "bitterly cold" air down from the northwest, according to 3TV meteorologist April Warnecke. It also will pick up some moisture as it heads our way. The National Weather Service issued winter storm warnings for much of the state beginning tonight and running into late Thursday.

Rain could start in the Valley Wednesday morning. Snow could start in the high country as early as Tuesday night. According to the National Weather Service, widespread snow will increase from west to east across northern Arizona on Wednesday, with the heaviest snowfall expected Wednesday evening.

Snow levels could fall to 2,000 feet and a dusting is still possible Thursday morning in those higher elevations near the Valley like Cave Creek and Wickenburg.

The Arizona Department of Transportation is using the clear conditions today to prepare to deal with whatever Mother Nature brings.

More than 200 snow plows are on standby across the state, ADOT spokesman Doug Nintzel said.

"A lot of people focus on Flagstaff and that area, but we certainly have the Globe area, Show Low. All of those crews today are going to be taking advantage of the nicer weather to get ready for the storm's arrival," he explained.

Nintzel said it is always difficult to predict conditions on the highways when a storm rolls through, but he had some advice for drivers.

"If you can avoid the height of this particular storm that's coming in, let the storm pass through," he said. "Let our plow crews clear the highways."

If you do find yourself sharing the roadway with a plow, be sure to hang back at least four car lengths.

Whether you get ahead of it or wait until it has passed, Nintzel said you need to be prepared for winter driving conditions.

"You don't want to just head out into a storm unprepared," he said.

To that end, Nintzel recommended drivers prepare an emergency kit, including a first-aid kit, a flashlight and batteries, blankets, an ice scraper, a change of clothes and snacks and bottled water.

"You want to have two hours' or more worth of supplies so you know you can get through a situation," he said.

Nintzel said you can keep track of what's happening on the highways via the agency's Twitter account -- @ArizonaDOT. They will be using the hashtag #NewYearsStorm.

"This is going to be a good storm for northern Arizona," Warnecke said.

Forecasters say snowfall will range from 2 to 6 inches in areas between 3,500 and 5,000 feet of elevation and 6 to 10 inches in areas above 5,000 feet. Locally higher amounts are expected in some areas.

Flagstaff is expected to get 9 to 13 inches of snow, Prescott 4 to 8 inches and Sedona 3 to 6 inches.

Rain chances are not quite as high now for the Valley tomorrow. There is still a chance for rain, but those chances are down, as are forecast rainfall totals.

When the storm system clear out Thursday -- News Year's Day -- it will leave cold temperatures behind.

Freeze Warnings are likely with some Valley spots likely to fall off to the mid-20s by Friday morning.

Additional Arizona highways closing for the winter

More highways in Arizona's high country are closing for the winter.A portion of State Route 366 leading up Mount Graham was closed Nov. 15, and State Route 67 between Jacob Lake and the Grand Canyon's north rim closed on Dec. 1.

Another highway already closed for the winter is State Route 473 to Hawley Lake. It originally was closed Oct. 16 for draining of the lake and dam repairs. ADOT says sections of two additional highways are closing Tuesday.

One section being closed is State Route 261 between Big Lake and the State Route 260 junction. The other is State Route 273 between Sunrise Park Resort and Big Lake. ADOT says the routes will reopen in the spring.