For Christmas travelers who plan to go by something other than a one-horse open sleigh, timing may be important.
Weather forecasters say Pittsburgh may get its first measurable snowfall since early March starting on Friday and possibly lingering into Saturday, just when people are hitting the road to join an estimated 93.3 million Americans who will travel 50 miles or more for the holidays.
The travel forecast by AAA, which covers the period starting Friday and continuing to New Year's Day, represents a 1.6 percent increase compared with the previous year.
Ruth Nagy, managing director of travel operations for AAA East Central, said she expects most people to go on Saturday and Sunday but thinks the holiday rush will be spread out a bit.
"There's a lot of different options this year because the holiday falls on the Tuesday," she said.
Ms. Nagy recommended that travelers, whether driving or flying, stay aware of weather conditions and plan around any forecast of bad weather. That might include an alternate route around a snowstorm -- even if it adds an hour or two it might be better than trying to drive through the heaviest weather. Air travelers should keep their airline's toll-free phone number handy -- it often is easier to rebook a flight by phone than at airport counters.
In addition to its travel forecast, AAA East Central on Tuesday issued what might be called its misfortune forecast, saying it expects to rescue 39,000 stranded motorists in its service area, which includes Western Pennsylvania, south-central Ohio, most of West Virginia and four counties in western New York.
Steve Popovich, managing director for automotive services, said the single most troublesome item will be dead batteries. "We had a very hot summer. Heat plays havoc with lead-acid batteries," he said.
In addition to having the battery looked at, AAA recommends checking antifreeze, windshield wipers and fluid, tire pressure and tread, and engine belts and hoses.
AAA estimates it will answer 6,500 calls for cars that won't start; change 6,000 flat tires; pull 2,000 cars out of snow or mud; and help retrieve 4,800 sets of keys that will be locked inside vehicles, no doubt by people with visions of sugarplums dancing in their heads.
Mr. Popovich said AAA will have its call centers fully staffed and "quite an army of trucks" out. Depending on the seriousness of the call -- a driver who is stuck on a road gets priority over someone whose car dies in their driveway -- the agency tries to respond to all calls within 60 minutes.
Roughly 90 percent of those who travel during the holidays will do so by automobile, AAA forecasts. While the average price of a gallon of regular gasoline in Pittsburgh has fallen to $3.48 after reaching $3.65 last month, it is still higher than last year's average of $3.33, said Bevi Powell, AAA vice president of community relations.
National Weather Service meteorologist John Darnley said forecast models suggest that Pittsburgh will get an inch or two of snow Friday into Saturday morning, with higher totals north toward the snow manufacturer known as Lake Erie.
"I'd recommend leaving early Friday rather than later Friday or later Saturday rather than earlier Saturday," he said.
After Saturday, several days of dry and seasonable weather are expected before a midweek storm brings the potential for rain, Mr. Darnley said.
No white Christmas then?
"Not looking like it," he said.