Just in time for the weekend, Arctic air has settled into the Southeast U.S., and a strong jet stream disturbance is generating a storm along the central Gulf Coast. That storm is slated to bring snow and ice, making for treacherous conditions across the region.

On Friday afternoon, snow and ice were already falling as far south as Alabama and Mississippi. The storm will intensify Friday night, and bring heavy snow and some ice to parts of northern Georgia, the Carolinas, and southeastern Virginia.

The Northeast will also feel the effects of the storm, though it won’t be a typical nor’easter. This storm is expected to hover a little bit farther offshore, allowing snow to fall in areas right on the coast. This means accumulating snow will fall along the New Jersey Shore, eastern Long Island, and Cape Cod on Saturday. The larger cities a bit farther west, such as Philadelphia, New York, and Boston will get much less snow, if any at all.

The heaviest precipitation will fall in the Southeast on Friday night and Saturday. Some of the forecasts from the National Weather Service:
 

  • Birmingham: 1-3 inches of snow, with some ice mixing in
  • Atlanta: 2-5 inches of snow, with some ice mixing in
  • Charlotte: 4-7 inches of snow
  • Raleigh: 4-8 inches inches of snow
  • Richmond: 4-8 inches of snow
  • Norfolk: 8-12 inches of snow, with some ice mixing in

Raleigh averages only about 6 inches of snow annually, while Charlotte averages about 4 inches.

The precise track of a storm and the availability of cold air are the two primary factors driving how much snow falls. And while the amount of cold air will be on the gradual decline in a warming world, it does not mean snowstorms will cease to exist.  

In locations that are accustomed to getting snow during the winter, the total amount of snow each year is already decreasing as the planet warms from increasing greenhouse gases; the percentage of precipitation falling as snow is on the decline, with more of it falling as rain.

However, some individual snowstorms, paradoxically, may bring larger snow totals. At higher temperatures, evaporation increases, which means more moisture is available to produce precipitation. This relationship holds at low temperatures as well as at high temperatures. For example, if all else were equal, a snowstorm at 30°F would produce more snow than a storm at 20°F.

There is already evidence of this occurring. In several Northeast cities where records have been kept regularly since the late 19th century, the heaviest snowstorms have occurred in recent years. Consider some of the statistics gathered last year by the Washington Post’s Capital Weather Gang:
 

  • Seven of Washington’s top 10 snowstorms since 1889 have come since 1979.
  • Seven of Baltimore’s 10 biggest snowstorms have also come since 1979. Four of its top 5 have come since 1996.
  • All five of Philadelphia’s highest snowfalls have occurred since 1983, and its top three have come since 1996.
  • In New York City, seven of the nine biggest snows have occurred since 1996. Three of the top five have come since 2006.
  • Half of Boston’s top 10 snows have come since 2003. Eight of its top 10 have come since 1978.

So while the average amount of snow each season may be on the decline with climate change, there may still be something left for snow lovers to cling to in the years to come.