Tuesday, December 22, 2009

Tis the Season… for Nor’easters?

What will this winter be like? If the current weather pattern continues, the East Coast will certainly be stormy. Friday night through Saturday (December 18-19), Virginia experienced yet another intense Nor’easter (see blog of November 12). This one dumped huge amounts of snow over the central and western parts of the state.
Whether Virginia gets rain or snow from a winter Nor’easter depends largely on the track of the storm. A more westerly inland track will pull in warmer ocean air and Virginia will usually get rain. If the center of the storm stays just off the coast, cold air is often pulled in behind the storm and Virginia can get snow, sometimes lots of it. Nor’easters can intensify to hurricane strength and bring extremely high winds, coastal flooding, beach erosion, and heavy rain or snow to the mid-Atlantic and Northeast states. In the satellite picture above, note the hurricane-like eye in the center of this intense storm.
In addition to the heavy snow and gusty winds, this storm also included thundersnow. Thundersnow occurs only rarely and is basically a winter thunderstorm with falling snow instead of the usual rain. The lightning is nearly blinding due to its reflection off the white snowflakes, and the sound of the thunder is acoustically suppressed by the snowfall. Normally, thunder can be heard many kilometers away from a thunderstorm, but the thunder from thundersnow can only be heard 2 or 3 kilometers away. We had thundersnow at my house just after midnight on the 19th with at least two very bright lightning strikes and accompanying thunder.
How much snow did you get from this storm? I had 1 foot at my house in Midlothian, about 15 miles west of Richmond.


Rich Conti said...

Is there an easy way to convert inches of snowfall to inches of rain?

Liz Mebane said...

The snow to rain conversion varies widely depending on how wet the snow is. Here in Virginia our snow is usually wet and averages to 5-6 inches of snow per inch of rain. Very dry snow can be as much as 20 inches per inch of rain. The average is about 10 inches per inch of rain.