Update On Snow Potential

The system that will move through the area overnight won't result in much snow at all for central Virginia, and if you sleep in, you'll likely miss it. The lift associated with the upper trough will weaken and accelerate as it moves over Virginia, giving us very little time to generate a good snow producing atmosphere. Throw in temperatures at the surface that will be a little above freezing, and you can plan on a very uneventful Friday. It will, however, be windy and cold for the remainder of the day, setting us up for a very cold weekend. The scenario next week continues to look promising for wintry weather, and the last few model runs have trended colder, making snow the predominant mode of precip. Our chance(s) for precipitation will depend on the timing and position of several upper-level disturbances embedded in west-southwesterly mid-level flow. Here's a snapshot of the GFS solution early next week showing two distinct upper-level waves over the Texas Panhandle and northern Idaho.



The evolution of these waves continues to change, which will change the timing and amount of precipitation we see. One thing that has been pretty consistent through all of the models has been the strength of cold high pressure that will move into the Northeast and Mid-Atlantic. While it doesn't appear like we'll see a major snowstorm, we could end up with several different episodes of winter weather next week. We'll continue to update you here and on CBS 6.

2010 In Three-Way Tie For Hottest Year On Record

It's official: 2010 is in a three-way tie with 1998 and 2005 for the globally hottest year on record. The U.N. weather agency released their final results on data analyzed from last year today, which "confirm the Earth's significant long-term warming trend," according to World Meteorological Organization Secretary-General Michel Jarraud. This data set (global land and sea) is compiled from two U.S. sources (NASA and NCDC) and the UK Met Office Hadley Centre/Climatic Research Unit. Last year's global average temperature was 0.95 degrees Fahrenheit above the 1961-90 mean, with no significant statistical difference between 2010's average and those of 1998 and 2005.

In the U.S., we experienced our 23rd warmest year on record (for the contiguous states). You may remember Richmond International Airport recorded its most 100 degree days ever at 10 (7 in July, 3 in June).

In other news from this data, 2010 was the global wettest year on record, based on global average precipitation.

Update on Friday's Snow Potential

An upper-level trough currently (at the time of this entry) located over the Rockies will move eastward and deepen over the next 48 hours. Strong lift associated with the approaching trough will cause a broad area of snow and rain to develop and move through the Mid-Atlantic region. Temperature profiles in central Virginia will be supportive of snow as the primary precipitation type, but this snow will be falling into surface temperatures that are just slightly above freezing. It's common to see snow in central VA with above freezing surface temps when you have sub-freezing conditions just off the surface, it just melts on contact without accumulating. Friday will be a situation where I think we'll see snow (if you are up early), but any accumulation will be limited to grassy surfaces. Depending upon the relationship between the temp and dewpoint at the time the precip begins, there will be the potential for areas north and west of Richmond to evaporatively cool to the freezing mark at the surface. These areas will have the best potential to see slick roads. Whatever we see will move out of the area early in the morning, and we'll have a sunny, windy, and cold afternoon.

It continues to look like our best shot at seeing a significant winter weather event (one that would result in school and business closings) will be on Tuesday. This next system will likely bring a mix of precipitation to central VA, and in an order that will keep us pretty busy. The combination of a strong retreating surface high over New England, and several upper-level disturbances embedded in southwesterly flow will make it very interesting. Right now it looks like it will start as snow late Monday, then go to a mix of sleet and freezing rain, then over to all rain, and then back to snow before ending Wednesday morning. I'll have more updates on this system in the next few days.