Today's Weather Discussion: Freezing Rain
Tuesday, December 14:
An unwelcome foe appears to be ready to return and bully the region again on Wednesday and Thursday....freezing rain. Just the sound of the word brings back all sorts of bad memories from January 2009, but let me start with the good news first.....this event is not going to be anywhere close to what we dealt with during Winter Storm '09. Back then, parts of the area received up to an over 2" of ice accumulation.....whereas tomorrow and Thursday's event likely will bring between 0.1" and 0.2" of ice. This event will result in some travel issues, but the threat for damaging ice accumulation to trees and power lines appears to be low.
A Winter Weather Advisory is in effect for all of the Local 6 region from noon Wednesday until 9AM Thursday. To read the advisory from the NWS, click here.
For more on the setup tomorrow, the National Weather Service in Paducah held a conference call today and created some helpful visuals showing when precip should arrive, what kind of precip will fall, and how much is expected. To see those graphics, click here.
Here's a summary of the situation: By Wednesday afternoon, an area of low pressure will be sitting out near Oklahoma City, with a warm front extending from the low through central Arkansas and down toward the MS river delta. A pool of cold, sub-freezing air will still be holding on over the Local 6 region, with warmer, moist air coming in from the south over the top of the cold air....a situation known as "overrunning". Here's a look at the setup as of Wed. 6PM:
As the precipitation begins Wednesday,with temperatures running colder north and slightly warmer south, we may be looking a scenario where we could have a mix of snow, sleet, and freezing rain.....with northern locations more likely to see snow, and southern sections more likely to see sleet and/or freezing rain. With our region covering four states, it's very difficult to nail down exactly what type of precip will be falling at a given point at a given time. These scenarios are always difficult to provide specific forecasts for because they are dependent upon changing temperatures both at the surface and in the lower levels of the atmosphere up above. Here is a graphic that may help you visualize our setup for this event a little better:
With this image above, imagine the right side of the image is north, and the left side is farther south, closer to the warm front. On the right side (north), the entire atmosphere from top to bottom is below freezing, so you get snow. Go a little farther left (south), and in the mid-levels of the atmosphere, there is a very thin layer of air above freezing.....this causes the snow at the top of the atmosphere to melt, then it falls back into the pool of freezing air at the surface....resulting in sleet. Move just slightly farther left (south), and the elevated layer of warm air is thicker. This causes the snow up top to completely melt and fall as rain.....only to freeze on contact at the surface, which is still colder than 32. This is freezing rain. Tomorrow's forecast setup will look very similar to this north to south across our region.