Possibility for Snow Friday January 23rd in West Tennessee

WEDNESDAY JANUARY 21, 2015 - 1:12 P.M. CST

These next few days when I talk about the "S" word, I'm really talking about snow.

Recently, the weather has been absolutely gorgeous in West Tennessee with temperatures in the 50s and 60s under plenty of sunshine, but that could change drastically by the end of the workweek.

One of the most important tools meteorologist will use to create a forecast is called a computer model. There are several different types, and when computer models align showing similar information in their forecast, our confidence in our own forecast, based on those models, will increase. In baseball, it's three strikes and you're out but in weather I'm going to tell you that it's three strikes and you're in!

Strike 1
Yesterday, there was a computer model called the NAM (North American Model) suggesting the potential for snow on Friday in West Tennessee. The setup on Friday is relatively clear - an area of low pressure will be placed in the southeast United States with surface winds wrapping around counter clockwise, causing northerly winds and colder air to move into the Mid-South on Friday afternoon and evening. The NAM suggested that moisture associated with this area of low pressure would fall as a rain snow mix.

Here's a rendition of this setup based on the European model -

Temperatures that are blue, are below freezing - they're shown here in degrees celsius.

Strike 2
It's worth mentioning, at this point that today the NAM isn't the only model suggesting a potential for the cold air to interact with moisture present to cause snow to fall in West Tennessee. Now that there are others, there's slightly higher confidence that snow will fall Friday afternoon and evening.

Here's a look at those different models where green, yellow, and red colors show rain, but purple indicates wintry mix and blue indicates snow.

GFS (Global Forecast System)

GEM (Canadian)

NAM 4km (North American Model)

The NAM 4km has a higher resolution and can pick up on scattered showers more easily than the GFS or GEM models. At this point, all three of these models show a possibility for rain to change to snow or a wintry mix after 12pm Friday and last into the evening.

Strike 3
Tomorrow, we'll revisit some of these computer models and watch for any changes to the forecast. If they continue to show the chance for snow, then that will be strike 3, we'll be more confident with a forecast including wintry weather Friday afternoon and evening, and we'll issue a snowfall forecast map. At this point, while snow is possible, I think if we see any, it will be light and have a fairly hard time sticking at first given the warm weather we've had lately.

I'll keep you posted!