Winter Weather Potential from Sunday - President's Day

Over the past few days, the forecast has changed quite a bit. So here's where we stand now...

The forecast for today kept getting warmer and now it looks like we could have a good shot at 50°F around lunchtime. However, the warm weather will last very briefly before it gets cold and windy! Sustained wind speeds will peak between 20 and 30 miles per hour this afternoon with gusts up to 40 at times. It's mainly the western half of West Tennessee that will be dealing with the strongest winds which will begin out of the west and shift to be out of the north after a cold front comes through.

That cold front is going to bring dangerously cold air to the region. Sunday morning, wind chills could be in the single digits with readings a few degrees below zero possible too.

This cold air isn't just going to come in feeling frigid, but will also be very dry and THAT is one of the issues that's going to make this forecast so difficult. With drier air, the ratio between inches of liquid equivalent and inches of snow increases exponentially. In West Tennessee, we typically have a 10:1 ratio, which means that for every inch of water that falls, we get 10 inches of snow. However, this time, the snow ratio could be higher than that since the incoming air will be so dry.

Let's look at that with some actual numbers...

This is our in house computer model's projections for snowfall totals based on a 10:1 (normal) ratio for snow that starts Sunday night and lasts into Monday morning. Most of the values are between a trace and 3". (By the way, this is just a model projection and it has its flaws)

By comparison, this is what the same model's projection looks like based on a 15:1 (drier air) ratio for the same time frame. It's nearly an inch different in some areas! Watching the air move in from the north behind the incoming cold front is going to be key with forecasting snowfall totals.

Right now, we're sticking with a trace to 3" across the area - going with a snowfall ratio that's just a little bit higher than normal. It's worth mentioning at this point, that the reason why we're going lower in southernmost parts of West Tennessee, is because there's a potential for sleet to be mixed in with the snow in those areas. Most parts of West Tennessee should see only snow, but ice could mix in with the snow at first in southwest Tennessee.

It's possible that later today or tomorrow, the National Weather Service will issue winter weather alerts for West Tennessee so make sure you're familiar with the terms below and what they mean.

Winter storm watches are issued well in advance of an event when conditions are possible. On the other hand, advisories and warnings are when the event is imminent - soon to occur or already occurring.

Incidentally, the next week as a whole will be very cold. We may even get another chance for snow on Thursday! There's still some uncertainty in the forecast though, so make sure to watch Good Morning West Tennessee with meteorologist Eddie Holmes for the latest. We'll keep you updated throughout the weekend!

Update: Light Snow Expected Tonight (Wednesday, February 4th, 2015)

There doesn't appear to be a need to change our forecast from last night. 

If you're trying to plan out Thursday morning take this into consideration - remember the snow we got on the night of Friday January 23rd? It was only a dusting. That's about how much we're expecting tonight, if not just a little bit more.

Potential impacts:

• With ground temperatures still above freezing, it's likely that any snow that melts on contact will refreeze as temperatures drop. Thursday morning, area bridges may have ice on them and so you'll want to watch those areas closely. Give yourself extra distance between your car and the car in front of you.
• Your car doors are probably going to be difficult to open if your car isn't in a garage. Give yourself some extra time to take care of that tomorrow morning.
• It's going to be cold. Winds will be blowing out of the north between 10 and 20 miles per hour making it feel like it's in the single digits. Wear lots of layers!

We'll have more on this on WBBJ 7 Eyewitness News later tonight!

Potential Snowfall by Thursday, February 5, 2015

Tomorrow, February 4th is what we might consider the "mid-point" of Winter with half the season over and another half still to go. The first day of Spring in 2015 is on March 20th and for those wishing for warmer weather, it couldn't come a minute too soon!

Regarding the potential for snowfall in West Tennessee from Wednesday night into Thursday morning, don't expect a big storm. There's currently only a 10%-20% chance for 1" of snow to accumulate anywhere in West Tennessee. Those numbers aren't impressive so we shouldn't worry about getting a lot of snow with this system. Still, with a lack of snowfall removal resources in rural areas of West Tennessee, there's a potential for hazardous travel Thursday morning.

Our in-house computer model is showing a chance for at least a trace amount of snowfall as far south as into parts of northern Mississippi. However, with all precipitation expected to be falling very lightly, whether its snow or rain, I'm a bit skeptical that we'll see accumulation that far to the south. Considering there's still some uncertainty as to how warm/cold the atmosphere will be when precipitation starts, I think that most, if not all, of the sticking snow will be north of the Tennessee-Mississippi border.

Based on that computer model, these are the projected snowfall totals as of 6:30 p.m. Tuesday February 3rd, 2015 by noon on Thursday -

Currently, I'm leaning on the side of this snowfall resulting in a dusting across most of West Tennessee. Heavier amounts (basically a heavy dusting) will be possible in areas north of I-40.

In the worst-case scenario where the cold air gets here sooner than currently expected, we could see higher snowfall totals.

In that event, counties in northwest Tennessee especially those that border western Kentucky and southeast Missouri, could get 1"-2" of snow. Most of West Tennessee, including extreme northern portions of Mississippi, would get at least a trace of snowfall if that situation pans out.


 


We'll be monitoring this one closely, with another update coming out Wednesday morning.