Winter Storm Watch from Midnight (12 a.m. Friday) to 6 p.m. Friday

NOTE: This blog post is pertaining to a chance for snow and ice that is forecast 

to occur between tonight, Thursday, January 11th, 2018 and Friday, January 12th, 2018.

Over the next 24-36 hours, West Tennessee will see rain transition to freezing rain, then sleet, and finally snow. This will be the first significant impact we'll face this winter season, so it's important that we get prepared today!

SET-UP
Below, is a chart showing the different pressure systems and fronts in the United States as of this morning. Our storm is the "L" in western Oklahoma, and it's attached to a long cold front extending from Mexico to Canada. Both of these features will be in the Mid-South by tonight and will continue to be key players in the forecast throughout the day tomorrow.

Here's an idea for where that low pressure system will go over the next few days. We'll be on the northwest side of the low pressure system Friday morning. That, typically, is where you see the higher snowfall amounts accumulate, but the cold air from the Northern Plains will need to catch up to it quickly enough to cause a change over to snow.



FORECAST
The general trend in the latest model data this morning (Thursday, January 11th 8:00 a.m.) is that we'll be dealing with rain showers (some heavy) off and on throughout the day today into the evening. Between 3 p.m. Thursday afternoon, and 3 a.m. Friday morning, West Tennessee will have some scattered thunderstorms in the Mid-South, but because we won't have a lot of energy in the atmosphere, severe weather remains unlikely.

West Tennessee generally just has a chance for a few thunderstorms and strong thunderstorms are not likely. However, because of how muggy it is out there, I do expect some pockets of heavy rain to take place this afternoon, evening, and overnight.

After the cold front starts to move in, we'll change to ice. The animation below (midnight tonight through 9 p.m. Friday) shows that changeover happening in Jackson between 3 a.m. and 6 a.m. Friday. The green color on the map below represents rain, while the reddish and purple colors represent ice, and blue is snow.

The freezing rain and sleet will not be constant Friday morning but could be heavy at times in West Tennessee. Where exactly depends on the path of the storm but I suspect our viewing area will be ground zero for some of the highest ice accumulations. That said, this still doesn't appear to be a major winter storm for the Mid-South. The map below shows only a 30-40% chance for a quarter of an inch of ice to accumulate on Friday in the dark green area.

The trend between yesterday afternoon and this morning also points to lower snowfall totals, but there are still some models putting out high amounts. Again, this all hinges on how quickly the cold air reaches us! Just take a look at this one particular model, the North American Model, and see the differences in output as it's refreshed 5 times since yesterday.

 

Both in placement, and amounts, this model has not been consistent with where we will get accumulating snow. However, looking at the data from different models as a whole, it still looks like Martin, Huntingdon, Paris, and Camden stand the best chance for the higher totals. The map below shows a 40-50% chance for 2" of snow in the blue area over Weakley, Henry, and Benton counties where the rest of West Tennessee is only looking at a 20-40% chance for that occurring.

After transitioning to snow Friday afternoon, we'll finish all forms of precipitation by Friday evening. At this point, I think we're certainly looking at a coating to 2" of snow on grassy surfaces in West Tennessee by the end of the day on Friday. There could be isolated totals of 2"-3" in northwest Tennessee as well, especially for those living near the Tennessee River.

For Jackson, I'm expecting a coating to 2". This graph shows most of this particular family of weather models giving us a minimum of no snow at all to 3-4" but I think that range is an outlier for us right now. The black line represents the model average showing 0.5" of snow.

FINAL DETAILS
I try not to predict unpredictable human behavior, but I'm thinking administrators will issue school closures for tomorrow.

It's worth mentioning that overall, whatever falls from the sky on Friday, will eventually be met with very windy conditions. That means a wind chill at or below 15°F all day long. When those windy conditions with gusts up to 40 miles per hour meet up with ice-laden tree branches, I think we'll have power outages - spotty not widespread. We'll have some sunshine this weekend but below freezing temperatures this weekend with partly to mostly cloudy skies will limit melting over the weekend too.


Summary

• Rain changes to ice overnight tonight falling by 6 a.m. at the latest for most of West Tennessee. Despite the sharp drop in temperature, severe weather isn't expected overnight but we'll have some thunderstorms.
• Freezing rain and sleet will be scattered Friday morning before changing to snow Friday afternoon.
• A coating to 0.25" of freezing rain on tree branches and power lines
• A coating to 2" of snow is expected with isolated totals of 2"-3" in northwest Tennessee near the Tennessee River are possible (mainly in Weakley, Henry, Benton, and Carroll counties)
• Friday will be cold and very windy with spotty power outages likely

We'll be updating our snow and ice totals forecast before MidDay and Noon with Meteorologist Moe Shamell, adjusting the timeline for the onset snow and ice, as well as revising the various impacts. Tune in to WBBJ 7 Eyewitness News for the latest forecast!