SOUTH MISSISSIPPI (WLOX) - As 2017 ends, it looks like Mother Nature wants to kick off 2018 with frigid temperatures and the potential for a wintry mix of freezing rain, sleet and snow. But, there is still a lot of uncertainly regarding the chance for wintry precipitation, if any.
VIDEO: One minute update
Over the past several days, almost all global forecast models have been trending towards a big cool-down for the eastern two-thirds of the United States just in time for the new year. This includes South Mississippi. The overall large-scale pattern is locked in. But, the smaller details, such as the arrival time of the coldest air and how much moisture is available, in each model run have not been worked out.
The Global Forecast System (GFS model) keeps trending towards the direction of rain mixing with freezing rain, sleet and snow north of I-10 on the morning of New Year's Day. It keeps the moisture around long enough for the cold air to interact with it.
The ECMWF (European Model) is much drier and has all the moisture clearing out before the coldest air arrives.
So why do they disagree?
Meteorologist use models make forecasts. These models are made up of countless equations that govern the physical and thermodynamic properties of the atmosphere. Weather observations are plugged into those equations and super computers run calculations. Each time a new calculation comes out, it is called a model run. Each model run is an interpretation of what the atmosphere may look like in the future based on the observations plugged into it. This is known as numerical weather prediction and it turns out, you can get reliable forecasts 3 to 5 days out. Beyond that time frame, the calculations develop large errors and models start to disagree with one another.
Both models indicate very cold air for the start of 2018, but disagree on the arrival times of the coldest air and how long the moisture hangs around. As of now, winter weather with significant impacts to travel are not expected. But, if you have travel plans for New Year's Eve celebrations, keep checking back on the forecast by going to your WLOX Weather App or by checking our Weather Page.