No sneaux for south LA – Winter Weather Statement from NWS

Special Weather Statement issued December 19 at 8:06AM CST by NWS New Orleans LA

An extremely cold air mass is expected to surge towards the Gulf coast Thursday and Thursday Night and bring a multitude of hazardous conditions to the area. Hard Freeze, very strong winds, and dangerous Wind Chill conditions would begin as early as late Thursday night and we will continue to deal with the Arctic air through Christmas Day. Now is the time to start taking measures to protect your family, pets, friends, property, and yourself from the likelihood of extreme and prolonged freezing conditions for southern Mississippi and southeast Louisiana.

What will be the impacts: – Extreme cold – Very strong and possibly damaging wind gusts – Dangerous wind chills – Hazardous Driving conditions due to winds

An Arctic airmass surging south out of Canada and across the central United States will quickly move into the Lower Mississippi Valley Thursday night. The cold front is expected to move into southwestern Mississippi and Southeast Louisiana during the evening hours with temperatures dropping 20 to 30 degrees or more in only a few hours. Temperatures will continue to plummet through the early morning hours with almost the entire area below freezing around sunrise. Not only will the temperatures plunge but this will be accompanied by very strong winds and wind chill readings in the teens to single digits are now EXPECTED! There is even an outside chance of a few locations experiencing a wind chill below zero!

The wind chill has no impact on pipes but for people and pets the rapidly moving air speeds up the heat loss over our bodies and can quickly lead to hypothermia. As for pipes, plants, and property, temperatures will struggle to get above freezing, if they even do Friday, and there is a chance that many locations could be below freezing for 24 to possibly even more than 36 hours. And even if temperatures climb above freezing Friday or in southwestern Mississippi and the adjacent Louisiana parishes’ case Saturday, they will only be above 32 for a very short time.

Not until Christmas Day does it look like we will comfortably get above 32 degrees for much of the area and for more than a few hours.

We know many of you are thinking at least in the back of your head about winter precip. This is NOT a Winter Storm, it is strictly an Arctic Airmass and ALL of the impacts will be dealt by the temperatures and wind. That said there is a small chance of flurries at best right now on the very back end rain associated with the cold front Thursday night but this will lead to ZERO impacts. Do not, again do not concern yourself with flurries.

Here is the latest forecast for Friday, Saturday, and Sunday referencing highs, lows, and minimum apparent temperature (Wind Chill).
Morning Minimum Low – Afternoon High – Wind Chill
McComb Friday 15 29 0 Saturday 13 34 3 Sunday 18 40 11
Baton Rouge Friday 20 34 7 Saturday 17 38 9 Sunday 21 44 17
Slidell Friday 22 37 10 Saturday 16 39 8 Sunday 20 44 16
Poplarville Friday 18 32 6 Saturday 16 36 8 Sunday 20 41 14
New Orleans Friday 26 35 13 Saturday 24 38 15 Sunday 28 41 22
Houma Friday 24 37 11 Saturday 20 39 11 Sunday 24 43 18
Gulfport Friday 25 39 14 Saturday 19 41 9 Sunday 23 45 16
Pascagoula Friday 24 39 13 Saturday 16 39 6 Sunday 20 43 13

Yes, that is a forecast wind chill of ZERO at McComb and actually have a -2 wind chill currently forecast for Woodville, MS Friday morning.

The other high impact from the weather will be the winds. Immediately behind the cold front very strong winds out of the north-northwest will develop and continue to strengthen through the overnight hours and remain quite strong through the day. Conditions will be quite favorable for winds to gust to and likely higher than 40 mph and this will have a good bit of impact on travel, especially for high profile vehicles along our major east to west highways where the winds will almost be perpendicular to the direction you are traveling. Any elevated roadways (which there are a lot of) especially the Mississippi River and Pearl River bridges along with the Causeway and Twin Span will be dealing with very hazardous winds.

If that wasn’t enough there will likely be quite a bit of people traveling for the Christmas holidays only leading to greater congestion on the roads with these strong winds. Please plan accordingly and allow for extra time especially if you travel across any roads that may close due to high winds like the Causeway.

Also don’t get caught on the roads by traffic or an accident and stuck in the very cold air. With most people not used to packing for cold weather while making even a small trip down I-10, it would be a great idea to pack an emergency kit with a way to keep warm just in case. You can never be too careful especially when dealing with conditions we are just not used to down here.

Some historical information to relate to prior to our cold event. Every weather event is different and they should all be treated as such but for at least some modern reference, here are a few Arctic events to relate to; February 2nd through 5th 1996, January 8th through 11th, 2010, and more recently is February 15th through 17th 2021. However, this airmass appears to be more potent than the 2010 and 2021 events.

Also we did not compare this to the Jan 17th and 18th Winter event; yes it was cold and it appears that we even had one Co-Op site record 9 degrees for a low on the 17th, Poplarville Exp Station. This station has a continuous data history back 1919 and partial data back to 1896. This was part of a major winter storms for the deep south that brought snow and ice across the region and closed I-10 from Lafayette to Slidell, LA and our airmass late this week will not be a winter storm, just a very cold airmass.

As for reference to the Holiday time frame, surprisingly there are 2 of the more historic events and not just for our area that occurred during this time; 1983 December 23rd through 26th and 1989 December 22nd through 25th events. These two are quite historic events but at this time we are not anticipating testing those 2 Arctic events. The 1989 Arctic airmass still holds numerous records across a good portion of the US including here where single digits were recorded in more than just a few places. We would have to go back to 1899 to see temperatures recorded lower than 1989 in much of the area over a multi day stretch. 1985 saw another historic cold front for our area which did set some all time record lows but it was a short lived airmass with highs back in the 50s the next day.

Shared from the Terrebonne OHSEP app at https://apps.myocv.com/share/a60670359