SPC increases severe risk for Wednesday: Southern MS/AL/LA Weather Forecast – 12/13/22

Quick reminder: We have a new page to get the latest current conditions, forecast info and a look at the radar: https://www.nickelblock.com/local-detailed-forecast/

We are still monitoring the potential for severe weather. The SPC has increased the Risk for Wednesday (as expected) to include an Enhanced Risk for Mississippi and Alabama.

Today
Tomorrow

Both of these come with a 10-percent tornado risk in that Enhanced Risk area that is hatched with an increased threat for EF2 or stronger tornadoes.

And based on some of the higher-resolution model guidance, it looks like parts of Mississippi will actually see two round of potentially significant severe weather during the next 48 hours.

Here is an updated look at the timeline:

Keep in mind that the higher risk for severe weather overnight or before dawn will be west of I-55. There is a lower potential east of I-55, but the potential isn’t zero.

Int he afternoon the higher risk shifts to the east of I-55, with the lower potential west of I-55.

Here is a look at the HRRR model:

I tried something new today and I took a look at all of the higher resolution model guidance and asked the computer to build a composite of all of the potential Updraft Helicity streaks. Recall that the Updraft Helicity streaks are when we already asked the computer for a favor and pick out where it thinks the strongest storms will be, based on the atmospheric parameters in place.

So this is a bit of a two’fer. We are asking the computers “where will the strongest storms be” across five different computer models. Then we are asking the computers to take that info and make a composite of all five of those models into one single map.

This has limitations, though. As it can only show data out through 6p on Wednesday. So we are missing a few hours of data, so if you live in southeast Mississippi or Alabama, this will miss a lot of the potentials for you.

But here is that map:

Updraft Helicity Streaks composite from the HRW, HRRR and NAM3km between 6a Tuesday and 6p Wednesday

Because it is a composite, it will average out a lot of the brighter colors (which would indicate the strongest-of-the-strong) but you do see a pretty wide swatch of storms from Louisiana through south Mississippi – from about Baton Rouge NE toward Meridian. And it looks like Smith County, MS has the darkest shading.

If you look at just the HRW-suite of models, you get this map:

Updraft Helicity Streaks composite from the HRW between 6a Tuesday and 6p Wednesday

And I wanted to really drive the point home here that we are asking the computers to do multiple things – build us something, then build us something from what it just built. So there is plenty of room for error. But I think this gives us a good ‘first look’ at the potentials for the next 48 hours.



DAY TO DAY FORECAST

Today
Mostly cloudy. Patchy fog this morning. Highs in the lower 70s. Breezy. Southeast winds 5 to 10 mph with gusts up to 25 mph.

Tonight
Cloudy. Storms possible this evening – mainly from I-55 westward. Lows in the mid 60s. Breezy. Southeast winds 5 to 10 mph with gusts up to 25 mph. Chance of rain 40 percent.

Wednesday
Cloudy with storms likely. Severe weather possible. Highs in the mid 70s. Breezy. South winds 10 to 15 mph with gusts up to 35 mph. Chance of rain 90 percent.

Wednesday Night
Mostly cloudy with storms ending before midnight. Lows in the mid 40s. Breezy. West winds 5 to 10 mph with gusts up to 35 mph, becoming northwest with gusts up to 20 mph after midnight. Chance of rain 40 percent.

Thursday
Sunny. Highs in the lower 60s.

Thursday Night
Clear. Lows in the upper 30s.

Friday
Sunny. Highs in the upper 50s.

Friday Night
Partly cloudy. Lows in the upper 30s.

Saturday
Mostly sunny. Highs in the mid 50s.

Saturday Night
Partly cloudy. A slight chance of rain in the evening. Lows in the mid 30s. Chance of rain 20 percent.

Sunday
Sunny. Highs in the mid 50s.

Sunday Night
Partly cloudy. Lows in the upper 30s.

Monday
Mostly cloudy. A 30 percent chance of showers. Highs in the upper 50s.



Author of the article:


Nick Lilja

Nick is former television meteorologist with stints in Amarillo and Hattiesburg. During his time in Hattiesburg, he was also an adjunct professor at the University of Southern Mississippi. He is a graduate of both Oregon State and Syracuse University that now calls Houston home. Now that he is retired from TV, he maintains this blog in his spare time.