NEW ORLEANS — The Storm Prediction Center continues to have our entire viewing area in an Enhanced risk of severe weather for this afternoon and evening.
The enhanced risk is a level 3 out of 5 for the chance of severe weather occurring. The "hatched" area within the enhanced risk which indicates a greater potential for "significant" severe weather is not located from the Northshore and South Mississippi. Long-tracked, strong tornadoes could be a danger in that area.
Either way, we do not see this type of risk category for southeast Louisiana very often. When we do, there is a greater chance for numerous strong storms and several warnings for severe weather. Additionally, these storms will produce damaging winds, large hail and a few tornadoes that could be stronger than normal for our area (possibly EF-2 (110+ mph) or greater).
A cold front and area of low pressure will move across Louisiana during the day. It will be warm with highs around 80, very humid and windy (20-30 mph) ahead of the front. When you combine those ingredients with strong upper-level winds and a trough of low pressure you get strong to severe storms.
There are many needed ingredients to create an optimal environment for widespread severe weather, and that looks to all be coming into place for Thursday. The severe set up over the region is far more conducive for the development of severe storms than we have seen in the last few years.
A squall line will be weakening as it moves out of Texas this morning. It will track across Louisiana all day and it will strengthen once it moves into the Lafayette area. These storms will likely have some damaging winds and a few tornadoes. Ahead of the line there will be individual storms known as supercells or rotating thunderstorms. These are the storms that could produce tornadoes, some strong, as they move from SW to NE across the area. We will have to watch to see where they develop and the impact on the New Orleans area.
Here is the tentative time line for Today:
11 am – 2 pm: A few isolated storms could form ahead of the main system around the Baton Rouge area. There may not be a lot of these early storms, but any that form will have the potential to rotate and turn strong to severe. These supercells are the ones that could produce tornadoes and large hail.
2 pm – 8 pm: The bulk of the strong to severe storms will happen during this time. First from the individual supercells, and then from a squall line moving east across the area. The supercells could produce tornadoes that are strong. The line will likely contain storms with straight-line damaging winds and a few tornadoes. Heavy rain is also expected and we could see street flooding.
8 pm – 11 pm: The severe threat will be over for SE LA around 8 PM, but it will continue for the MS Coast until 10 PM. The rain will gradually come to an end from west to east by 11 PM.
Since it will be very humid, we will have a greater chance for heavy rain. Rain totals will be around 1 to 3 inches. We have been dry lately, so we are not expecting anything more than usual street flooding.
Once the front moves through, we will have some lingering clouds and a few showers on Good Friday. It will become much cooler, windy and less humid too.