Click HERE for an update concerning the severe weather threat today and tonight.
Changes from the previous update:
- The threat of severe weather has increased
- The area of greatest threat has increased
Overview:
WHAT: SLIGHT RISK to ENHANCED RISK of Severe Weather and MARGINAL RISK for Heavy Rain
WHEN: This afternoon into Thursday morning
WHERE: All of SE LA and southern MS
CONFIDENCE:
- We are confident (high) that thunderstorms will develop later today and impact the area through the night. Confidence is increasing in the risk strong and a few severe storms developing. Low confidence in exact timing as latest hi-resolution models are trying to indicate storms developing well ahead of the actual front early this afternoon leading to 2 separate rounds of storms.
- If strong to severe storms occur confidence is high that the area with the greatest risk will be along and north of the I-10 corridor, especially over southwest MS and the adjacent LA parishes, however, can not rule out one or two potent storms south of that line.
- High confidence in locally heavy rain but where that actually occurs will be highly dependent on storm mode and location. The biggest concern is if storms do develop well ahead of the cold front, these will be more efficient and could train over the same areas, especially east of I-55 this evening and overnight.
Impacts:
The main threats associated with any severe storms will be:
- Damaging Winds: Wind gusts greater than 60 mph will be possible. Trees and power lines could be damaged and lead to isolated/scattered power outages
- Tornadoes: A few tornadoes will be possible. Timing and mode are key sticking points. Instability will be highest this afternoon but the shear will initially be rather low. However, shear is expected to increase this afternoon and more so early this evening. If the storms develop ahead of the cold front this afternoon and remain discrete, the tornado risk could increase from late afternoon through mid-evening. If storms hold off till the cold front things would transition more into a line of storms and then the tornado risk will be lower and the damaging wind threat will be greatest. If storms develop too far ahead of the front this would occur closer to midday and instability may not maximize. In addition, storms would likely become more numerous (multi-cellular) and storms would struggle to tap into the environment.
- Rainfall: In addition to the severe weather threat, rainfall of 1 to 3 inches is forecast with locally higher amounts possible. There is an increased concern for heavy rain east of I-55 late this afternoon and through the night. This rainfall could lead to ponding of water in low-lying areas and areas of poor drainage.
