Here is an update concerning the heavy rain and severe weather threat through tonight.
Key Takeaways:
- We continue to be concerned with the threat of localized higher-end rainfall totals, and the threat now looks like it will extend through the overnight hours for much of the area. As a result, the flood watch has been extended area-wide through 7am Sunday.
- There is potential for slow-moving or stationary storms capable of producing rainfall rates in excess of 2 inches per hour. These high rainfall rates can quickly lead to street flooding and ponding of water in low lying and poor drainage areas.
- The likelihood of localized totals approaching or exceeding 5-7 inches SOMEWHERE across the area continues to increase and we cannot rule out a few totals of as high as 10 inches. IF these higher totals affect more urbanized areas, drainage capacity would be overwhelmed, leading to significant impacts such as widespread street flooding with numerous roads becoming impassable due to high water, or even some buildings becoming flooded.
Overview:
WHAT: SLIGHT to MODERATE RISK (level 2-3 of 4) of Heavy Rain that could lead to flash flooding; MARGINAL RISK (level 1 of 5) of severe weather
WHEN: This afternoon through tonight
WHERE: All of southeastern Louisiana and southern Mississippi
CONFIDENCE:
- We are confident that showers and thunderstorms will become more numerous this afternoon and into the evening and are already seeing some development across areas near the Atchafalaya River
- We are confident that some storms this afternoon will become stationary or near-stationary, which could result in localized rainfall totals of 5-7″ or more, but have little confidence in the specific areas that will receive the heaviest rain
- We have medium confidence that a few storms could become severe this afternoon
Impacts:
The main threats today through tonight will be:
- High rainfall rates in excess of 2″ per hour could lead to localized rainfall totals upwards of 5-7″. A few totals of up to 10″ cannot be ruled out
- These high rainfall rates and totals will quickly lead to ponding of water in low lying areas and areas of poor drainage, especially if the heavy rain falls over urbanized areas
- Street flooding is likely from some storms, and several roads may become impassable in areas that receive the most rain
IF any storms become severe, the main threats from those storms will be:
- Damaging wind gusts greater than 60 mph which could cause damage to trees and power lines, leading to isolated/scattered power outages
- One or two tornadoes
