Severe Weather Outbreak Potential for Southern United States
Issued April 12 2020 – 1:00 PM
FORECAST DISCUSSION:
There continues to be a very real possibility of a serious severe weather outbreak across the southern United States this afternoon.
Presently there is a complex of severe thunderstorms moving through north central Louisiana and tornadoes have been reported east of Shreveport, LA. This complex of thunderstorms will continue pressing toward the northeast into SW AR and western MS. There is also a line of storms, with radar indicated rotation, moving through north central MS. These are along and just north of a warm frontal boundary. The air mass south of this warm frontal boundary is warm and very humid. Dew points are in the upper 60’s and lower 70’s throughout this area and will provide fuel for the continuing development of thunderstorms throughout the afternoon.
Later this afternoon a new line of thunderstorms looks likely to form during the time of maximum heating of the atmosphere in the warm and humid air mass south of the warm front.
This line of storms will move through Mississippi and then into north central Arkansas by late evening. There will be the substantial risk of strong winds, hail and tornado activity. Given the environment that these storms have to work with the potential for widespread tornado activity is very high.
As we discussed yesterday, one measure of determining the likelihood of tornado activity is the Energy-Helicity index. Values of 1 or more indicate a strong potential for tornadoes. Some values in the chart above are in excess of 7 which indicates a strong potential for very large severe tornado development. Residents of LA, MS, AR should be prepared for the possibility of life threatening weather.
This situation has prompted the Storm Prediction Center to issue a Particularly Dangerous Situation alert along with the Tornado Watches which have been issued this afternoon.
Further information about this Tornado Watch/PDS can been obtained at:
https://www.spc.noaa.gov/products/watch/ww0106.html
This situation will continue to evolve this afternoon and I will issue further updates as conditions warrant.
Bay State Weather 