Severe Threat–Saturday 3/23/13
Here is the current surface setup this morning. We currently have a weak area of low pressure centered over Central Texas around the Dallas metro area with a warm front extending across the northern Gulf Coastal plain and Black Belt areas. The movement of this warm front will be vital in just how unstable portions of the deep south get on this afternoon and Saturday when it comes to the potential for severe weather. A rather deep upper trough to the east will keep cool advection coming in pretty strong to the north of the warm front, but a deepening wave to the west should turn winds more southerly and at least get the surface features moving northward somewhat in response. These are all questions that will become resolved in the next 24 hours.
The day 2 convective outlook from the SPC highlights a good chunk of Alabama in a SLGT risk (standard risk) of severe storms for Saturday afternoon and into the overnight.
A 30% risk area has been defined from areas encircled from a Monroe, LA – Dothan, AL – Tuscaloosa, AL – Jackson, MS region. This area is expected to see the most unstable air mass during this period and will likely be in the uncontaminated warm sector for a decent period of time. Thus, diabatic heating could allow temperatures to soar into the mid 70’s to lower 80’s. This will need to be monitored for a possible upgrade to moderate risk if these factors do indeed come together.
At this time, we look for scattered cellular development to take place across Mississippi and Alabama tomorrow afternoon with the threat of hail, high winds, and a tornado or two. The hail threat could be rather significant. Then, the instability axis is forecast to spread northward toward the Tennessee Valley ahead of the cold front and allow for a strengthening line of severe storms to push through much of Central Alabama. We will continue to keep you alert of changes with the situation through early tomorrow. Stay tuned as we will likely have teams in the field for this potential high impact weather event.
