Severe warning lead-time in Brownsville WFO

While thunderstorms are remaining well below severe thresholds over the Middle Missippi Valley, a strong to severe thunderstorm initatied in the Brownsville WFO along residual outflow Thursday afternoon.  Figure 1 shows ProbSevere contours along with GOES visible imagery and MRMS composite reflectivity from the ProbSevere website zoomed on the storm in the Brownsville CWA.  The storm was in a favorable environment and exhibited strong satellite growth rates and glaciation rates, with a beginning probability of 28% at 1936 UTC.  The probability quickly increased (exceeding 80% at 1952 UTC) as lightning flash rate and MRMS MESH increased through 2014 UTC, when the first severe thunderstorm warning was issued.  This illustrates how ProbSevere can extend lead-time and increase confidence.

-Sieglaff