Convection in the Hoosier state

During day 2 of the HWT this week, the forecasters are tracking a line of storms heading through Michigan. Further south, however, storms fired along the cold front prior to our shift (~11:00am on May 13) in Indiana. In figure 1, we see part of the line with an elevated probability of severe (from the NOAA/CIMSS ProbSevere model). A strong satellite normalized vertical growth rate and moderate glaciation rate contributed to probabilities in the 45-55% range. The environment was marginal, and the MRMS MESH started to increase in the 0.6-0.7" range. When the NWS issued a severe thunderstorm warning, the MESH spiked to 1.84" and the probability increased to 96%. This storm later produced wind damage in northern Indiana.

Figure 1: Early convection over northern Indiana.

Further south, more storms developed on or ahead of the cold front. You can see that for the featured storm in eastern Indiana (figure 2), the strong satellite growth rates jumped the ProbSevere probability from 4% to 51%. MESH was only around 0.3". The NWS did issue a warning on this storm at 2:30pm (figure 3), 16 minutes after the first probability of over 50%. No reports have been recorded yet.

Figure 2: Convection in eastern IN. Satellite growth rates contribute to elevated probability of severe prior to NWS warning. MESH was very marginal.

Figure 3: NWS warning that came out at 2:30 PM.

-Cintineo/Sieglaff