Forecaster notes strong ProbSevere in Arkansas

With the Little Rock radar down all afternoon, a forecaster working the warning desk in Shreveport, LA, noted a strong ProbSevere value on a storm in central Arkansas. This storm exhibited strong satellite vertical growth and glaciation rates at 22:45 UTC, jumping the probability of severe from 8% to 36% (see animation below). In a marginal environment, the MESH slowly increased to 0.76", most likely an underestimate, on account of the missing KLZK radar data.

The forecaster said that using the strong satellite growth rates and MESH information from ProbSevere, the available radar tilt data from KSHV and KSRX, and the history of how other storms have evolved in this environment, he would have issued a severe thunderstorm warning for quarter-size hail (he was on the warning desk in Shreveport, so he could not issue an experimental warning).

The ProbSevere probability for this storm first exceeded 40% at 23:00 UTC, which has been very high for the environment today. This was 24 minutes prior to an official NWS warning at 23:24 UTC (figure 2). The ProbSevere eventually exceeded 80%.

Figure 2: NWS warning issued at 23:24 UTC.

-Cintineo