ProbSevere v3 improving upon v2 in Indiana and Illinois

ProbSevere v3 (PSv3) was providing improved guidance to HWT forecasters in Northern Indiana yesterday, compared to ProbSevere v2 (PSv2). Along and south of a warm front, PSv3 was consistently 20-30% higher, with ProbWind showing the highest threat. The shear and CAPE were marginal in this environment, and the lightning and radar-reflectivity parameters were meager in most of the storms. However, the low-level wind field (evident in ProbSevere's 1-3 km AGL MeanWind predictor) was quite favorable for a severe wind threat (30 - 40 kt).

Below are several sampled storms in AWIPS showing much higher PSv3 values, compared to PSv2. Each of these storms went on to produce one or more severe wind reports. A post-mortem analysis of each storm revealed that the 1-3 km MeanWind, the 0-3 km lapse rate, and the STP (effective layer) were among the most important predictors for these storms. The normalized satellite growth rate was also a strong contributor, as well as the ENI lighting density, in several stronger storms. 

Convective initiation in the Hoosier State

One of the teams at HWT today is working in Northern Indiana. There is a tornado threat later, and the team is also working a DSS situation at a Fort Wayne baseball game. LightningCast is hitting on convective initiation in Kentucky and southern Indiana.

Figure 1: LightingCast contours, GOES-16 GLM flash-extent density, and GOES-16 ABI day cloud convection RBM over Indiana and Kentucky.