The environment was highly sheared and exhibited moderate instability (~50 kts effective bulk shear; ~1600 J/kg MUCAPE). The NOAA/CIMSS ProbSevere model is designed to provide forecasters increased confidence and additional lead-time to the initial severe storm hazards. It does this by linking observed satellite growth and NWP environmental information with developing storms on radar. ProbSevere showed a strong normalized vertical growth rate at 2015 UTC, (see below) observed by GOES-East. The glaciation rate was 'weak', probably due to an overlapping cirrus canopy.
Because of the favorable environment and strong satellite growth rate, the probability of severe was 21% at 2036 UTC, while the MRMS MESH was 0.00 in. As MESH began to increase, the probability also increased (57% at 2046 UTC, 90% at 2050 UTC). The first 1.00" hail report was recorded at 2057 UTC in Bourbon Co., KS (11 min lead-time from ≥ 50%, 7 min lead-time from ≥ 90%). The first severe thunderstorm warning was issued at 2100 UTC.
A little later on and a little further south in far southeast KS, another storm exhibited exceptionally strong satellite growth rates (both normalized growth and glaciation rate) at 2045 UTC. While the MESH was about 0.2", the probability of severe was still 45-55%. A warning was issued at 2136 UTC, when the probability of severe was 52%. The probability eventually topped out at 60%, and 1.00" hail was reported in Jasper Co., MO at 2152 UTC.
The highest MESH in this storm was only 0.30 in. This is an example where observed satellite trends can help compensate for a weak radar signal (perhaps due to the low-precip, or LP nature of a storm), and how blending multiple meteorological data sources can increase confidence and lead-time.
This final animation just demonstrates the evolution of ProbSevere values for the line of storms, and their associated warnings.
John Cintineo
UW-CIMSS