After an initial batch of rain and embedded storms that are continuing to move across the easernt half of the LMK forecast area, there is a narrow corridor of partial clearing, behind which another band of convection is forming. It is somewhat apparent in the PHS fields (both CAPE and STP) that there is better destabilization across western portions of the CWA under partial clearing.
Top left: PHS modeled CAPE at 20z. Top right: PHS moceled STP. Bottom left: GOES CAPE 20Z. Bottom right: GOES LI 20Z.
By 20Z, had issued a significant weather advisory for a cell in the northwestern and portion of the forecast area. ProbSevere began spiking, and GLM FED picked up while MFW decreased, indicating strengthening updrafts. Within the next 20 minutes, cells in the southeastern forecast area began exhibiting similar behavior, and I issued another advisory for those.
0.5 degree base reflectivity at 20Z overlaid with probSevere
4 panel GLM over IR at 20Z
ProbSevere was indicating more of a wind threat, and a secondary threat from hail with MESH up to a half an inch. Why did I not go severe? Base velocity was decent, up to 30kts on the 0.5deg tilt. Base reflectivity up to 50dbz was only apparent up through around 18kft. NUCAPS soundings from earlier in the day, courtesy of metop C, indicated a freezing level around 11kft, so I would believe small hail.
Mid morning NUCAPS sounding over central
By 2130Z, lingering activity is pretty much stratiform with just some embedded storms. Examining Day Cloud Phase Distinction (DCPD), and instability fields courtesy of PHS, we might figure out why. DCPD is indicating thick cloud cover over much of the eastern two thirds of the CWA. Meanwhile, CAPE and STP remain maximized closer to the western CWA boundary, under the area of clearing skies.
21Z DCPD
PHS 21Z modeled CAPE, STP (top) and GOES CAPE, LI (bottom)
19Z NUCAPS soundings (from the NOAA20 overpass) were largely unavailable over the CWA due to cloud cover.
A Modified NUCAPS sounding out of SW KY indicates quite a bit of dry air at the midlevels, but also decent lapse rates and as much as 1500 to 2000j/kg of CAPE
For comparison, the regular, non-modified NUCAP profile at the same location was far less bullish with the instability.
A look at base reflectivity at 2130 indicates that trend towards mainly stratiform rain with embedded storms. In the eastern CWA, ProbSevere is still pretty enthusiastic about an exiting line of convection with probability ranging as high as 20 to 30% for wind and even up to 20% for tornadoes. An examination of base velocity did indicate some inflow notches ahead of the line.
Base reflectivity with probSevere around 2130Z
However, with GLM FED remaining steady, and MFA on the larger side, the confidence in any real severe weather is waning.
– PoppyTheSmooch