Prob Severe over 90%…our warnings cover it!
Pardon my puns. Mr Snow and I were testing out the NUCAPS product now that things have settled down in our DMA. We selected different locations and got different results.
Compared to surface obs, the NUCAPS temperature did not need to be altered, but the moisture did, by about 6 degrees Celsius. This change took my MU parcel cape from 15J/kg to ~2000J/kg. SPC meso had it closer to 1500J/kg. The EL also doubled from 6 to 12 km.
We did have storms just SW of this area, however, as they lifted NE, they weakened.
Checked NUCAPS sounding at 19Z just east of LBF and used T/Td of 89/66 to modify the surface and got around 4000 J/kg CAPE. Initially NUCAPS near the surface was much too cool and dry (80/54), so the modification was necessary. It did agree better with the SPC mesoanalysis and RAP which showed values over 3000 J/kg and much better than the LAP CAPE. MrSnow/BT
We held off on issuing a warning for a cell moving into our CWA from Dawson County to the south where it produced 3″ diameter hail at 2305 UTC. For 3 reasons we held off.
1. the near storm environment had already been worked over by previous storms and radar showed stratiform rain falling in our area.
2. Prob Severe dropped from 96% at 2316 UTC to 41% at 2326 to 5% at 2330.
3. Lightning was not very impressive and diminished to near zero in the time series plot.
A rapidly growing storm developed over Putnam county IL and is slowly shifting eastward into La Salle county IL. The lightning jump algorithm has indicated as much as a 5 sigma increase with this storm. The CIMSS Prob Severe Model has indicated a high probability of severe storms over Putman and La Salle County. See images of below, including the the severe thunderstorm warning issued for La Salle County.