Utilitly of Prob Severe Combined with Sat Growth Rate and Lightning Flash Rate in Predicting Severe Weather

As storms continue to fire along the dry line in the OUN forecast area, we continue to find utility with the CI and Prob Severe algorithms determining where severe weather is likely. The CI algorithm jumped to 98% at 20Z with with the Severe CI 66% in Stephens County.  They supercell would be the precursor for the Garvin County tornado.

This storm entering Garvin County showed a sharp increase in Prob Severe from 45% at around 20:30Z to 95-100% within 10 minutes. The satellite growth rate was high, and lightning flash rate jumped from minimal to around 50 flashes/minute during this period. The LTG Jump increased from nothing 26 standard deviations above normal at 2035Z about a half an hour before the tornadol

We issued a severe thunderstorm warning based on this information and radar imagery. Within the next half hour, this cell produced a tornado on the ground.

Update 1: This turned out to be a long lived and very strong tornado in Garvin County. 

Update 2: The supercell kept going, and the mesocyclone became broarder.  A decision was made to expand the tornado warning further downstream at 2133Z. It worked out well.

  The hook echo is seen in the reflectivity image.

   At this point the tornadic couplet was well-defined in the polygon.

At 2154Z, another tornado was on the ground with 86 kts of gate to gate rotation with a shear value of 0.0843 s-1.

Reverting back to the CI and Severe-CI products. 

The CI-product peaked at 93% and the SVR-CI 57% at 22Z further depicting the long-lived track of this severe supercell that kept producing tornadoes.


- JP/Yodamaster777