More Severe Storms and some ProbSevere False Alarms

More storms continue to fire along and ahead of the dryline over north central Texas and western Oklahoma Wednesday afternoon.  Another storm became severe warned over Baylor and Archer counties in Texas at 2123 UTC (Figure 1).  The NOAA/CIMSS ProbSevere model had high probabilities (> 70%) on this storm for nearly an hour prior to the warning being issued.  The first severe report with this storm was 1.75" (golf ball) hail at 2130 UTC 7 May 2014 in Westover, TX.

Figure 1.  NOAA/CIMSS ProbSevere and MRMS composite reflectivity at 2118 UTC 7 May 2014--notice the latest warnings features a storm with very high ProbSevere values and had high values for nearly an hour preceding the warning.

Further north, many storms over Oklahoma have had high ProbSevere values but have yet to receive severe thunderstorm warnings nor severe reports, contributing the false alarm counts (Figure 2).  These storms have favorable environmental conditions and have exhibited strong satellite growth rates--along with MRMS MESH values around 1.00"--which explains high probabilities.  Discussions with EWP forecasters are ongoing on why these storms do not seem to be producing severe weather.

Figure 2.  NOAA/CIMSS ProbSevere and MRMS composite reflectivity at 2100 UTC 7 May 2014.  Notice many storms over Oklahoma with high ProbSevere values (white and pink contours)--as of this writing these remain as false alarms as no severe reports have been received with these storms.

-Sieglaff