Storms over western Iowa

Strong thunderstorms have developed along and ahead of the dryline over far eastern Nebraska and have moved into western Iowa.  Figure 1 shows the evolution of these storms--notice the ProbSevere values fluctuate--occasionally into the higher ranges (pinks > 70%).  These storms are in a favorable environment, have exhibited strong satellite growth rates, and have cycled in radar-estimated intensity.

Figure 1. NOAA/CIMSS ProbSevere and MRMS composite reflectivity valid 2014 - 2112 UTC 8 May 2014.

A question was posed to the pair of forecasters working the DMX WFO at the EWP:

"These storms have exhibited some high probabilities and have fluctuated as the radar intensity ebbs and flows.  How would you use the storms in these in this scenario and what would you suggest as data inputs into ProbSevere to improve the statistical model?"

"One forecaster replied, I like the fact that probabilities are fluctuating with radar intensity, it tells me the storms are cycling and may not be steady-state ready to produce severe weather.  Another forecaster said it would make it more difficult to use--but combined with analysis of radar tilts and the velocity data--it still tells me what storms are going to pose the highest threat.  We've seen storms that get high probabilities and don't cycle--they produce severe weather--but not these.  So that's the million dollar question.  Both added additional pieces of information that might add value would be melting depth (freezing height) (although they noted not in this case) as well as additional reflectivity information at higher levels."

This type of interaction does NOT occur when researchers are in their institutes and forecasters working a shift in their WFO.  It is experiments like these that facilitate the most rapid improvement in new products and the prospect of 3 more weeks of interactions is exciting.


-Sieglaff