All,
First I want to apologize for no further traffic on this thread.
A quick overview on the current PotThunder population in ForecastBuilder. It uses a blend of MOSGuide, SPC SREF Calibrated Thunderstorm Probabilities and GLAMP Calibrated Thunderstorm Probabilities (whenever each are available). Bringing in these methods provide a level of science and statistics that was never there before. The previous method is still available, under the Edit menu -> PoT_Thunder.
A lot of people, including myself, have been looking into the probability of thunder conundrum. SPC has done some research on the SREF Calibrated Thunderstorm Probabilities, which go into the PotThunder calculation now, and have found that they are very reliable when looking at the observance of 1 lightning strike within a 40 km grid. However, because they are calibrated, they will come in lower than what we are use to. On the flip side, without pure scientific research but going along the research that was done for aviation verification, I feel pretty confident the setting the probability of thunder to the PoP was too high. So some balance is needed here, and I think that was borne out from Ken's findings.
At ARX, we are experimenting with a modification to the Wx creation where if the PotThunder is within 20% of the PoP, the PotThunder is given the PoP "verbiage." On an aside, this could help simplify some of the mixed precipitation scenarios. 20% can help separate out those events where we would see thunder from any shower, and those where we should have lower thunder probabilities. Additionally, through the experimentation we found cases where you only want Isolated/Schc, so a hook has been thrown in to keep any PotThunder values <= 20 as Isolated.
