Friday, April 19, 2013

Verification continued

Yesterday I showed the full period (roughly a day 1 convective outlook) of the SSEO. Since we will test the ensemble at finer time scales, down to 3 hour periods, here are the three 3hr periods under consideration.
18-21 UTC
The figures presented here should be used with caution. The models do not always produce reliable or skillful forecasts of the initiation or evolution of convection or convective mode. Thus using them as I did before depends crucially on being good enough in the time period under consideration to provide useful but not specific guidance.

This first thing you may notice is how circular all the probabilities look due to the use of a gaussian smoother. Thus there are both very few reports and model simulated reports in these areas. There is very little overlap between reports and model reports.
21-00 UTC
In this second period, model reports increase dramatically for some members. The amount of overlap increases for NSSL-WRF, NMMB, and 3/4 of the HRW members. Not bad. I would hope that the members can capture some of the severe weather scenario that played out, including getting close to the proper location. NSSL-WRF does well in this period in SW OK as do the HRW-NMMs. If you look to NE MO then those members plus an HRW-ARW member cover that maximum pretty closely.
00-03 UTC
In the 3rd period, the ARW's, NSSL-WRF, and NMMB and HRW-NMM all contribute (glancing blow for some of them) in some way to the maxima in SW OK. The same holds for MO.

For this case at least, the models appear to be able to simulate at least 3 hour probabilities of total severe weather. As I have indicated elsewhere, the use of UH to match against all severe reports appears, again for this case, justified. Such will be one of my foci for the upcoming Hazardous Weather Testbed Spring Forecasting Experiment as part of the Experimental Forecast Program. Testing this out for a bunch of cases this year, and extending it back in time will be a goal of mine moving forward.