Here’s my summary of yesterday’s (Monday’s) activity at the HWT.

This is a very quiet week for mid-May.

The DTC has been well-received. I presented Jamie’s verification .ppt and gave it away to several interested people. The need for objective verification is great. There so many models and little time to analyze everything after the fact. Mike Coniglio led two discussions of Friday’s MODE verification output. The CAPS model without radar data assimilation lagged behind the CAPS model with radar data assimilation. MMI was similar for the two models, but the MODE centroid distance was a distinguishing factor. The model that lagged behind had greater centroid distance. This wouldn’t have been possible to quantify with conventional verification metrics.

We also subjectively evalutated the Friday storms over the centeral U.S. The 0Z NMM had a false alarm storm in the morning that disrupted the afternoon forecast. The simulated squall line was much weaker than the observation. This was not as much of a problem with the NSSL model. The 12Z NMM was not a whole lot better with convective mode and individual storm evolution, but its 0-2 h and 6-12 h forecasts had better storm placement than the older 0Z NMM.

As an aside, ARW runs with Thompson microphysics have less intense simulated radar reflectivity than observed.

For Monday afternoon and evening’s severe weather forecast, we chose Billings, MT as the center point. It was the only place to have the possibility of severe weather. We broke up into 2 teams and came up with a less than 5% chance. Two actual reports were northwest of our predicted zone in northern Idaho. Radar indicated some small storms in our predicted zone.

Dave Ahijevych