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NWS CR Evaluation
Comments from Sullivan WFO
We did a high resolution run of the MM5 at the University of Wisconsin Milwaukee with Dr. Paul Roebber a few years ago for the June 1997 flood.
- There is an AMS article about this event. A copy is attached (see Section 3c. - Paul J. Roebber and John Eise. 2001: The 21 June 1997 Flood: Storm-Scale Simulations and Implications for Operational Forecasting. Weather and Forecasting: Vol. 16, No. 2, pp. 197–218.)
- We tried 1.67 and 5 km resolutions and found that there was no where near the convective detail/intensity at 5 km than at 1.67 km. Basically, we didn't even get the right convection in the right area at 5 km and would have missed any potential for flash flooding completely. The MM5 we ran was non-hydrostatic, did not use a convective parameterization scheme and used a two way nested scheme where the various resolutions "felt" each other.
I would love to see a short term high res grids in the first 24 hours down to 1.67 km and then run the rest at 5 km from that point on. Basically, higher resolution beyond 24 hours will only give us (in my humble opinion) a highly precise inaccurate solution.
In the end, EMC can turn off convective parameterization -- it is more a hindrance than help at 5 km -- especially with a non-hydrostatic model. Of course, 1.67 km would be best :-)