It looks like the NSSL WRF handled yesterday’s event pretty well. It represented the heavy rainfall in northern FL quite well, and the multiple “waves” of relatively disorganized-looking convection over northern AL. It was perhaps 1 squall line short of reality, and it also overdid the supercell potential in southern MS and AL, as this scenario did not materialize.
Some comparisons are shown below:
- The WRF reflectivity valid at 02z shows only 1 distinct squall line (1st image below) while the verifying radar shows 2 separate squall lines at 01z (2nd image). The 01z OBS is shown since the western squall line dissipated after 01z.
- The long-track supercell over southern MS and AL never materialized, as can be seen by the storm reports (3rd image).
- An experimental “Surrogate Severe” product is being worked on at NSSL (4th image). It combines severe values of many of the unique post-processed fields that Scott Dembek of SPoRT helped implement into the NSSL WRF (max hourly updraft helicity, 10-m wind speed, updraft/downdraft strength, and graupel density). The smoothed product correlates fairly well with the severe reports yesterday. These plots are available daily for the full-domain view of the NSSL WRF output by scrolling all the way down on the left-hand side.