How effective are NWS tornado forecast products and are they improving in accuracy?
Please consult the latest Policy Statement by the American Meteorological Society. You might also want to consult my essay about the realities about tornadoes, mentioned just above. The effectiveness of NWS tornado forecast products depends on more than just the accuracy of the forecasts! As noted above, public education is an important factor in the reduction of casualties (and damage!) from tornadoes.