Some of the details assigned by Grazulis for post-1950 tornadoes differ from those in the official SPC database, including the F-scale ratings of about 2200 tornadoes. This isn’t too surprising ...

The forecasts issued by the SPC are used and viewed by millions ... Marsh said days like the Moore 2013 tornado are days that ...

the first tornado classified as 'EF-5'. The EF scale was adopted on February 1, 2007. The Storm Prediction Center has a brief description of the Enhanced Fujita Scale. EF-0 (65-85 mph) F0 (65-73 ...

The SPC further defines significant severe thunderstorms as any storm that produce one or more of the following elements: A tornado produces EF2 or greater damage. Wind speeds of 75 mph (65 knots ...

While details about the budding threat are still being sorted out, the SPC warned that strong tornadoes, large hail and damaging winds are all on the table for Saturday. Residents are being asked ...