SPC storm ingredients: feeds current
SPC storm ingredients: Feed current; checked .
Checked means retrieved, not newly issued. Each graphic retains its issue, observation, initialization or valid time. Site publishing status is separate.
Storm ingredients: SPC’s hourly analysis
Tornado index: Significant tornado parameter (effective layer) (no units)
An index SPC combines from instability, cloud-base height, shear and low-level spin. Above 1 the environment has looked like those of strong tornadoes. It is not a tornado forecast and says nothing where storms do not form.
The technical reading
Effective-layer STP, with CIN: (MLCAPE / 1500 J/kg) × ((2000 − MLLCL) / 1000 m) × (effective SRH / 150 m²/s²) × (effective bulk shear / 20 m/s) × ((200 + MLCIN) / 150 J/kg), with SPC’s limits, dimensionless. Most significant tornadoes have occurred with values above 1 in an environment with supercells.
An ingredient, not a forecast: SPC’s analysis of the hour, from observations and a short-range model’s first guess. No one value is a warning or an outcome; storms need several ingredients together, and something to start them.
SPC mesoanalysis checked · Data: NOAA/SPC
Not an official warning service. Warnings and watches are the National Weather Service’s, outlooks and reports the Storm Prediction Center’s and the Weather Prediction Center’s (Data: NOAA/NWS, NOAA/SPC, NOAA/WPC). When a warning is issued for you, act on it, and use weather.gov or a NOAA Weather Radio for where you are.