Warn on Forecast

MRMS display

Warn-on-Forecast is a National Oceanic and Atmospheric Administration (NOAA) research program tasked to increase tornado, severe thunderstorm, and flash flood warning lead times. Increasing the lead time and accuracy for hazardous weather and water warnings and forecasts, in order to reduce loss of life, injury, and damage to the economy, is one of the strategic goals of NOAA. Trends in yearly-averaged tornado warning lead time suggest that the present weather warning process, largely based upon a warn-on-detection approach using National Weather Service (NWS) Doppler radars, is reaching a plateau and further increases in lead time will be difficult to obtain. A new approach is needed to extend warning lead time in which probabilistic hazard guidance is provided by an ensemble of forecasts from convection-resolving numerical weather prediction models.

NEW! The 2014 Warn-on-Forecast and High Impact Weather Workshop will be held at the National Weather Center Apr. 1–3. Download the agenda (.pdf, 89 kB) (updated 27 Mar 2014)

Warn-on-Forecast Project Plan (.pdf, 245 kB)

Warn-on-Forecast Fact Sheet, a brief overview of the WoF project, in layperson's language (.pdf, 878 kB)

Damage from May 3 OK tornado

Left: An ensemble of storm-scale NWP models predicts the path of a potentially tornadic supercell during the next hour. The ensemble is used to create probabilistic tornado guidance.

Right: Probabilistic tornado guidance: Forecast look on track, storm circulation (hook echo) is tracking along centerline of highest tornadic probabilities. [+]

Left: An ensemble of storm-scale NWP models predicts the path of a potentially tornadic supercell during the next hour. The ensemble is used to create probabilistic tornado guidance.

Right: Probabilistic tornado guidance: Forecast look on track, storm circulation (hook echo) is tracking along centerline of highest tornadic probabilities.