Technology
What is Instacast?
Previsico's 24-hour lookback shows where flooding has likely already occurred, built from observed rainfall rather than a forecast, so responders know what's happening now, not just what might happen next.
What is Instacast?
Instacast is Previsico's 24-hour lookback feature. It uses the most recent hour of observed radar rainfall to update our hydrodynamic model, showing where flooding has likely already occurred at property-level detail. It bridges what has already happened and what may happen next, giving responders immediate situational awareness as a storm unfolds.
Observed, not forecast
How Instacast works
Built on observed rainfall
Uses the most recent hour of radar-observed rainfall, not a weather forecast.
24-hour lookback
Models the full preceding 24 hours so teams can track how conditions evolved through a storm.
Same property-level detail
Uses the same spatial resolution as Previsico's probabilistic forecast for a consistent picture.
Deterministic, not probabilistic
A single modelled map of what has likely already happened, not a likelihood band.
Instacast vs. the 48-hour forecast
Previsico's probabilistic forecast looks forward, reporting a likelihood and severity band for the next 48 hours. Instacast looks backward, using real observed rainfall to show what has likely already flooded in the last 24 hours.
Used together, they bridge "what has already happened" and "what may happen next", giving responders a single continuous picture through a storm rather than two disconnected signals.
Frequently asked questions
Instacast is Previsico's 24-hour lookback feature. It uses the most recent hour of observed radar rainfall to update our hydrodynamic model, showing where flooding has likely already occurred at property-level detail. It bridges what has already happened and what may happen next, giving responders immediate situational awareness as a storm unfolds.
No. Instacast is deterministic, not a forecast: it models what has likely already happened from observed radar rainfall over the last hour, rather than predicting what might happen next. See probabilistic flood forecasting for Previsico's forward-looking, 48-hour forecast.
Up to 24 hours. Instacast updates hourly, using the most recent observed rainfall to show how conditions have evolved through a storm.
They're complementary. Instacast shows what has likely already flooded, using observed rainfall; the probabilistic forecast shows what may flood next, using forecast rainfall. Together they give continuous situational awareness through a storm, from Explore the Flood Intel Platform to see how they sit together in the dashboard.
See Instacast on your own sites.
Get a free flood-risk assessment and see how the 24-hour lookback works for your assets.
Related reading: Probabilistic flood forecasting · Explore the Flood Intel Platform · More answers