Features/Forecast-Modeling.md

@@ -5,6 +5,7 @@ title: Forecast Modeling
 
 
 
+
 # 📅 Forecast Modeling
 
 Forecasts in Backbone allow you to represent future uncertainty in optimization by supplying multiple possible forecast paths (realized, central, optimistic, pessimistic, etc.) for the same time series.
@@ -139,14 +140,29 @@ Here, reservoir inflow is smoothed over a 168-hour (weekly) window between the e
 
 > 👓 See [Time Series Circulation](../Features/Time-Series-Circulation) for a full list of available rules and parameters.
 
-
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-## 🚧 Practical Modeling Tips
+## :crystal_ball: Nonanticipativity
+
+Nonanticipativity prevents the model from “peeking” into different forecast branches at the very start of each solve.  
+It forces early decisions (unit commitment, storage use, transfers) to be the same across all non-realized branches.
+
+### Why it matters
+Without this, the model might exploit branch-specific futures immediately (e.g. charging storage in one forecast, discharging in another), which is unrealistic.  
+Nonanticipativity keeps the first hours **robust and consistent**, avoiding artefacts.
+
+### How it works
+- Applies only when **multiple forecasts** are active.  
+- Locks early timesteps `t_nonanticipativity` so that:  
+  - **Unit online status** (`v_online`) is equal across branches.  
+  - **Node balances** (sum of generation, transfers, spillage) are equal across branches.  
+- Realized and central forecasts remain free; other branches must match the central forecast.
+
+### How to use
+- Set [mSettings('nonanticipativity')](../Features/Dictionary#forecast-timing-and-update-settings) = X → applies to the first *X hours* of each solve (0 = off).  
+- If only one forecast is active, the option has no effect.  
 
-- Clearly differentiate between realized (`f00`) and central (`f01`) forecasts.
-- Ensure forecast probabilities logically sum (excluding the realized forecast).
-- Adjust forecast timing parameters according to model granularity and forecasting practices.
+:link: See also [Schedule Simulation](https://gitlab.vtt.fi/backbone/backbone/-/wikis/Features/Schedule-Simulation#2-key-time-parameters)
 
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