West-WRF Ensemble Forecast Tools

The products are provided “as is” and are intended for research purposes only (disclaimer). All products on this page are considered experimental.

Santa Ana Index

The Santa Ana (SA) Index predicts the strength of a SA wind event, which is a downslope wind common to Southern California. The methodology was produced by a team from San Diego Gas & Electric Company, combining surface pressure gradient, 825-hPa wind speed, and 825-hPa cold air advection. The SA Index is calculated below using the West-WRF ensemble output along multiple transects over Southern California.

More information about plots

Select a coastal and inland location below to display the SA Index for that transect.

Coastal Location:  

Inland Location:  


Forecast Maps

Plot description: West-WRF Ensemble mean relative humidity shaded in percent and geopotential height contoured in decameters at 500 hPa (top row), 700 hPa, (second row), 850 hPa (third row), and 925 hPa (bottom row)

Variable 1:  

Variable 2:  

Plot description: Shading represents the probability of 12-hour accumulated precipitation to be greater than various thresholds from the West-WRF Ensemble forecast model. Probability is calculated based on the number of ensemble members predicting the variable over the chosen threshold.

Accumulation Period: