The University of California, the Calif. Dept. of Water Resources, and the National Weather Service (NWS) have developed a new reference evapotranspiration (ETo) forecast tool with the NWS office in Sacramento. The ETo forecast is now online at http://www.wrh.noaa.gov/forecast/evap/FRET/FRET.php?wfo=sto. The map is quite impressive.

You can select the day of the week (starting with the current day), and it will show a color map indicating the ETo rates for that day. The forecast is for up to six days in addition to the current day (CIMIS only provides ETo up to the previous day). The NWS has also developed a useful product for growers to obtain weather trends. From the ETo map page, click on Forecast Weather Tables in the lefthand column. You can select hourly, 3-hourly, 6-hourly forecasts for several days in tabular format.

There is a lot of information there that growers want and use. The FRET values are really ETo. It stands for forecast ET.