How are the “point-and-click” forecasts created?
Each NWS forecast office creates and edits graphical forecasts for their area on a 2.5 x 2.5 km grid, with each grid box being assigned a unique value for each forecast element. (In the case of the Salt Lake City forecast area, this equates to more than 30,000 grid points.) These grids are created for many forecast elements, with the general public most frequently using elements such as temperature, wind direction and speed, probability of precipitation (POP), etc. When you click on our maps to get the forecast for your specific neighborhood, the program pulls the forecast from that particular grid box, and then decodes those values into a text forecast. An example of one of these graphical forecasts can be seen below. Forecasters have a wide variety of tools for editing these grids, such as the ability to only edit certain areas at a time, tweak values at individual cities, copy in and edit grids directly from computer models, or nudge the forecast toward a particular computer model.
