This 10 part series will detail forecasting tricks that can be used to try to outforecast MOS. Outforecasting MOS is an important skill for a forecaster. MOS stands for Model Output Statistics and they are used as a guide for temperature prediction and precipitation prediction by forecasters. Model consensus is the average of the high temperatures, low temperatures or precipitation amount predicted by several forecast models. PART 8: TIMING PRECIPITATION The timing of precipitation is an important component of precipitation prediction. Not only is it important to know how likely precipitation is, it is important to know when it is most likely to occur. Here are several techniques to time a precipitation event: 1. If it is a line or area of storms that have already developed then put the image into motion on radar and note how far the precipitation area moves over a given time. Using that same rate of movement determine when the precipitation will enter the forecast area. Look at the models to see if the forcing mechanism for the precipitation is slowing down or speeding up. Adjust the timing using this information. 2. Determine the forecast model consensus for when the precipitation event will occur. If several models agree while a lone model does not, odds are the lone model will be wrong. 3. Storms in a particular forecast area will tend to develop at a certain time of the day. Mountain convection and sea breeze convection will often occur at a similar time each day. Keep of journal of when convection occurs each day. 4. The best precipitation threat often occurs just before a front moves through. Time the frontal passage on the models. The best precipitation threat will be around this time. 5. Time the ending of a precipitation event by noting when the back edge of a precipitation region should enter the area and when dynamic lifting becomes dynamic sinking on the models. |