November 1, 2013
Types Of Weather Forecasting
There are three types of forecasting we will look at in this post. The first is called short term forecasting. Short term forecasting is roughly from now until about five days in advance. This type of forecasting is accomplished by a combination of satellite imagery, radar imagery, upper air analysis, along with local area impacts, such as sea breeze, land breeze, anything that could impact just the local area. This type of forecasting also implements the use of weather models to examine what is taking place in the near future. Some parameters that are looked at for short term forecasting are the air temperatures, the wind speeds and direction, the cloud cover and any type of precipitation that may occur.
The second type of forecasting is the medium range forecasting. This can take a forecast out to about two weeks in advance. This is when we start to focus more on the use of weather models, jet stream flow patterns in the upper levels, along with up-stream weather patterns. For example, if there is an area of low pressure about five days upstream, this would be taken into consideration when making the longer term forecast as it could have implications on the weather forecast. This method also uses a lot of tendencies to forecast, such as what does this high pressure do when it moves into the area, or what does this low pressure do when it moves into the area. We also look at past weather events when making this range forecast. The final results are that we can now make a pretty good assumption of the weather out to about 15 days with the combination of all the methods mentioned above. This allows for a pretty accurate temperature range, along with precipitation totals and wind directions and speeds.
The third type of forecasting is long range forecasting. This can include anything over two weeks, and beyond one year sometimes. This method of forecasting is a bit more challenging as there are less day to day tools such as models, radar, satellite images to use when working with in this type of forecasting. One way to approach this type of forecasting is from weather patterns; certain weather patterns can give away longer term weather. A second approach is to use climatology for a given location. This allows a forecaster to see some standards of the area, such as what are my temperatures typically during this time of the year, how much precipitation does this place get during the month, due we see certain weather events more often than others during this month, are there certain wind patterns that setup during this month. Next, item that is used for long term forecasting are key elements in the atmosphere, along with the oceans. First of all we need to identify the solar cycle, where are we in the solar cycle, next week need to look at the ENSO phase, where do we stand a neutral period, El-Nino or La-Nina as each of these can have huge implications on the seasonal forecast. Then we must move into the oceans and how are they behaving; do we have blocking patterns setting up with our semi-permanent high pressures that could force weather systems to stall, accelerate or even take the same track time after time? All of these are things that have to be identified when looking at long term forecasting. Like I mentioned earlier, long term forecasting can play a lot on statistics as model guidance is very slim to none when you get to seasonal forecasting.
These are all things that we look at during different phases of forecasting.
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