Weather statistics help meteorologists to produce futuristic forecasts for an extended period of time. One trend discovered by forecasters is that 'normal' weather conditions may be an infrequent aspect of Mother Nature. What this means is that normal weather conditions encompass a wider variable then one single common form. For instance, the majority of this year has produced above normal temperatures and below normal precipitation. These abnormalities seem significant to many, but in reality, they are quite typical.
Area meteorologists continuously refer to daily temperatures and precipitation levels as either being above or below normal. The climatic normal is a useful means to describe the average weather conditions for a localized region such as North Conway. This atmospheric information is an accumulation of thirty to one hundred years of recorded data. Meteorologists obtain average weather conditions through arithmetic procedures that include basic and complex equations.
Though mathematical equations produce accurate statistical information, the procedures may not represent normal weather conditions in true fashion. Take for instance New England's most active atmospheric period of time, which is the winter season. During the decade era of 1990 to 1999, New England witnessed seesaw winter precipitation levels. The year 1994 was very dry with snowfall well below average, while 1995 produced one of the snowiest winter seasons on record. It is interesting to note that throughout the decade there were no winter seasons that produced average conditions. This may make you wonder about the relevance of the term 'normal.'
A person who is unfamiliar with climatology (the study of the climate) may perceive normal to be weather conditions that are expected to occur every day. However, it is important to realize that the climatic normal may, or may not, be weather conditions that are going to occur. For example, areas such as the American Southwest and the Northeastern United States frequently experience large trends in atmospheric conditions. Therefore the meteorological normal for precipitation and temperatures are least likely to occur.
You may wonder why meteorologists continue to refer to daily, monthly and yearly weather conditions as being above or below normal. This information is provided because the climatic normal represents long-term features of precipitation and temperature. The results are utilized to better plan for the future. For example, when a region receives below normal precipitation for a lengthily period of time, such as the current dry spell in the Valley, residents are able to understand the significance of the condition and take appropriate action.