阅读下面这篇短文，短文后列出7个句子，请根据短文的内容对每个句子做出判断。 Weather and forecast Many of the
most damaging and life-threatening types of weather-torrential rains, severe
thunderstorm, and tornadoes-begin quickly, strike suddenly, and dissipate (消散)
rapidly, devastating (毁坏) small regions while leaving neighboring areas
untouched. One such event, a tornado, struck the north-eastern section of
Edmonton Alberta, in July 1987. Total damages from the tornado exceeded $250
million, the highest ever for any Canadian storm. Conventional computer models
of the atmosphere have limited value in predicting short-lived local storms like
the Edmonton tornado, because the available weather data are generally not
detailed enough to allow computers to discern the subtle atmospheric changes
that precede these storms. In most nations, for example, weather-balloon
observations are taken just once every twelve hours at locations typically
separated by hundreds of miles. With such limited data, conventional forecasting
models do a much better job predicting general weather conditions over large
regions than they do forecasting specific local events. Until
recently, the observation-intensive approach needed for accurate, very short
range forecasts, or "Nowcast", was not feasible. The cost of equipping and
operating many thousands of conventional weather stations was prohibitively
high, and the difficulties involved in rapidly collecting and processing the raw
weather data from such a network were insurmountable (不能克服的). Fortunately,
scientific and technological advances have overcome most of these problems.
Radar systems, automated weather instruments, and satellites are all capable of
making detailed, nearly continuous observations over large regions at a
relatively low cost. Communications satellites can transmit data around the
world cheaply and instantaneously, and modern computers can quickly compile and
analyze this large volume of weather information. Meteorologists and computer
scientists now work together to design computer programs and video equipment
capable of transforming raw weather data into words, symbols, and vivid graphic
displays that forecasters can interpret easily and quickly. As meteorologists
have begun using these new technologies in weather forecasting offices,
Nowcasting is becoming a reality. The author mentions the tornado in Edmonton, Canada, in order to give an example of a damaging storm.