METR121 Ch 9

A weather warning indicates that hazardous weather is either imminent or actually occurring within the specified forecast area.

true

Because the many weather variables are constantly changing, meteorologists have devised atmospheric models that describe the present state of the atmosphere.

true

Even with better observing techniques and near perfect computer models, there are countless small, unpredictable atmospheric fluctuations that fall under the heading of chaos.

true

Predicting the weather by weather types employs the analogue method: weather patterns are categorized into similar groups or "types," using such criteria as the position of the subtropical highs, the upper-level flow, and the prevailing storm track.

true

Currently, forecast models predict the weather reasonably well days ________ into the future.

4 to 6

The National Weather Service communication system in use today is known as ________.

AWIPS

What dominant influence in the field of weather forecasting for 2000 years consists of examining natural signs, such as the color and shape of clouds, and the intensity at which a fly bites?

Book of Signs

________ tend to move in a direction that parallels the isobars in the warm air ahead of the cold front.

Low pressure areas

The ________ method relies on the fact that existing features on a weather chart (or a series of charts) may strongly resemble features that produced certain weather conditions sometime in the past.

analogue

What type of forecast is based on the climate of a particular region?

climatological forecast

A medium-range forecast is one that extends from about 8 to 10 days into the future.

false

A preliminary (rough draft) forecast chart representing the atmosphere at a specified future time is called a prognostic chart, or, simply, a prog.

false

A sounding is a three-dimensional vertical profile of temperature, dew point, and winds.

false

Known as Modal Relief Models, statistical forecasts are made routinely of weather elements based on the past performance of computer models.

false

Lows tend to move away from the region of greatest surface pressure drop, whereas highs tend to move away from the region of greatest surface pressure rise.

false

Probably the easiest weather forecast to make is a farmer's forecast, which is simply a prediction that future weather will be the same as present weather.

false

The difference between progs for the same level in the atmosphere may result from the way the models use the equations, or the distance between grid points, called persistence.

false

The meteogram is a chart that shows how one or more weather variables has stayed the same at a station over a given period of time.

false

Advisories are issued to inform the public of ________ conditions caused by wind, dust, fog, snow, sleet, or freezing rain.

less hazardous

A(n) ________ forecast is one that extends from about 3 to 8 days (192 hours) into the future.

medium-range

As late as ________, all weather maps and charts were plotted by hand and analyzed by individuals.

mid-1950s

What type of forecast predicts the weather for up to a few hours (usually not more than 6 hours)?

nowcast

The routine daily forecasting of weather by the computer using mathematical equations has come to be known as ________.

numerical weather prediction

The final forecast chart representing the atmosphere at a specified future time is called a ________.

prognostic chart

Beyond about ________ days, the accuracy of computer prog forecasts falls off rapidly.

seven

As a forecast extends further into the future, isobar lines usually look more and more like scrambled spaghetti, which is why an ensemble forecast chart is often referred to as a ________ plot.

spaghetti

A watch indicates that atmospheric conditions favor hazardous weather occurring over a particular region during a specified time period, but that ________.

the actual time and location of the occurrence is uncertain

The analogue method relies on the fact that existing features on a weather chart (or a series of charts) may strongly resemble features that produced certain weather conditions sometime in the past.

true

The ensemble forecasting technique involves running several forecast models—each beginning with slightly different weather information to reflect the errors inherent in the measurements.

true

With a little practice and regular observations of the sky, one should be able to make fairly good short-range local weather forecasts by interpreting the messages written in the weather elements.

true