METEOROLOGY FINAL

​Surface weather information is provided by more than ____ land-based stations and hundreds of ships and buoys providing surface weather information at least four times a day.

10,000

Each year, U.S. fire departments respond to more than ____ fires started by lightning in the United States.​

20,000

How hot is lightning?

34,000 CELSIUS (54,000 FAHRENHEIT)

climatalogy

A forecast based on the climate of a particular region

Dissipating stage (thunderstorm)

After the storm enters the mature stage, it begins to dissipate in about 15 to 30 minutes. The dissipating stage occurs when the updrafts weaken as the gust front moves away from the storm and no longer enhances the updrafts.

​A forecast method that compares past weather maps and weather patterns to those of the present is

Analogue method

Which of the following doesn't qualify as severe weather?

Continuous lightning

The first stage of a tornado life cycle is the ____ stage.​

Dust whirl

According to the Enhanced Fujita Scale, an ____ tornado causes only minimal damage, whereas an ____ completely demolishes a house and sweeps it off its foundation.​

EF-0; EF-5

Doppler radar is helpful for measuring precipitation, but not wind.

False

Is this statement true or false: "Lightning never strikes twice in the same place"?​

False

Opening windows during a tornado decreases the pressure on the opposite wall and therefore decreases the chances that the building will collapse.​

False

Scientists understand with certainty how clouds are electrified.​

False

Seasonal forecasts make specific predictions of rain or snow. (In this case, specific refers to exact amounts of rain/snow and on what dates)

False

Thunderstorms are a common phenomenon in areas dominated by subtropical highs.​

False

Weather technology has improved so much that a meteorologist can now accurately predict the precise location a tornado will form up to 7 days in advance.

False

Floods that develop rapidly with little or no advance warning are called ____ floods.​

Flash

Which severe weather event kills more people than any other annually?

Flash-flooding

GFS

Global Forecast System

Wall cloud

If humid low-level air is drawn into the updraft, a rotating cloud may descend from the base of the storm.

Multicell thunderstorm

In a region where there is strong vertical wind shear (speed and/or directional shear), the thunderstorm may form in such a way that the outflow of cold air from the downdraft never undercuts the updraft. In such a storm, the wind shear may be so strong as to create horizontal spin, which, when tilted into the updraft, causes it to rotate. An intense, long-lasting thunderstorm with a single violently rotating updraft is called a supercell.

____________________ are placed on buildings to protect them from lightning damage.​

Lightning rods

​Modern computer forecasting models have increasingly smaller grid spacing. This presents which of the following problems?

Many more computations are needed.

Violent tornadoes (with winds exceeding 180 knots) that contain smaller whirls rotating within them are called ____.​

Multi-vortex tornadoes

By definition, a "shelf cloud" is almost always ________, but will usually form at the leading edge of a ___________.

Nonsevere; thunderstorm

NAM

North American Mesoscale

There are many techniques involved in creating a weather forecast. Which of the following do not belong?

Numerical Modeling, Persistence, Farmer's Almanac

​Which forecasting method assumes that weather systems will move in the same direction and at the same speed as they have been moving?

Persistence Forecast

What do the reflectivity colors show?

Precipitation, the stronger the returned precipitation, the heavier the energy?

What is weather forecasting?

Predicting how the present state of the atmosphere will change over time.

RUC

Rapid Update Cycle

How do lightning happen, cap'n?

Separate regions containing opposite electrical charges must exist within a cumulonimbus cloud

In the United States, tornadoes are most frequent during the ____, and least frequent during the ____.​

Spring; winter

What is the most dangerous type of thunderstorm?

Supercell thunderstorm

A thunderstorm is a storm containing ____________________ and ____________________.

Thunder; lightning

A(n) ___________ is an intense rotating column of air that extends downward from the base of a thunderstorm with a circulation reaching the ground.

Tornado

Tornadoes have a distinct signature on the radar screen, known as the ____________________, which shows up as a region of rapidly (or abruptly) changing wind directions within the mesocyclone

Tornado Vortex Signature

Which is worse: tornado watch or warning?

Tornado warning

An anticyclone is moving slowly eastward. Southerly winds on the western side of the system will bring warmer and more humid air to the region. Therefore, afternoon temperatures will be warmer than those of the day before.

True

Sinking air warms, yet the downdrafts in a thunderstorm are usually cold.

True

The ASOS system is designed to provide nearly continuous information about wind, temperature, pressure, cloud-base height, and runway visibility at various airports.

True

Tornado frequency is highest during the spring and lowest during the winter when the warm surface air is normally absent.​

True

Tornadoes have occurred in every state, including Alaska and Hawaii.​

True

Lightning may occur from one cloud to another.​

True.

A(n) ____ atmosphere is essential for tornado development.​

Unstable

Decay stage

Usually finds the tornado stretched into the shape of a rope. becomes greatly contorted

Most often, tornadoes form with supercell thunderstorms in an environment with strong ____.​

Vertical wind sheer

WRF

Weather Research and Forecast Model

What do the velocity colors show?

Wind speed, etc. red means winds blowing away, green means blowing towards

persistence forecast

a prediction that future weather will be the same as present weather

HP Supercell

a supercell dominated by heavy precipitation, strong downdrafts (downbursts), and large hail. Tornadoes wrapped in this may be difficult to see.

Funnel cloud

a tornado that is beginning to form but whose circulation has not reached the ground. Perhaps only about 30 percent of funnel clouds become active tornadoes. When viewed from above, the majority of North American tornadoes rotate counterclockwise about their central core of low pressure. Some have been seen rotating clockwise, but those are infrequent.

Tornadoes are usually observed

ahead of cold fronts.

Mature stage (thunderstorm)

appearance of downdraft marks beginning, most intense part of storm, updraft and downdraft now constitute the cell. Lightning and thunder present.

Cumulus stage

as a parcel of warm, humid air rises, it cools and condenses into a single cumulus cloud. As the cloud builds, the transformation of water vapor into liquid or solid cloud particles releases large quantities of latent heat, a process that keeps the rising air inside the cloud warmer (less dense) than the air surrounding it. The cloud continues to grow in the unstable atmosphere as long as it is constantly fed by rising air from below. Insufficient time for precipitation, typically. No lightning / thunder during this stage.

Bow echo

as strong winds rush forwards along the ground, they sometimes push the squall line outward so that it appears as a bow or a series of bows on a radar screen

Microburst

beneath an intense thunderstorm, the downdraft may become so localized so that it hits the ground and spreads horizontally in a radial burst of wind. can induce damaging straight-line winds well over 100 knots. damaging to aviation. come from virga.

Shrinking stage

characterized by an overall decrease in the funnel's width, an increase in the funnel's tilt, and a narrowing of the damage swath at the surface, although the tornado may still be capable of intense and sometimes violent damage.

Numerical prediction

computers on Earth are devoted to weather and climate prediction. The routine daily forecasting of weather by computers using mathematical equations

multicell thunderstorm

contain a number of cells, each in a different stage of development; tend to form in areas of moderate to strong vertical wind shear; this type of shearing causes the cell inside the storm to tilt in such a way that the updraft actually rides up and over the downdraft. Notice also that precipitation inside the storm does not fall into the updraft (as it does in the ordinary cell thunderstorm), so the storm's fuel supply is not cut off and the storm complex can survive for a long time. Long-lasting multicell storms can become intense and produce severe weather for brief periods.

Mature stage

damage normally is most severe as the funnel reaches its greatest width and is almost vertical. when a tornado reaches its mature stage, its circulation usually stays in contact with the ground until it dissipates.

Heat lightning

distant lightning from thunderstorms that is seen but not heard, frequently appears on hot summer nights when the overhead sky is clear

mesoscale convective systems

driven by convective processes and because they are mesoscale (middle scale) in size. organized thunderstorms that can take on a variety of configurations

Dust-whirl stage

dust swirling upward from the surface marks the tornado's circulation on the ground and a short funnel often extends downward from the thunderstorm's base

Sheet lightning

forms when either the lightning flash occurs inside a cloud or intervening clouds obscure the flash, such that a portion of the cloud appears as a luminous white sheet, eh?

Ribbon lightning

forms when wind moves the ionized channel between each return stroke, causing the lightning to appear like it's hanging from the cloud

Supercell thunderstorms are different from ordinary thunderstorms in that supercell thunderstorms​

have a tilted, rotating updraft in the mature stage.

Ordinary cell thunderstorms most frequently form​

in the afternoon

Ball lightning

looks like a luminous sphere, often about the size of a football, appears to float in the air or slowly dart about for several seconds

Many flash floods, including the one that occurred in Colorado's Big Thompson Canyon, are the result of thunderstorms that​

move slowly

Squall line

multicell thunderstorms may form as a line of thunderstorms. form directly along a cold front and extend for hundreds of miles, or the storm may form in the warm air 100 to 300KM ahead of the cold front

The forecasting of weather by a computer is known as​

numerical weather prediction.

​What would be the least accurate forecast method of predicting the weather two days into the future during changeable weather conditions?

persistence forecast

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. To the forecaster, the weather map "looks familiar." pattern recognition

Mesocyclone (the rotating updraft)

rotating air column on the south side of the storm, usually 5 to 10 kilometers across, so strong that precipitation cannot fall through it. This situation produces a rain-free area (called a rain-free base) beneath the updraft. Strong southwesterly winds aloft typically blow the precipitation northeastward

Ordinary ("Pop-Up") T-Storm

scattered thunderstorms, typically form on warm humid days, tend to form in warm, humid air masses away from significant weather fronts. These thunderstorms can be considered "simple storms" because they rarely become severe, typically are less than a kilometer wide, and they go through a rather predictable life cycle from birth to maturity to decay that usually takes less than an hour to complete. Limited vertical wind shear.

An ensemble forecast goes further and further into the future, the forecast lines can become scrambled. Such a chart is often referred to as a​

spaghetti plot.

Derecho

straight-line winds gusting to more than 50 knots (58 mi/hr) persist along a path at least 400 km (250 mi) long, However, with a derecho, debris is blown in one direction and generally over a wide area, whereas debris with a tornado is usually thrown in many directions.

Trend method

surface weather systems tend to move in the same direction and at approximately the same speed as they have been moving, providing no evidence exists to indicate otherwise

LP Supercell

tend to produce little rain, they are still capable of producing large hail as well as tornadoes. The rotation is often visible in a bell-shaped central tower, with a corkscrew-like pattern along its sides. Tornadoes are clear and visible

No country experiences more tornadoes than ____.​

the United States

organizing stage

the tornado increases in intensity with an overall downward extent of the funnel

When a large number of tornadoes develop in association with a particular weather system (typically six tornadoes or more), it is referred to as a ____.​

tornado outbreak

A tornado ___________ is issued once a tornado is spotted, either visually or on a radar screen.​

warning

About 70 percent of all tornadoes in the United States develop from ____.​

​March to July

​A weather watch would probably be issued for which of the following conditions?

​There is a chance for tornadoes this afternoon/evening.

Squall line thunderstorms generally form​

​along or ahead of a cold front.

When caught in a thunderstorm in an open field, the best thing to do is to​

​crouch down as low as possible while minimizing contact with the ground.

The forecasting technique that produces several versions of a forecast model, each beginning with slightly different weather information to reflect errors in the measurements, is called​

​ensemble forecasting

​A weather warning indicates that

​hazardous weather is either imminent or occurring within the forecast area

An ordinary thunderstorm​

​is a scattered/isolated storm and normally not severe.

For ____ to occur, separate regions containing opposite electrical charges must exist within a cumulonimbus cloud.​

​lightning

The tornado alley of the United States ____.​

​stretches from central Texas to Nebraska

During the summer, what conditions prevail near the surface over the Great Plains that help a hailstone survive as ice all the way to the ground?​

​strong updrafts

Supercell thunderstorms differ from ordinary cell (air mass) thunderstorms because​

​the updraft in a supercell thunderstorm is longer-lasting and rotates.