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240 Cards in this Set
- Front
- Back
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Define Meteorology |
a. study of the atmosphere and its processes b. the study of atmospheric phenomena |
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Weather |
a. short-term b. state of earth's atmosphere at a particular time and place |
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Climate |
a. long-term b. range of weather conditions at a place |
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Hydrometeor |
a. wet things in the air such as raindrops b. the "meteor" in meteorology refers to this |
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Weather Folklore |
people ascribed weather events, good and bad, to spirits, gods, or other mysterious causes beyond human understanding |
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Weather Proverbs |
"rules" based upon close observations of the clouds, the winds, and other weather elements to offer guidance about the future weather (farmers and sailors) |
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Define Science |
process for investigating phenomena, acquiring new knowledge, correcting or integrating previous knowledge |
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A "Good" Science Question |
something you can measure or test |
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A "Good" Hypothesis |
an educated guess or theoretical explanation, establishes a relationship, and expresses what you think the results of your experiment will show |
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Scientific Method by Scientists |
a. engage in many activities in many different sequences; ongoing b. depends on collaboration with other scientists c. not a linear process |
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Scientific Method by School Science Projects |
a. linear process b. starts with a question and ends with a conclusion c. usually done by one person |
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Why is science considered a process |
a. it's ongoing, unpredictable, self-correcting b. it often requires repeating the same steps to account for new information and ideas c. it has many different steps d. in science, all ideas are tested |
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Why do Scientists use the Scientific Method? |
a. helps to ensure repeatability b. helps to minimize the influence of bias or prejudice in an experimenter when testing a hypothesis or theory (personal, religious, and cultural beliefs influence our perceptions and interpretations of phenomena) c. smart people can come up with good explanations for mistaken points of view |
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Define Scientific Consensus |
a. the collective position of the community of scientists in a particular field of study b. implies general agreement on a conclusion, not unanimity c. achieved primarily through the peer review process |
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How a weather forecast involves using the scientific method |
a. weather forecasting is an application of science as a process b. in weather forecasting you have to make observations, ask the question such as "What is the weather going to be like tomorrow?" (from this question a hypothesis about tomorrow's weather is formed c. experimentation begins with the collection of data about the atmosphere d. then the data is analyzed and put onto maps about the weather e. maps are then sent to forecasters who use the maps and personal experience to make a forecast f. conclusion is the final forecast seen usually on the TV/Internet (however, past the final forecast, new data is always being collected on the current, immediate, and future weather) |
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News Article Credibility (First Considerations) |
a. What is the general topic of the article? b. Who published and/or wrote the article? c. What potential biases exist in either the reporting or the research? |
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News Article Credibility (Next Considerations about the study reported on in the article) |
a. Who conducted the study described in the news article? Is their area of expertise stated? b. What was the purpose of the research reported in the article? That is, what general question did the study seek to answer? c. How was the study designed? That is, what experiment(s) did the scientists formulate and conduct and how did they carry them out? (this includes the analysis of any data that were collected or simulated with computer models) d. What were the conclusions of the study? e. What observations or experience led the scientists to conduct the study described in the news article? f. What possible explanation or hypothesis, was given to explain the observation or question? |
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What is included in a conclusion of a scientific study? |
a. the results b. discussion of casual mechanisms for the scientists' findings c. implications of the study d. questions that may have been raised about the reliability or validity of the study |
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Define National Weather Service |
the government's main forecasting agency (it also conducts research) it's located within the department of commerce |
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Why do discrepancies exist in reports of weather impacts? |
a. there is no centralized method for collecting impact data b. no standard methodology for assessing impacts |
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Direct Impact v Indirect Impact (examples) |
Direct: Person dies from hypothermia
v. Indirect: Person with heart disease dies from heart attack while shoveling snow Direct: Crops die from prolonged drought v. Indirect: Cost of cereal increases due to drought |
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Define Atmosphere |
relatively thin layer of gases and suspended particles that surround the Earth |
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Primary gases that comprise the atmosphere in descending order of concentration |
1. Nitrogen- 78.08% 2. Oxygen- 20.95% 3. Water- 0-4% 4. Argon 5. Carbon Dioxide 6. Neon 7. Helium 8. Methane 9. Hydrogen 10. Nitrous Oxide 11. Ozone |
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Define Aerosol |
solid particles or liquid droplets that are suspended in gas |
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The significance of a gas in the atmosphere isn't necessarily related to the concentration (explain and give an example) |
Carbon Dioxide and Water Vapor have relatively small concentrations but are extremely important for life to exist as we know it |
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How the thickness of the atmosphere compares to the size of the Earth |
It doesn't have a definite upper boundary, it slowly thins into outer space. Most of it's mass is concentrated at an altitude below approx. 18 miles |
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Why does the thickness of the atmosphere vary with temperature? |
a. Where temps are cold, air molecules contract and the atmosphere has a shallower depth b. Where temps are warm, air molecules expand and the atmosphere has a greater depth |
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Temperature profile of the troposphere and stratosphere |
a. Increasing altitude in the troposphere= Colder b. Increasing altitude in the stratosphere =Warmer |
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What layer of the atmosphere has the protective ozone layer? |
Stratosphere |
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Explain why weather primarily occurs in the troposphere |
Favorable temperature structure and presence of water vapor |
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State components that make a cloud visible |
small VISIBLE droplets of liquid water or small ice crystals or both |
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Size of cloud drops v. rain drops |
a. Cloud Drop- 20 microns (1000 microns=1 millimeter) b. Rain Drop- 2 millimeters |
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Identify mechanisms that cause air to rise |
a. surface heating b. topography c. weather fronts d. convergence |
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Summarize the process by which clouds form |
a. As air rises it cools and expands (air cools due to expansion NOT because temps are colder higher in the atmosphere) b. Most air masses have invisible water vapor, so as the air mass rises and cools, this invisible water vapor condenses onto condensation nuclei (aerosols like dust, salt, and smoke) and then become visible |
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Cirro |
high |
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Alto |
Middle |
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No Cloud Level Abbreviation |
Low |
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Strato |
layered |
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Cumulo |
Puffy, heaped |
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Nimbo |
Rain, Precipitation |
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Cirro |
Wispy, Curl |
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Why do clouds sometimes appear dark |
after bending around a drop, light waves merge. a wave crest combining with the trough of another wave forms a dark area |
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Explain what it means if an object absorbs energy |
the object takes in energy and transforms it to heat = temperature increases |
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explain what it means if an object reflects energy |
energy bounces off, redirects energy, it doesn't result in a temperature change |
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Explain what it means if an object transmits energy |
a. light goes through a surface of an object b. no change in direction of energy or quality of energy c. no temperature change takes place |
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Explain what it means if an object emits energy |
a. all objects give off energy ex. sun emits or gives off energy |
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List the 4 physical laws which describe the properties of electromagnetic radiation |
1. All objects emit and absorb energy (radiation) 2. The total energy emitted is proportional to the temperature 3. Wavelength of the most intense radiation emitted is inversely proportional to temperature 4. Interactions of energy in the Earth-Atmosphere depend on wavelength and medium |
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4 ways energy is transferred in the atmosphere |
1. Radiation 2. Conduction 3. Convection 4. Advection |
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Radiation |
transfer of energy without physical substance a. passes through the atmosphere, interacts with air molecules and heats them |
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Conduction |
transfer of energy by direct contact between substances a. energy is always transferred from high to low temperature |
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Convection |
transfer of energy by movement of molecules within a fluid a. process we see when we see cumulonimbus clouds forming |
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Advection |
transfer of energy by movement of molecules within a fluid in the horizontal direction a. caused by wind |
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Describe the difference between advection and convection |
advection- horizontal transfer convection- vertical transfer |
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Describe the similarity between advection and convection |
both are movement of molecules within a fluid |
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Explain how the atmosphere near the surface of the Earth is warmed from below |
Sequence: a. shortwave-radiation from the sun is emitted toward the earth b. surface absorbs the sun's energy causing it to warm c. air molecules in contact with Earth's surface warm by conduction d. these warm, less dense air molecules rise and replace cooler, more dense air molecules through convection it is also warmed because earth emits long wave radiation |
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Explain what a balanced energy budget means in terms of incoming and outgoing radiation |
the amount of incoming radiation should equal outgoing radiation |
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Give an example of an energy imbalance in terms of incoming and outgoing radiation |
since the sun is more directly above the tropics than the poles, the tropics receive more energy than they lose to space, and the poles lose more energy to space than they receive |
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What are the implications of an imbalance from the temperature of the earth? |
when the amount of incoming radiation doesn't equal outgoing radiation, the average temperature of the earth warms |
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What help to regulate the energy imbalance? |
storms |
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How do storms regulate the energy distribution across the surface of the Earth? |
a. storms take heat, stored in the ocean, and transfer it to the upper atmosphere where the upper level winds carry that heat to the poles b. this keeps polar regions from being as cold as they could be and helps keep the tropics from overheating |
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3 ways that the atmosphere bends light |
1. reflection 2. scattering 3. refraction |
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reflection |
redirection or bouncing off; light leaves an object at the same angle it arrives |
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scattering |
like reflection, but occurs in all directions |
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refraction |
bending of light caused by changes in density |
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Describe the 3 step process of how rainbows form |
Refraction, Reflection, Refraction a. sunlight enters a rain drop and is then REFRACTED b. some of the light is REFLECTED back into the drop itself c. then, upon leaving the droplet, the light is REFRACTED again, exiting the drop in a diverse spectrum of colors from violet to red |
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Primary Rainbow |
a. one reflection b. ROY G BIV c. brighter |
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Secondary Rainbow |
a. two reflections b. colors reversed (VIB G YOR) c. fainter- more light escapes |
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What is the basic cause of the optical phenomena such as halos and sun dogs |
ice crystals in the atmosphere that refract and reflect light |
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Explain why the sky appears blue |
a. gas molecules (oxygen and nitrogen) and aerosols scatter sunlight b. blue is scattered more efficiently because it travels in shorter wavelengths and has a greater chance of hitting a tiny molecule |
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Explain why sunrises and sunsets appear red |
a. Sun's rays pass through more of Earth's atmosphere when the sun is low in the sky b. more red light is scattered because the sun's rays have to pass through more of the earth's atmosphere to reach you than it does when the sun is overhead c. red light has the longest wavelength so it is 1st to appear at sunrise and last to disappear at sunset |
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Explain why the sky can appear white |
a. occurs when particles of dust, pollution, and water in the lower atmosphere are comparable (or larger) than the wavelength of light b. all colors of light to be scattered more or less equally |
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define air pressure |
force applied by air on a unit surface area (weight of the air molecules above a given area) |
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define barometer |
used for measuring air pressure (mercury and aneroid) |
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explain the basic principle by which a mercury barometer works |
a. air pushes down on mercury b. mercury in the glass tube rises |
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What is the value of average sea level pressure in millibars? Approx. how much is this in lbs. per square inch? |
a. 1,013.25 mb b. 15 lbs per square inch |
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What units do meteorologists in the US use for measuring pressure? |
millibars (mb) |
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define sea level pressure |
the pressure that would exist if the station were located at sea level |
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define station pressure |
the pressure measured at a given station (location) |
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Meteorologists use maps of sea level pressure because station pressure maps reflect more than changing weather conditions. Station pressure also changes due to |
elevation |
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define cyclone |
low pressure system a. zone of pressure lower than that of the surrounding areas b. moving in any direction away from the "low"= a increase in pressure |
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define anticyclone |
high pressure system a. zone of pressure higher than that of the surrounding areas b. moving in any direction away from the "high" = decrease in pressure |
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explain the statement, "the lower the barometric pressure, the stronger the hurricane" |
a. air moves as wind from higher pressure toward lower pressure b. the greater the pressure difference, the stronger the force pushing the air |
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define wind |
the movement of air |
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at earth's surface how do winds flow around a low pressure system? a high pressure system? |
low- counterclockwise; inward high- clockwise; outward |
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define pressure gradient force |
a. sets wind in motion b. caused by differences in air pressure over a distance c. high to low |
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explain the role of the pressure gradient force in the generation of the wind |
a. it sets the wind in motion |
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why are horizontal pressure gradient forces are smaller than vertical pressure gradients forces? |
the steeper (more vertical) the pressure gradient, the larger the pressure gradient force |
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define Coriolis Force |
a. apparent force caused by the rotation of the Earth b. deflects objects from their path of motion relative to the Earth's surface (North Hemisphere= deflects right; South Hemisphere= deflects left) |
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What properties of wind does the Coriolis Force impact? |
Motion of the wind in relation to the Earth (direction) a. only affects DIRECTION of an object, and not it's speed (if the earth didn't rotate, there'd be no Coriolis force, so it can't change an object's speed |
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What factors determine the magnitude(strength) of the deflection of the Coriolis Force? |
a. velocity of moving object b. latitude c. deflection increases with increasing latitude d. deflection depends on hemisphere |
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define friction |
a force that acts in an opposite direction to movement |
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How does friction affect the speed of winds near the surface? |
speeds of wind are slower near the surface because of frictional drag (only important in about the lowest mile of the atmosphere) |
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How does the change in wind speed caused by friction ultimately affect the direction of winds near the surface? |
friction slows the wind and reduces the deflection caused by the Coriolis Force |
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High rise buildings are particularly vulnerable to hurricane winds at the higher levels. Explain why |
because when air converges toward the low, there is no where for it to go except up |
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define jet stream |
fast moving currents of air in the upper atmosphere (20,000 to 40,000 feet or more above the surface) |
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What causes the jet stream to move northward in the summer |
the largest temperature gradient is in the north and the jet stream moves to follow the position of the largest temperature gradient
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define latent heat |
energy required for, or released by, a transition of a substance between phases |
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In molecular terms, explain the difference between ice, liquid water, and water vapor |
ice- individual water molecules are fixed in place and they vibrate next to each other (ordered) liquid water- molecules can move past one another, bump into each other, but remain relatively close to one another (semi ordered) water vapor- most energetic, molecules move quickly and independently and are not confined by intermolecular forces (random) |
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What happens to the temp of an object when you take energy away from it? |
temp decreases |
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when ice melts the water molecules must acquire additional energy to break the molecular bonds holding them together. where does this energy come from? |
the energy is pulled from the atmosphere |
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when a cloud forms does the air around it warm or cool? explain |
Warms a. molecules must release energy to slow down the molecules so the molecules can rebond b. energy is released into the atmosphere |
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when snow melts does the air around it warm or cool? explain |
Cools a. molecules must use energy to speed up the molecules and break bonds b. energy is used (pulled) from the atmosphere |
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In which phase are the bonds holding the molecules the strongest |
solid phase |
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which change of phase warms the atmosphere the most and why |
gas to solid -releases most energy for molecules to rebond |
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which change of phase cools the atmosphere most and why |
solid to gas -uses most energy to break down molecule bonds |
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why is latent heat important to the development of severe weather |
the latent heat that condensing water vapor or freezing water drops add to rising air accelerates the rising of the air (air is unstable) |
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define humidity |
amount of water vapor in the air |
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Saturation is considered a condition of equilibrium. What two things are equal |
Condensation=Evaporation |
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What atmospheric property determines the amount of moisture that can exist in the air at saturation |
temperature |
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If you heat air, the number of water molecules that can exist in that air increases. Why? |
Increases average speed of water molecules more water molecules can escape their bonds and enter the air |
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define relative humidity |
percent of water vapor in the air compared to what would be present if the air were saturated |
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relative humidity's values depend on what 2 variables |
1. amount of water vapor that can exist at saturation 2. actual amount of water vapor in the air |
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What are 4 mechanisms by which air rises and creates clouds? |
1. Convection 2. Convergence 3. Topography 4. Frontal Lifting |
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define adiabatic process |
temperature change without adding or removing heat (caused by mechanical heat) |
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what causes adiabatic processes to occur in the atmosphere |
as air rises, air pressure lowers, air molecules expand and have to use energy to expand, so air temp of molecules decreases |
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define air parcel |
volume of air that has its own temperature characteristics separate from the surrounding air - "blob" of air |
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what will a rising air parcel do in an unstable environment |
rises on its own after an upward push |
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what will a rising air parcel do in a stable atmosphere |
rise after an upward push and then sink back to original position. vertical motion of parcel is inhibited |
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why does an air parcel cool as it rises |
as air rises it expands |
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explain why a rising parcel of unsaturated air cools faster than a rising parcel of saturated air |
saturated air has condensation and as water vapor changes to liquid water, heat is released and the heat released offsets the cooling |
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Unsaturated rate of cooling for a rising air parcel |
5.5 F/ 1000ft |
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Saturated rate of cooling for a rising air parcel |
3.5 F/ 1000ft |
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define ASOS |
Automated Surface Observing System |
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basic elements measured by an ASOS |
a. sky condition b. visibility c. basic present weather info d. obstructions to vision e. pressure f. temperature and dew point temperature g. wind h. precipitation amount and type |
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define station model |
type of shorthand for representing weather conditions on a map |
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elements shown on a station model |
a. temperature b. dew point temperature c. wind direction d. wind speed e. cloud cover f. barometric pressure g. present weather |
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define radiosonde |
lightweight cardboard box package of instruments combined with radio transmitters that send data back from a weather balloon |
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define sounding |
a set of data measuring the vertical structure of an atmospheric variable (such as temperature) |
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What are the basic weather elements measured by a radiosonde? |
a. temperature b. dew point temp c. pressure d. wind measures all of these elements throughout the depth of the troposphere and into the lower stratosphere |
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how many times a day are radiosondes launched |
2 times a day |
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what eventually happens to a weather balloon when it reaches the stratosphere |
the balloon expands once it is stretched to it's limit, the rubber bursts and the radiosonde plummets back to earth happens because air pressure decreases |
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how do the number of surface observation sites over the US compare to the number of radiosonde launch sites |
larger number of surface observation sites than radiosonde launch sites ( only 92 radiosonde launch sites compared to TONS of surface observation sites) |
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How would reducing the number or frequency of weather balloon launches impact weather forecasts? |
a. reduce the amount of data (extreme data loss) b. reduce the quality of the data for computer models c. more errors would occur in day to day forecasts and during severe weather |
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what does the acronym RADAR stand for |
Radio Detection And Ranging RA- RAdio: a band in the electromagnetic spectrum D- Detection: of targets AR- And Ranging: using the radar signal to detect how far away the target is |
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In what part of the electromagnetic spectrum does radar transmit and receive energy |
microwave part (type of radio waves) |
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What type of radar images do we typically see on the news |
reflectivity based |
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what types of information does a radar reflectivity image provide |
a. rainfall rate b. rainfall accumulation c. storm motion d. presence of hail e. thunderstorm shape and height |
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what types of information does a radar velocity image provide |
motion (winds) toward or away from radar |
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what do the reds and yellows represent on a radar reflectivity image when it is in precipitation mode |
red= intense precipitation or even hail yellow= light rain |
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what do red represent on a radar velocity image |
you have motion AWAY from the radar |
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a hook echo is a feature of which type of radar image |
radar reflectivity image |
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the strength of the signal returned by radar depends upon what characteristics of the precipitation |
a. size b. number or amount c. composition (water v ice)- water returns more than ice, but hail returns the most |
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Explain how weather radar detects precipitation |
a. radar send out a pulse of energy in the form of a microwave b. the wave encounters a target (precipitation) c. the energy then scatters and some of that energy is returned to the radar |
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explain how the weather radar detects wind speed |
the Doppler effect shifts the frequency of the radar reflection based on the speed of the target allowing for the accurate measure of speed |
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identify an advantage of using radar estimated precipitation |
gives information over a much larger area and can see rain that occurs between ASOS station sites |
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identify a disadvantage of using radar estimated precipitation |
sometimes radar detects things that aren't precipitation, such as birds, bugs, debris, etc. |
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a NWS radar breaks down, explain how this could hinder a forecaster's ability to monitor nearby storms |
radar tells forecasters the direction and speed in which a storm moves and it tells the forecaster where the precipitation is occurring. |
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define geostationary satellite |
primary for weather satellites a satellite that travels around the earth at the same speed of earth -it is essentially looking at the same spot all the time |
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define polar orbiting satellite |
orbits around the poles as the earth rotates underneath -it only gets a view of the same location on earth every so often |
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what are the 3 primary channels used by GOES satellites to monitor the weather |
1. Visible 2. Infrared 3. Water Vapor |
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what does the GOES satellite visible channel detect |
visible radiation that is scattered off the Earth a. high amounts of visible radiation= white b. low amounts of visible radiation= dark |
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what does the GOES satellite infrared channel detect |
infrared energy (heat) emitted from the Earth's surface and atmosphere a. objects with high temp= dark b. objects with low temp= white |
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what does the GOES satellite water vapor channel detect |
detects infrared energy, but only the energy that is emitted from the _____________ ______________ in the atmosphere a. moist regions= white b. dry regions= dark |
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identify an advantage and a disadvantage to using visible satellite images |
advantage: easy to interpret disadvantage: no images at night; difficult to tell the clouds from snow |
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identify an advantage and a disadvantage to using infrared satellite images |
advantage: can help determine the type of clouds disadvantage: it can be difficult to distinguish between clouds and the ground; can miss areas of cloud cover |
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what do bright white and dark areas represent on the visible satellite image |
white: high amounts of visible radiation dark: low amounts of visible radiation |
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what do bright white and dark areas represent on the infrared satellite image |
white: low temp dark: high temp |
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what do bright white and dark areas represent on the water vapor image |
white: moist regions dark: dry regions |
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define extratropical cyclone |
well-defined surface low pressure center that is characterized by different air masses, which are separated by fronts (also mid-latitude cyclones) |
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where do extratropical cyclones occur (latitudinal range) |
outside of the tropics; between 30 to 60 degrees (North or South); zone of westerly winds |
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where are the preferred regions of extratropical cyclone formation for storms impacting the US |
a. Gulf of Alaska b. East of the Rockies c. Gult of Mexico d. East Coast |
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in general, in which direction do extratropical cyclones travel across the US |
west to east |
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how do cyclones balance temperature difference caused by unequal solar heating of the earth |
they move warm air northward and cold air southward |
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define air mass |
large body of air with generally uniform temperature and humidity |
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5 types of air masses |
1. continental arctic 2. continental polar 3. maritime polar 4. maritime tropical 5. continental tropical |
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continental arctic |
dry; very cold |
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continental polar |
dry; cold |
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maritime polar |
damp; cool |
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maritime tropical |
humid; warm |
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continental tropical |
dry; hot |
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define front |
transition zones between contrasting air masses classified by the advancing air mass |
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why can air be lifted along a dry line when there is no temperature differences between the air masses on either side of the boundary |
humid air is less dense than dry air, so the dry air lifts the humid air |
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explain why stationary fronts are often associated with flooding |
a. if there is enough moisture in the air, clouds and precipitation will form as warm air flows and condenses over top of cool air b. stationary fronts can stay in place or nearly in place for days c. this can cause excessive precipitation over an area and lead to flooding |
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define polar front |
the boundary that separates polar air masses in the north from warmer air masses in the south |
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step 1 in the lifecycle of an extratropical cyclone |
setting the stage: -a cold, high-pressure mass of air moves in from the NW. -a high pressure mass of air arrives from the SE -since neither air mass is displacing the other, the boundary between them isn't moving, it's a stationary front |
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step 2 in the lifecycle of an extratropical cyclone |
a wave forms: -cold air flows under less-dense warm air -warm air flows over colder, denser air -a wave forms on the stationary front |
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step 3 in the lifecycle of an extratropical cyclone |
the storm forms and grows: -the entire system is moving toward the east as the pressure falls in the low-pressure center |
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step 4 in the lifecycle of an extratropical cyclone |
the storm begins to die: -the low pressure center redevelops in the cold air north of the cold and warm fronts -the storm weakens as air pressure in the center rises -an occluded front forms |
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define ridge |
an elongated area of high atmospheric pressure |
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define trough |
an elongated area of low atmospheric pressure |
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define blizzard |
a severe weather condition characterized by high winds and reduced visibilities due to falling or blowing snow |
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does snow have to be falling for a blizzard to occur |
yes |
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what are three ingredients necessary for blizzard formation |
1. sustained winds or frequent gusts greater than or equal to 35 mph for 3 hours or more (STRONG WINDS) 2. cold temps 3. falling or blowing snow that reduces visibility to 1/4 miles or less |
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explain how cold temps help create blizzard conditions |
it helps create the high pressure area on the NW side of the low that causes a strong pressure gradient and high winds |
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where do most blizzards occur |
great plains |
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what is the role of the geography of north america in causing blizzards in the great plains |
Rocky Mnts=barrier -block moderate air from pacific ocean and west half of the US -funnel cold air down from Canada over the region -funnel warm moist air up from the Gulf -serve as an area where cyclones (parent of blizzards) originate |
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explain why blizzards associated with Colorado Lows have more snow than those associated with Alberta Clippers |
Colorado Lows tend to have more snow because they form close to the west coast and pacific ocean, pulling in moisture. |
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define ice storm |
a winter storm where there is substantial accumulation of freezing rain or freezing drizzle |
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define freezing rain |
liquid precipitation that freezes on contact with a cold surface, often producing an ice glaze |
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define sleet |
pellets of ice (frozen rain drops) |
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difference between the temp profiles conducive to sleet formation and to freezing rain formation |
a. Freezing Rain- starts as snow, falls through a fairly deep layer of warmth, melts completely, and then freezes upon contact with a cold surface b. Sleet- starts as snow, falls through a warm layer, but doesn't completely melt, then falls through a relatively deep cold layer where it refreezes |
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what are the main differences between warnings, watches and advisories? |
warning- issued when hazardous winter weather conditions are imminent of very likely to develop in the next 12-24 hours watch- issued when conditions are favorable for the development of hazardous winter weather, usually issued 12-48 hours in advance of an event advisory- issued when hazardous winter weather is expected, but conditions won't meet warning criteria (could cause significant inconvenience and caution should be exercised 12-48 hours in advance) |
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what are the 3 criteria used by the NWS to determine whether a blizzard warning should be issued? |
1. sustained wind or wind gusts of greater than or equal to 35 mph 2. falling or blowing snow reduces visibility to 1/4 mile or less 3. conditions are forecast to last at least 3 hours |
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describe wind chill factor |
a. describes what happens to exposed flesh when its windy and cold outside b. as wind speed increases, heat is carried away from the body at a faster rate, driving down both skin temp and eventually the internal body temp |
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define frostbite |
actual freezing of skin and body tissue |
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symptoms of frostbite |
a. loss of feeling b. white or grayish color c. waxy appearance |
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define hypothermia |
lowering of your body's core temperature -most of the caused by exposure to cold weather or immersion in a cold body of water |
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symptoms of hypothermia |
a. shivering; which may stop as hypothermia progresses b. slow, shallow breathing c. confusion and memory loss d. drowsiness e. slurred or mumbled speech f. loss of cooperation g. slow, weak pulse |
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define tropical cyclone |
a. low pressure systems that begin as unorganized collection of thunderstorms b. form over tropical oceans c. don't have weather fronts associated with them |
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define hurricane watch |
hurricane winds of 74 mph or greater are possible in the next 36 hours anywhere in the watch area |
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define hurricane warning |
hurricane winds are possible within 24 hours, and "preparations to protect life and property should be rushed to completion" |
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define hurricane |
name for tropical cyclones in the Northeast Pacific and Atlantic basins -east of International Dateline |
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define typhoon |
name for tropical cyclones in the Northwest Pacific basin - west of date line and north of equator -most tropical cyclones of any basins |
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define Saffir-Simpson Scale |
measures a hurricane's potential damage scale |
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define eye |
a. point about which the entire storm rotates b. usually develops when max sustained winds go above about 80 mph c. calm d. cloud free area of sinking air and light winds (less than 15 mph) e. generally sinks in size when the storm strengthens f. can measure 20-30 miles wide g. lowest surface pressure |
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define dropsonde |
a package of instruments designed to drop from an airplane by parachute to measure and radio back data on temperature, humidity, atmospheric pressure, and wind speed & direction |
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define eyewall |
a. thick ring of clouds surrounding eye b. strongest winds and heaviest rain c. intense upward motion due to convergence |
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define spiral rainbands |
a. organized thunderstorms b. alternating bands of rain/dry that increase in intensity toward the eye c. air rises within the spiral rain bands |
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define storm surge |
rapid rise in sea level that occurs as a hurricane approaches a coastline (deadliest hazard of hurricanes) |
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Why does the National Hurricane Center include the "cone of uncertainty" on their forecast maps? |
because the actual tracks of hurricane centers have stayed within the cone about 2/3 of the time. however, if a hurricane's center stays within the cone but comes near one of its edges, hurricane winds can be felt outside of the cone |
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why are hurricanes given names |
a. reduces confusion when more than one storm is occurring within a basin b. ease of communication between forecasters and general public regarding forecasts, watches and warnings c. allow for less error than if using latitude and longitude |
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how often are hurricane names repeated |
every 7th year |
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when is a hurricane name retired |
if a atom was so deadly/costly that it would be inappropriate to use it again |
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what happens when they run out of hurricane names on the list |
use the Greek alphabet |
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what does the national hurricane center use as a basis for assigning hurricane categories |
estimates of the hurricane's fastest sustained wind speed |
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what is the primary trigger mechanism for tropical thunderstorms |
easterly waves off the coast of Africa and over the Atlantic Ocean |
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Tropical Disturbance |
wind= 0-22 mph organized thunderstorm |
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tropical depression |
wind= 23-38 mph detectable decrease in pressure and closed wind circulation |
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tropical storm |
wind= 39-73mph assigned a name |
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tropical cyclone |
wind is greater than or equal to 74 mph |
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tropical cyclones are smaller than extra-tropical cyclones and have slower wind speeds than a tornado, yet they can be more dangerous than either of those. Why |
a. spread over a larger area (normally 100 miles across) b. fierce winds c. long lifetimes d. deadly floods |
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why are skies often clear in the eye of a hurricane |
a. air spirals into the low in an attempt to fill the low pressure region b. as air nears the eye, it rapidly rises until it is forced outward by the barrier formed by the tropopause -some of the air is forced back downward to the center of the storm -this air comes inward from all directions and sinks in the eye -sinking air warms by compression -this warming causes clouds to evaporate and leaves a clear area in the center of the storm |
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explain why conditions are calm in the eye of a hurricane |
a strong pressure gradient force balances the Coriolis force and the strongest winds never reach the exact center |
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why do the strongest winds in a hurricane occur on the right side of a hurricane in the direction that is is moving |
a. winds rotate around the eye, counterclockwise b. the storm winds to the east of the eye move in the same direction c. combine these two winds (a & b) d. on the left side, the storm winds and the hurricane movement are in opposite directions and you subtract the wind speeds |
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how does a deep layer of warm ocean water contribute to hurricane development |
a. warm air over the ocean surface rises and creates an area of low pressure b. evaporation creates humid air. when clouds form, energy is released to fuel the hurricane c. waves stir up the ocean water. if the layer is deep enough, cold water won't rise to the surface |
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how does an unstable atmosphere contribute to hurricane development |
a. warm air will rise, condense, and form thunderstorms b. an unstable atmosphere keeps rising air rising |
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how does a layer of humid air contribute to hurricane development |
dry air pulled into a tropical cyclone weakens it, so you need the layer of humid air to be approx. 15,000 feet deep |
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how does weak vertical wind shear contribute to hurricane development |
a. lets the storm grow b. keeps storm's latent heat focused over a small area, which allows for the storm to grow vertically and become stronger |
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why does the highest storm surge occur on the right front quadrant of a hurricane in the direction it is moving |
a. winds are strongest on the right side of the hurricane b. hurricane needs coastline |
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how does the depth of water close to shore affect the height of storm surge |
shallower the water, the higher the storm surge |
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why don't hurricanes form on or near the equator |
lack of the Coriolis Force at the equator means that winds cannot develop rotation around areas of low pressure |
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the max storm surge occurs in the... |
front right quadrant |
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the strongest winds occur in the... |
eyewall |
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the greatest threat for tornadoes is in the... |
front right quadrant |
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areas where precipitation is occurring... |
eye wall and spiral rain bands |
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area where the most precipitation is occurring... |
eye wall |
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area where the surface pressure is highest... |
outermost rain band |
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area where the surface pressure is the lowest... |
areas where air is rising |
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areas where air is rising... |
rain bands |
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area where air is sinking... |
eye; in between rain bands |
