Want to hear more about storms? Check out the transcript of a message board discussion with Weather Expert, Ingrid Amberger.
Dr. Jeffrey Masters, Director of Meteorology for the Weather
Underground Web site, answered student weather and winter storm questions
in the winter of 2001.
Dr. Masters received his B.S. and M.S. degrees in Meteorology
from the University of Michigan. He has taught weather forecasting at
the State University of New York at Brockport, and joined the Hurricane Hunters
as a flight meteorologist for the National Oceanic and Atmospheric Administration's
(NOAA) Aircraft Operations Center. You can see him in the 1988 PBS documentary
NOVA show "Hurricane!" flying into Hurricane Gilbert.
My friend and I are doing a science fair project, and we would like to know which town would receive more snow a town in the valley or a town near a mountain?
Most likely, a town near a mountain. Mountains act as giant rain
catchers precipitation is almost always higher on a mountain
compared with surrounding valleys. This is because when air hits a
mountain, the air is forced upwards. Upward-moving air cools, and if this
cooling is great enough, the air will cool to the point where it cannot
hold any more water vapor. This water vapor then condenses, and falls as
rain or snow.
do air masses differ from each other?
upon where they start. An air mass that sits a long time over a hot, wet
ocean will become hot and wet. An air mass that sits a long time over a
cold, dry place will become cold and dry.
which direction does weather move: north/south or west/east?
can move in any direction. In the United States, weather most
often moves west to east, because that is the direction the
jet stream blows. The jet stream carries weather systems along
with it. Now, you may ask, why does the jet stream blow west
to east? The answer is complicated, but it happens as a result
of the way the sun heats the equator more than the poles,
and the speed with which the earth spins.
do you know that all the snowflakes have their own pattern?
has been a lot of research done on the subject by many scientists.
Scientists capture snowflakes and photograph them to study
it going to snow a lot this year?
I knew the answer to that question, I'd be rich! Long-range
forecasting of winter snow is more luck than science right
you believe there are volcanoes under the ocean water, off
the coast of Peru, that affect El Niño?
I don't think so I don't think volcanoes are
big enough to compete with the forces of the global winds
which cause the El Niño.
exactly is sleet?
Sleet happens when the air temperature is above freezing
near the clouds, where the rain is formed, and below freezing
near the surface of the earth. As the rain drops, they fall
through the thick layer of below-freezing air, and the
raindrops freeze before they hit the ground. These frozen
raindrops are called sleet.
the difference between dew point and humidity?
The dew point is the temperature the air must reach in
order to achieve 100 percent relative humidity the point
where the water vapor in the air starts condensing and clouds
the hottest place that it has ever snowed?
The farthest south is has ever snowed in the continental
United States is Miami Beach, Florida, in 1977.
Oregon so wet?
Oregon is so wet because the winds usually blow from west
to east over the state. On the west side of the state, along
the Pacific coast, the air is very moist. The air currents
take this moist air and move it into the mountains, which run
the entire length of the state. When moist air hits a mountain,
the air is forced upwards. Upward-moving air cools, and if this
cooling is great enough, the air will cool to the point where
it cannot hold any more water vapor. This water vapor then condenses, and falls as rain or snow.
tools do you use to predict weather?
Weather data is gathered by weather instruments at over
10,000 airports worldwide, from weather balloons launched
twice daily from about 1,000 locations around the world, and
from weather satellites orbiting the earth. The first task in
making a forecast is to look at these current measurements of
the atmosphere and understand what the weather is doing now.
It also helps to watch some time-lapse weather animations to
see what has been happening over the past day or so, and make
some estimates of how these trends will carry over into the
future. Finally, we review the forecast made by supercomputers,
and base our forecasts on those predictions basing the
final forecast on our analysis of the current weather, on
weather trends, and our past experience.
you predict if there will be a tornado?
Tornadoes always form inside severe thunderstorms. Usually,
a large area of clouds inside of the thunderstorm will start to
spin about 30 minutes before a tornado appears. So, once we see
this spin start to develop, a tornado warning can be issued.
However, not all spinning thunderstorms make tornadoes, so there
are a lot of false warnings issued.
More information about tornadoes can be found in the
Tornadoes section of Weather Watch.
Please explain lake effect. I live in Michigan.
Any lake, if it is large enough, will change the weather around it. The effect is most noticeable in America around the Great Lakes area in winter. Cold air blowing across the lakes picks up large amounts of moisture as it passes over the relatively warm water beneath. When these moisture-laden winds hit the shore, they drop the moisture as "lake-effect" snows that are frequently very heavy up to three inches per hour!
When you chased hurricanes, how many would you say you chased? What was it like?
Is snow safe to eat?
I chased six hurricanes, and about six weaker tropical storms and tropical depressions. You can read my account of my flight into Hurricane Hugo.
Not if it's yellow!! Actually it depends on how much contamination is in the air the snow falls in. If you are in a heavily polluted city, odds are the snow has lots of contaminants in it from auto exhaust, factory emissions, etc. That snow is not too healthy to eat. However, in rural or suburban areas, eating a little snow probably wouldn't hurt.
is the difference when a weather reporter says "partly cloudy"
or "partly sunny"?
There is no difference. It's the weather reporters way of saying the glass is half-empty or half-full.
Why does thunder make noise?
Thunder is the sound of air rushing in to fill a partial vacuum created when lightning passes through the air.
Why is the snow white?
A: Snowflakes have a very complicated shape with lots of reflecting surfaces. When the white light of the sun hits a snowflake, so much of the light gets reflected back that we see the full white light of the sun scattered back to our eyes.
What is the average amount of rain Hawaii gets every year?
A: Well, it depends on where you are in Hawaii.
Honolulu, which is shielded by tall mountains from the moist northeast
trade winds blowing off the ocean, gets only 22 inches of rain per year.
But Hilo, on the northeast side of the Big Island of Hawaii, has no protecting
mountains, and gets 130 inches per year.
Which country gets the most rain every year?
Some mountainous areas of India receive over 400 inches of rain per year, primarily during their monsoon season.
Why does it get more humid in some places than others?
You need three things to get high humidities:
1) You need to be close to a major body of water (preferably a warm one, like the Gulf of Mexico).
2) The wind must blow from that large body of water towards you.
3) There cannot be a range of mountains between you and the body of water, or else the mountains will intercept much of the moisture.
is there water vapor inside clouds? How did it get there in
the first place?
Water vapor's original source is from evaporation from
the oceans, lakes, streams, or any other bodies of water.
The sun's heat creates updrafts that lift the water vapor
high in the atmosphere, where it is cold enough to condense
the water vapor into cloud drops.
are the most important things you need to do to be prepared
for a hurricane?
ready to evacuate if the order comes.
loose objects around your home; board up (DON'T TAPE) your
sure you have a weather radio, flashlights, fresh water, plenty
of food, and gas for your car, etc.
information about emergency preparedness, visit FEMA's Ready site for kids. FEMA stands for Federal Emergency Management Agency. It is the federal agency responsible for helping people before and after disasters.
does wind start?
Wind always starts because two areas have different pressures
or densities of air. The wind will always blow to try to equalize
these differences, so the wind blows from high to low pressure.
did you want to be a weather person?
Well, growing up in the Midwest with its amazing variety
of weather always made me want to learn more about it.
is meant by Indian summer?
A: Sometimes during mid or late fall, a period of unseasonable
warm weather occurs with clear skies, sunny but hazy days,
and cool nights. Indian summer doesn't happen every year,
and sometimes happens more than once in the same year.
long can a blizzard last?
A: Blizzards usually last only a day in one location, since
the jet stream usually moves them along pretty quickly. Sometimes,
though, you get a "cut-off low," which is a storm system that
is cut off from the jet stream. These cut-off lows
can create blizzards (particularly in mountainous regions)
that can last as long as a week.
is the hottest temperature it has ever been in history?
A: On September 13, 1922, at El
Azizia, Libya, the recorded temperature was 136° F (58°
global warming a threat to the Midwest?
A: Global warming is a threat to every region in the world,
since climate change will occur everywhere. In the short term,
it will seem like any change to the current climate in a region
will be costly, since humans will be forced to adapt to whatever
the new climate is. However, it is possible that global warming
in the Midwest might be beneficial in the long run. It could
increase the amount of rainfall along with the hotter temperatures.
These conditions would mean a longer growing season, and that
would mean increased crop yields for the farmers in the area.
does it mean that the ozone layer is being destroyed?
A: Human-created chemicals called chlorofluorocarbons
(CFCs) have drifted up into the stratosphere, where they are
attacking and destroying the protective layer of ozone. Destruction
of the ozone layer lets more ultraviolet rays reach the earth's
surface. This is dangerous to life on earth since overexposure
to harmful ultraviolet rays can cause sunburn in humans and
lead to many other problems for plant and animal life.
Q: What is hail made out of?
A: Ice. A hailstone starts off as a small chunk of
ice. Winds blow the ice through parts of the thunderstorm where the cloud
water is supercooled. What is special about supercooled cloud water
is that it exists as a liquid even though the temperature is below freezing.
As the hailstone travels through the supercooled water drops, the liquid
water freezes onto it, making the hailstone grow larger.