Weekly Weather Question Answers

Tuesday, July 28th 2009, 11:24 am
By: News 9

Question: How can you predict that there will be flash flooding?

Answer: Based on research and experience, we know what rainfall rates produce flash flooding for most locations. So, if you see a slow moving storm over parts of OKC with a 2 inch per hour rainfall rate, then for many locations under the storm, flash flooding would be likely. 

Question: Why do leaves turn color in the Fall?

Answer: During the fall, days get shorter. That means the leaves get less sunlight – which they need to make chlorophyll. Chlorophyll is what makes the leaves green. As the green chlorophyll goes away we begin to see the yellows and oranges in the leaves.

Question: Does a cold winter depend on how hot the summer was?'

Answer: Winter weather is determined by numerous factors such as La Nina, el Nino Pacific decadal oscillation, the Arctic Oscillation and many other factors.

Question: Will there ever be a hurricane name Devante?

Answer: Not at this point. The names are determined years in advance.

Question: When do you think it's going to freeze in Oklahoma?

Answer: We are predicting it will freeze in Oklahoma by November 25.

Question: What's the weather going to look like in HD?

Answer: Really terrific!

Question: What direction do tornadoes spin in Australia?

Answer: They spin mostly clockwise but they do spin in both directions.

Question: What is dewpoint and why is it so important?

Answer: The dew point is an excellent measure of the amount of moisture in the air. For example, during potential severe weather we look for an ideal dew point of 60F or higher.

Question: How high are the clouds in the sky?

Answer: Some clouds are on the ground which is fog. Most of the higher clouds that are significant to us are 30 to 60,000 feet and made up of ice crystals.

WEEK 10:
Question: Can El Nino affect the climate?

Answer: Yes, but right now we have a La Nina, the opposite of El Nino. In other words the equatorial waters of the Pacific are below normal and cooling.

WEEK 11:
Question: How many different kinds of clouds are there?

Answer: There are too many to name! But below are the main cloud genera:

  • Altocumulus – altus and cumulus – high heap
  • Altostratus – altus and stratus – high layer
  • Cirrocumulus – cirrus and cumulus – thin and wispy and puffy
  • Cirrostratus – cirrus and stratus – thin and wispy and spreadout
  • Cirrus – thin and wispy
  • Cumulonimbus – cumulus and nimbus – rain-bearing heap
  • Cumulus – puffy
  • Nimbostratus - nimbus and stratus - rain-bearing layer
  • Stratocumulus - stratus and cumulus - layer and heap
  • Stratus – layer

WEEK 12:
Question: What are the most challenging and rewarding things about being a meteorologist?

Answer: Sometimes the most challenging times as a meteorologist are also the most rewarding. Days when there are tornadic outbreaks, we work long hours under stressful conditions. However, it is all worth it knowing that we are helping keep Oklahoman's safe.

WEEK 13:
Question: What is the worst tornado ever to hit Oklahoma?

Answer: The most deadly tornado to ever strike within the borders of the state of Oklahoma occurred on Wednesday, April 9, 1947 in the city of Woodward.

The costliest was on May 3, 1999 in Oklahoma City. It did $1,244,297,720 in destruction.

WEEK 14:
Qestion: What are the different types of precipitation?

Answer: There is rain, hail, freezing rain, sleet & snow.

WEEK 15:
Question: What's the difference between El Nino and La Nina?

Answer: El Niño and La Niña are extreme phases of a naturally occurring climate cycle referred to as El Niño/Southern Oscillation. Both terms refer to large-scale changes in sea-surface temperature across the eastern tropical Pacific. Usually, sea-surface readings off South America's west coast range from the 60s to 70s F, while they exceed 80 degrees F in the "warm pool" located in the central and western Pacific. This warm pool expands to cover the tropics during El Niño, but during La Niña, the easterly trade winds strengthen and cold upwelling along the equator and the West coast of South America intensifies.

WEEK 16:
Question: When it rains, why is there sometimes lightning and sometimes not?

Answer: Within this cloud, there are many electrons giving off their charges. The tendency of charges within a cloud is to have positive charges gather toward the upper portion and negative charges in the bottom of the cloud.

WEEK 17:
Question: How does condensation affect clouds?

Answer: Condensation is crucial to the water cycle because it is responsible for the formation of clouds. Clouds form when rising air, through expansion, cools to the point where some of the water vapor molecules "clump together" faster than they are torn apart by their thermal energy. Some of that (invisible) water vapor condenses to form (visible) cloud droplets or ice crystals. 

WEEK 18:
Question: What's the most snowfall Oklahoma City has ever received?

Answer: 13.5 inches during the Christmas Eve snowstorm in 2009.

WEEK 19:
Question: How do hurricanes get their name?

Answer: From 1950 to 1952, tropical cyclones of the North Atlantic Ocean were identified by the phonetic alphabet (Able-Baker-Charlie-etc.), but in 1953 the US Weather Bureau switched to women's names. In 1979, the WMO and the US National Weather Service (NWS) switched to a list of names that also included men's names.

Names for these storms are approved by a committee of the World Meteorological Organization. There are six lists of hurricane names. The names are reused every six years unless a storm creates enough havoc to have its name retired.

WEEK 20:
Question: Why is the inside of hail always darker than the outside?

Answer: When a hail stone is sliced in half it is common to notice hail rings. These rings are alternate shades of white. The whiter rings (soft ice) are produced by supercooled water and ice crystals coming in contact with the hailstone that is below freezing on the surface while the clearer rings (hard ice) are produced from water that is above freezing that freezes on the surface.

WEEK 21:
Question: Does water vapor rise when it rains?

Answer: Water vapor actually has to rise before a shower so that it can rain.

WEEK 22:
Question: How old were you when you knew you wanted to be a meteorologist, and what was it about meteorology that interested you?

WEEK 23:
Question: What's the difference between a tornado and a cyclone?


  • Are hundreds of miles wide.
  • Form only over warm ocean water.
  • Last for days and sometimes well over a week.
  • Produce rain and flooding in addition to powerful winds.
  • Are independent, self sustaining storm systems.
  • Have winds ranging from 74 to about 200 mph


  • Are rarely over a mile wide
  • Usually form over land
  • Usually last minutes, rarely a few hours
  • Cause damage via wind and debris
  • Are dependent on a large storm to develop and keep going
  • have winds ranging from 65 to about 300mph
  • Often have a condensation funnel.

WEEK 24:
Question: How does a tsunami develop?

Answer: The principal generation mechanism (or cause) of a tsunami is the displacement of a substantial volume of water or perturbation of the sea. This displacement of water is usually attributed to either earthquakes, landslides, volcanic eruptions, or more rarely by meteorites and nuclear tests. The waves formed in this way are then sustained by gravity.

WEEK 25:
Question: What happens when a cold front meets a warm front?

Answer: A cold front advancing on a warmer air mass will force the warm air mass upward (cold air sinks and hot air rises).

The warm air rushes quickly upward causing rapid cooling and condensation of water vapor. In summer, thunderstorms will often accompany fast-rising warm air; in winter, a snowstorm can form.

Once the cold front has pushed its way under the warm air, the surface temperature in that region will drop sharply.

WEEK 26:
Question: How is a raindrop formed?

Answer: The clouds floating overhead contain water vapor and cloud droplets, which are small drops of condensed water. These droplets are way too small to fall as precipitation, but they are large enough to form visible clouds. Water is continually evaporating and condensing in the sky. For precipitation to happen, first tiny water droplets must condense on even tinier dust, salt, or smoke particles, which act as a nucleus. Water droplets may grow as a result of additional condensation of water vapor when the particles collide. If enough collisions occur to produce a droplet with a fall velocity which exceeds the cloud updraft speed, then it will fall out of the cloud as precipitation.

WEEK 27:
Question: Does hail always come before a tornado?

Answer: Not necessarily.  Hail characteristics vary from storm to storm. While large hail can indicate the presence of an unusually dangerous thunderstorm, and can happen before a tornado, don't depend on it. Hail is not a reliable predictor of tornado threat.

WEEK 28:
Question: What's the difference between a water spout and a tornado?

Answer: A waterspout is a tornado over water--usually meaning non-supercell tornadoes over water. Waterspouts are common along the southeast U.S. coast--especially off southern Florida and the Keys--and can happen over seas, bays and lakes worldwide. Although waterspouts are always tornadoes by definition; they don't officially count in tornado records unless they hit land. They are smaller and weaker than the most intense Great Plains tornadoes, but still can be quite dangerous. Waterspouts can overturn boats, damage larger ships, do significant damage when hitting land, and kill people. The National Weather Service will often issue special marine warnings when waterspouts are likely or have been sighted over coastal waters, or tornado warnings when waterspouts can move onshore.

WEEK 29:
Question: Do volcanoes affect weather?

Answer: Yes. For example the June 1991 eruption of Mount Pinatubo was global. The sulfur dioxide (SO2) in the cloud -- about 22 million tons -- combined with water to form droplets of sulfuric acid, blocking some of the sunlight from reaching the Earth and thereby cooling temperatures in some regions by as much as 0.5 degrees Celsius. A similar phenomenon occurred in April of 1815 with the cataclysmic eruption of Tambora Volcano in Indonesia, the most powerful eruption in recorded history. Tambora's volcanic cloud lowered global temperatures by as much as 3 degrees Celcius. Even a year after the eruption, most of the northern hemisphere experienced sharply cooler temperatures during the summer months. In parts of Europe and in North America, 1816 was known as "the year without a summer."

WEEK 30:
Question: What conditions cause hail to develop?

Answer: In the past, the prevailing thought was that hailstones grow by colliding with super cooled water drops. Supercooled water will freeze on contact with ice crystals, frozen rain drops, dust or some other nuclei. Thunderstorms that have a strong updraft keep lifting the hailstones up to the top of the cloud where they encounter more supercooled water and continue to grow. The hail falls when the thunderstorm's updraft can no longer support the weight of the ice or the updraft weakens. The stronger the updraft the larger the hailstone can grow.

WEEK 31:
What causes the colors in the rainbow?

Rainbows are caused by the splitting of white sunlight into it component colors by raindrops. Some of the light that falls on a water drop enters the drop. As it enters the drop, the color components of the sunlight are refracted (bent) by different amounts depending upon their wavelength (we perceive the different wavelengths as different colors.)

Then, the different colors reflect off the back of the inside of the drop, and when they pass through the front of the drop again, they are refracted once again.

More: 2009 Weather in the Classroom Questions and Answers