Weekly Weather Question Answers

Tuesday, September 8th 2009, 12:14 pm
By: News On 6

Why is the sky blue?

Answer: The sky is blue is because of the scattering of light by the atmosphere.

Why are there thunderstorms every day?

Answer: Storms form due to lift in the atmosphere, moisture, and instability.

What is El Nino?

Answer: El Nino is a weather phenomenon that describes the slight periodic warming of normally cold ocean currents in the equatorial and tropical pacific. 

El Niño means "the boy" in Spanish, and usually refers to the Christ Child, due to this phenomena being first noticed by local residents off coastal regions during the month of December.

Major periods of El Nino may occur every 5 to 7 years.  The opposite effect or a slight cooling of oceanic sea surface temperatures can also occur and is referred to as "La Nina or "the girl". La Nina may also occur in major instances every 5 to 7 years. 

These small but important temperature changes may have significant impacts on global weather patterns, including the weather in Oklahoma and the United States. The slight warming of the usually cold ocean currents can have devastating impacts on foreign fishing economies, such as the anchovy market off the Peruvian coastline. 

The exact cause of El Nino and La Nina are still unknown, but scientist and researchers continue to explore this fascinating part of our climate.

What is Dew and how does it form?

Answer: Dew is small water droplets that form on ground level, usually during early morning or late evening hours.  Dew is formed as the surface temperature drops to the dew point temperature and relative humidity increases. 

Unlike rain that falls from the sky, dew forms at the ground. 

As warm air escapes the earth's atmosphere during overnight hours under clear sky, the temperature begins to fall. 

The dew point is the actual temperature at which the water vapor will condense.  As the temperature falls, the dew forms.  The dew doesn't last long and is usually gone as temperatures begin warming during the early morning hours and relatively humidity decreases.

What causes Frost?

Answer: Frost is caused by water vapor freezing on objects either on the ground or close to the surface. 

The frost process is similar to how dew forms, but the temperature of the ground level air or object must be at or below freezing and colder than the frost point of the layer of air slightly above the surface. This allows the water vapor to freeze and form on the exposed objects  as it goes directly from vapor to a frozen state. 

The frost can cover the ground, car windows, roof tops, and other items.  The actual frost will resemble small crystal like patterns.

What causes fog?

Answer: Fog is water vapor or moisture that has condensed to form a cloud on or near the ground. 

Fog begins forming as the surface temperature falls closer to the local dew point temperature and relative humidity increases.

The air becomes saturated and the fog begins to form. 

Fog may also form near or over bodies of water, and may also form as warm moist air rises over a relatively cold surface such as snow.

WEEK 7: 
What causes hail?

Answer: Hail is formed by strong updraft currents in thunderstorms.  As thunderstorm clouds begin to grow, ice crystals will also grow in portions of the cloud. 

The ice crystals begin to fall but the strong updrafts will catch the ice and keep it suspended in the cloud.  This crystal then begins falling, but once again, the updraft stops the crystal from falling completely to the ground. 

A cycle develops with the ice crystal becoming larger each time this trip takes place.  Eventually the ice becomes too large for the updraft to support and it falls to the ground as hail. 

Large hail means a powerful updraft has completed this hail growth cycle many times.

What causes a flood?

Answer: A flood occurs when too much rain falls too quickly, or when it rains for a very long time.

What is Ozone?

Answer: Ozone is a colorless gas made up of oxygen molecules.

Ozone in the lower layer of the atmosphere is generally considered harmful and can promote pollution and smog.  High levels of ground level ozone can lead to breathing difficulties in people with respiratory problems.

Ozone in the upper portion of the atmosphere is considered good and helpful and keeps extremely harmful ultraviolet rays from impacting the earth.

WEEK 10:
What is wind chill?

Answer: The wind chill temperature describes how cold it is to exposed skin while outside.

WEEK 11:
What causes the seasons to change?

Answer: The different seasons result from the earth revolving around the sun, and the tilt of the earth as it relates to the sun during the year long orbit.  The earth is tilted 23.5 degrees on an axis relative to the sun. This results in a sun angle change during the year as the earth revolves around the sun.  

A low sun angle is experienced during the northern hemisphere winter, and a high sun angle is experienced in the northern hemisphere summer. 

It may surprise you to learn the earth is actually closer to the Sun during our winter and farther away from the sun during our summer. 

WEEK 12:
What is the wettest year on record in NE Oklahoma?

Answer: The year was 1973 and the amount of precipitation for 1973 was 69.88 inches.

WEEK 13:
What is a blizzard?

Answer: A blizzard is a name for a snow storm that will produce sustained winds up to 35 mph or greater. 

A blizzard produces falling or blowing snow reducing visibility to less than a quarter of a mile. 

These conditions are expected to last for at least three hours or more before a blizzard warning would be issued by the National Weather Service.

WEEK 14: 
Why is some hail bigger than others?

Answer: Hail stones size depends upon the strength of the thunderstorm updraft. 

As the speed of the updraft increases, the size of the hail stone will also increase. 

Pea size hail represents updraft winds around 20 mph, but golf ball stones may represent updraft speeds approaching 100 mph.

WEEK 15:
Why are some snowflakes shaped differently than others?

Answer: Snowflakes can come in different shapes and sizes, but all of them have 6 sides. 

The exact shape depends upon temperature and moisture content.  Colder temperatures usually produce smaller crystals.  

Snow crystals can be relatively flat, appear like needles, or can be small columns.

WEEK 16: 
What is the composition of air?

Answer: Dry air is mainly nitrogen and oxygen.  The remaining portion of the atmosphere is composed of argon, carbon dioxide, and other trace gases. 

Water vapor also makes up a small variable portion of the atmosphere.

Most of the atmosphere is composed of:
Nitrogen 78%
Oxygen 21%
The other trace gases make up the remaining 1% of the air.

WEEK 17:
What is a Microburst?

Answer:  A microburst is a downburst of damaging wind from a thunderstorm.

The term microburst is used to describe wind damage over a few hundred yards or up to 2 miles wide.

The term macro burst is used if a larger area is impacted. A dry microburst involves very little precipitation, and a wet microburst describes a damaging rush of wind and rain.

Both of these involve powerful downdrafts of air rushing from the storm to the surface.

WEEK 18:
What is a gust front?

Answer: A gust front is the leading edge of cool air rushing down or out of a thunderstorm.

Gust fronts usually have a sudden wind shift followed by sharply cooler temperatures.

WEEK 19:
What's the difference between high and low pressure?

Answer: High pressure represents sinking dense air and is common with fair weather. 

Low pressure represents rising light air and is common with unsettled or stormy weather.

The letter 'H' represents areas of high pressure at the surface on a weather map and the letter 'L' represents surface areas of low pressure on weather maps.

WEEK 20: 
How are hurricanes named?

Answer: I found this excellent answer from the National Hurricane Center's web site. 

'Since 1953, Atlantic tropical storms have been named from lists originated by the National Hurricane Center.

They are now maintained and updated by an international committee of the World Meteorological Organization.

The original name lists featured only women's names.

In 1979, men's names were introduced and they alternate with the women's names.

Six lists are used in rotation. Thus, the 2009 list will be used again in 2015.'

WEEK 21:
Why do clouds appear dark and gray?

Answer: Clouds appear dark when they block out sunlight.

Cloud particles can reflect sunlight but if clouds are thick enough, they absorb sunlight and appear dark and gray.

WEEK 22:
What are straight line winds?

Answer: Straight line wind usually refer to strong or severe wind rushing out from a thunderstorm or gust front and is not associated with a tornado.

The term is used many times to describe damaging winds not caused by a tornado.

WEEK 23: 
Why some clouds gray and others are dark?

Answer: The color of the cloud depends upon the optical thickness of the cloud. 

Clouds with large amounts of water droplets don't allow light to pass through or penetrate the cloud and the cloud appears dark or gray. 

Thin clouds or clouds with very little water droplets can reflect sunlight better and sunlight is able to penetrate or pass through the cloud allow the cloud to appear white. 

WEEK 24:
What tools are used to forecast weather?

Answer: There are many tools used to forecast the weather, but most of them fall into one of the 4 basic categories.  1. The observation network.  2. Satellite and Radar. 3. Computer Model Data and 4. Experience

WEEK 25:
What's the difference between dew point and relative humidity?

Answer: The dew point is a measure of the moisture in the air expressed as a temperature.

The relative humidity is a measure of the amounts of moisture relative to the temperature and dew point temperature.

WEEK 26:
Why are there no hurricanes in Oklahoma?

Answer: Oklahoma is landlocked and too far removed from oceanic influence to experience a hurricane. 

Remnants of tropical storms and depressions have impacted the state resulting in tornadoes and flooding rainfall.