Does a Full or New Moon Change the Weather?

Weather Talk

POSTED: Monday, February 17, 2014 - 1:42pm

UPDATED: Monday, February 17, 2014 - 1:51pm

Is there More or Less Rain and Do the Temperatures Drop or Rise?

We had a full moon this past Friday, on Valentine’s Day. The atmosphere was full of love that night, but I was wondering if the full moon has an effect on our atmosphere as well. I know in meteorology we always refer to the atmosphere as “an ocean of air”. The air behaves very much like water. We do know that the moon and its gravitational pull do affect high and low tides of the oceans and large bodies of water. So I thought I would investigate the effect of full or new moons on our weather in today’s "Weather Talk”.

Tides are created because the Earth and the moon are attracted to each other, just like magnets are attracted to each other. The moon tries to pull at anything on the Earth to bring it closer. But, the Earth is able to hold onto everything except the water. Since the water is always moving, the Earth cannot hold onto it, and the moon is able to pull at it. Each day, there are two high tides and two low tides. The ocean is constantly moving from high tide to low tide, and then back to high tide. There is about 12 hours and 25 minutes between the two high tides.

Tides are the periodic rise and falling of large bodies of water. Winds and currents move the surface water causing waves. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, two tides occur each day.

When the sun and moon are aligned, there are exceptionally strong gravitational forces, causing very high and very low tides which are called spring tides, though they have nothing to do with the season. When the sun and moon are not aligned, the gravitational forces cancel each other out, and the tides are not as dramatically high and low. These are called neap tides.

Spring tides occur during the full moon and the new moon. When the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. This is known as a spring high tide. Spring tides are especially strong tides (they do not have anything to do with the season spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides.
Now we know that there is a proven impact on the water, what about the weather?

Elizabeth Merriam, eHow.com Contributor wraps it all up like this;
Atmospheric Tides
The atmosphere is subject to the same tidal forces as the oceans, although to a much lesser extent. Gases are less responsive to tidal forces because they are so much less dense than water. These tides affect atmospheric pressure, a well-known factor in weather systems. However, the increase in atmospheric pressure which can be detected at the front edge of the tidal wave is so small it is thought to be overwhelmed by other factors.
How the Moon Affects the Weather
The moon affects the weather in several indirect ways. The moon has a large effect on ocean tides, and tides have a significant effect on the weather in the sense that a world without a moon would experience little or no tides and would have a different system of weather. The moon also has a small effect on polar temperatures.
Tidal Effect
Since the moon's gravitational force depends on distance, at any given time, the portion of the Earth closest to the moon (i.e.., directly underneath it) is most strongly influenced by gravity. This means that when the moon is over an ocean, the water is pulled toward it, creating what is called the tidal bulge. As the moon orbits the Earth, the tidal bulge acts like a wave sweeping around the Earth. This effect causes the tides.
Ocean Tides
Generally, two low tides and two high tides occur in every 24 hour period, about 50 minutes later each day. During the new moon and full moon, high tides are higher and low tides lower than normal. During the first and last quarter moon, high and low tides are more moderate than normal. Tides affect the movement of ocean currents, which affect the weather through the amount of warming or cooling water moving through a given area. For example, water temperature combines with wind strength and direction to define the duration and strength of weather events like the El Niño.
Atmospheric Tides
The atmosphere is subject to the same tidal forces as the oceans, although to a much lesser extent. Gases are less responsive to tidal forces because they are so much less dense than water. These tides affect atmospheric pressure, a well-known factor in weather systems. However, the increase in atmospheric pressure which can be detected at the front edge of the tidal wave is so small it is thought to be overwhelmed by other factors.
Polar Temperature
Satellite measurements of the temperature of the atmosphere shows that the poles are 0.55 degrees Celsius (0.99 degrees Fahrenheit) warmer during a full moon than during a new moon. Measurements show no effect on temperatures in the tropics, but the temperature around the globe is on average 0.02 degrees Celsius (0.036 degrees Fahrenheit) higher during the full moon. These small temperature changes have a slight but measurable affect on the weather.

Martha White gathered some weather folklore for the “Old Farmer’s Almanac”;
Farmers, sailors, and other sky watchers have long used the Moon to predict the weather.
The next time that you look up at the Moon, consider this weather-related folklore:
In the wane of the Moon, a cloudy morning bodes a fair afternoon.
• If the crescent Moon holds its points upward, able to contain water, it predicts a dry spell.
• If the new Moon stands on its points, expect precipitation to spill out.
• A winter full Moon is a time for long cold snaps.
• A full Moon in April brings frost.
• Sailors agree that the full Moon "eats clouds."
• Two full Moons in a month increase the chances of flood.
• A pale full Moon indicates rain, while a red one brings wind.
• A Christmas full Moon predicts a poor harvest.
• The days following a new Moon or a full Moon are typically stormy.

Know we know the full or new moon does impact the tides oceans, which impact the weather. We also discovered that the full or new moon causes waves in our atmosphere as well and that during a full moon there is a small warming effect of the polar temperatures and an even smaller warming effect worldwide. The full moon causes waves and warms which both impact our weather. All the weather folklore is different depending on the region or where you are in the world. I now think that some of the many centuries and decades of farmer’s,sailor’s and sky watcher's sayings may have a bit of truth to them. Check out my previous “Weather Talk”; Some Weather "Folklore" Is True http://www.ktsm.com/weather/weather-talk/some-weather-folklore-true

Chuck DeBroder, Chief Meteorologist
KTSM, NewsChannel 9, NBC, El Paso, TX
cdebroder@ktsm.com
www.facebook.com/Charles-DeBroder
www.twitter.com/ Chuck DeBroder NC9 @wxchuckNC9
 

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