Some Meteorology Questions

[WeatherFanMatt]

Hello, everyone. I'm still learning meteorology myself, and as just an enthusiast, I would like to get to know more from actual meteorologists, or the more knowledgeable about Meteorology. (I'm just 14)

 

1. My first question is, I'm tracking a cold front on it's way south. Why isn't it creating a long band of rain or clouds? Is it because the air mass the front is running into, is not hot enough? Because we had a cold front sweep through a few days earlier. Or is it because the high pressure over the south east?

 

I would post a picture, but It's not letting me. Says the image extension is invalid, must I upload to another site?

 

2. If the dew point is equal/near to the air temperature, will this spawn clouds? Must the humidity be high, must be pressure high/low?

 

Thank you

[WxJordan]

First Question:

For the first question, there could be a couple of explanations. A cold front is a boundary that separates two different types of air masses. If the cold front is diving south quickly, it may not have enough time to pick up moisture from some source to be able to produce clouds and showers. It could also be that the air in front of the cold front is not moist enough to cause any showers.

In the winter in the southeast, sometimes we have a cold front pass through the area that has a lot of rain associated with it; however, it does not have a major temperature drop behind it. These fronts are usually moving slower and are able to tap into moisture from the Gulf of Mexico. After this cold front passes, temperatures drop slightly; however, you notice that the dew points plummet behind the front. About 24 hours later, we may get a second cold front to pass through. This front is moving into an area with already lower dew points, so only few clouds may be produced; however, there is very little precipitation because the moisture content is low.

 

Second Question:

Clouds are formed by condensation of water vapor through lifting an air parcel upward or cooing the air. So if the dew point and temperature are close to each other, it may cause fog to form at the ground; however, it does not mean there will be clouds forming above ground level. (I am not sure if by saying clouds you are talking about clouds in the sky like cumulus and stratus or fog, which is also a cloud). Usually, to get fog to form, you need a very humid air mass and a high pressure, because you need very little wind in most cases, except in cases of advection fog. Clouds forming above the ground and producing precipitation have relative humidity values slightly greater than 100%.

Clouds are most likely ahead of areas of low pressure where there is lots of moisture surging northward; however, you can have pockets of clouds with high pressure areas when there are upper level disturbances and other features moving by.

 

I hope I have answered your questions. Please let me know if you have any more questions.

[Thunder Road]

Fyi, there is an entire subforum dedicated to introductory questions!

 

http://www.americanwx.com/bb/index.php/forum/30-meteorology-101/

 

This thread will probably be moved there soon.

 

Keep working hard, and good luck!