Friday, November 14, 2008

Weather Fronts -- More Than You May Want To Know

Well we've been discussing air masses over the past few blogs, and yesterday I told you a front is the "front-line" so to speak of these air masses.

Today we'll start learning more about fronts.

Cold fronts, stationary fronts, warm fronts, back door cold fronts, occluded may have never realized there are so many terms out there.

It all just depends on what is happening at the boundary between two air masses.

Let's start with a stationary front.

This is just a front that has no movement. Neither air mass is strong enough to overtake the other.

Waves of lower pressure, or disturbances, may ride along the front bringing unsettled weather to a region, sometimes for several days.

Eventually either the two air masse kind of just equal out and blend into one another, sometimes described by a t.v. weatherman as the front "washing out".

Or other times a new weather system may come along and give one air mass the strength it needs to push on and win the battle.

On a colored weather map, the stationary front is drawn as an alternating red and blue line.

The semicircles point toward the colder air on the red line.

The triangles point toward the warmer air on the blue line.

(Kind of opposite of what one might think -- welcome to meteorology!!)

Winds at the surface tend to blow parallel to the stationary front, and in opposite direction on either side of it.

Up above in the atmosphere, winds also tend to blow parallel to the front.

(Remember you now have to think 3-D -- the cold front extends from the surface up into the atmosphere)

Monday we will talk about the types of weather you can expect along a stationary front.

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