BLOG: Here comes a wedge this week…  a what?

BLOG: Here comes a wedge this week…  a what?

CHARLOTTE, NC (WBTV) - You are likely to hear at least one of us attribute this week's cloudy and cool pattern to a wedge.

So what the heck is that? A wedge describes what the pressure field looks like across our region as a surface high builds to our north and pinches into the Carolina Piedmont causing a cool, but damp northeast flow off the Atlantic Ocean.

See the accompanying picture. Notice how the wind flow (which parallels the pressure field) looks like a wedge along the eastern slopes of the Appalachians.

You will also hear "wedges" referred to as cool-air-damming events. That is because the cool air rolling in from the east hits the mountains and has no place to go. The mountains act like a dam and trap the cool air which then pools over western and central North Carolina.

But wait, it gets better. Cool air is denser than warm air, so as the cool air piles up, its weight forces the pressure to rise and actually reinforces the wedge already in place.

That is why these patterns are often times difficult to break. And this one may be no different as our weather could be influenced by this latest one for another week or more!

The telltale byproduct of wedges are mainly cloudy skies with cool damp air and patchy light rain or drizzle. The rain is typically not heavy, and certainly can't be counted on to help our drought much.

You can also get thunderstorms with wedges. They are most common around the wedge's outer boundary to the south and east, but in some cases they can develop in the air above the wedge.

People are often taken by surprise with those since you can find yourself in the middle of a thunderstorm and the temperature is 58° outside!

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