Constant pressure analysis chart

rcaligan

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rcaligan
(Cross-post from red board).

I'll admit, being a low-level flyer I've never had a use for this chart, but I need to teach it soon. I'm having a tough time figuring out what useful information this chart gives a pilot. The whole hecto-pascal/millibar/meters thing is throwing me off, too.

For you more sage teachers & pilots out there, how would you teach this chart to someone earning an instrument rating?
 

Skipp,

Thanks. I'd already looked over the AC and while it gave a lot of information, it seemed rather sterile, so to speak. You can tell it was written by a meteorologist and not a pilot. Plus, the product on aviationweather.gov looks different from what's shown in the AC.

I'd like to teach it from a pilot's perspective...
1. This is what it's good for
2. This is how you get it
3. This is how you read it
 
(Cross-post from red board).

I'll admit, being a low-level flyer I've never had a use for this chart, but I need to teach it soon. I'm having a tough time figuring out what useful information this chart gives a pilot. The whole hecto-pascal/millibar/meters thing is throwing me off, too.

For you more sage teachers & pilots out there, how would you teach this chart to someone earning an instrument rating?

Scott's got some good info on one use of the CPC in this article:

http://chesavtraining.com/Articles/Dennstaedt_Blocking.pdf

Also, from an AOPA weather article:

Conditions aloft. All of the ingredients for a vengeful cold front may be in place at the surface, but if there's no lifting force aloft, cold fronts won't intensify to impressive levels.

On a 500-millibar constant pressure chart (this represents an altitude of approximately 18,000 feet msl), look for troughs — southward bends in the height contours depicted on these charts. Troughs provide lift for unstable air beneath them. Find the southeast quadrant of the trough. That's where the maximum lifting forces usually are located. If there's not a front or storm complex beneath this part of the trough, there probably soon will be. If you can't obtain a 500-millibar chart, ask a briefer to describe any troughs that he might see on his copies.
 
Last edited:
Thanks all! Between the responses posted on here and the red board, I've learned a lot and feel a lot more comfortable.
 
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