An Introduction to Hodographs

An Introduction to Hodographs

Hodographs are oftentimes misunderstood amongst newer storm chasers or weather enthusiasts. These charts can be daunting but they aren’t as complicated as you fear, at least the basics.

A hodograph is, simply put, a graph which plots wind speed and direction with height. They can be confusing, but watch our intro video to get a basic idea about how they work:

How Hodographs Work

A hodograph is simple, and de-mystifying them for beginners is what this lesson is all about.

Let’s check out a sample hodograph.

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The chart above may look confusing — but let’s break down what its showing.

  • Bold black lines intersecting in the middle: These show wind direction. Almost always up is north, down is south, etc.
  • Concentric Circles: The concentric circles circling the center are used to denote speed of winds. Typically the numbers indicate wind speed in knots. Remember, 1 knot = 1.15078 m.p.h.

And that’s it!

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In the sample above, I’ve plotted out a surface wind speed out of the SE at 18kts. The key part to remember about the chart is that winds are plotted from the center and not in the direction from which winds are blowing.

A real world example is if you stand where both black lines intersect in the middle and let go of a balloon, the hodograph will which way and how far it will fly as it goes up.

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In this example, the winds are out of the southeast at 18kts near the surface and gradually veer with height.

  • Surface speed: SE at 18kts.
  • 850mb speed: SSE at 30kts.
  • 700mb speed: SSW at 39kts.
  • 500mb speed: WSW at 48kts.

Yes I couldn’t help myself but to draw near perfect supercell shear.

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One last way to think about this is if you plotted out winds with arrows from the center, this is what you’d get.

They’re That Simple

So that’s the 101 level introduction to hodographs. Stay tuned as we get ready to do more lessons on how to read these charts!

See More: Introduction to Skew-Ts

By |2019-02-16T11:32:21-06:00February 20th, 2019|Blog, Our Photos and Videos, Storm Chase Forecasting, Titan U|0 Comments

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