A hodograph is a plot that connects the tips of wind vectors from a stack of levels into a single curve, so the way wind speed and direction change with height shows up as one continuous shape rather than a table of numbers. Each point on the curve is one level's wind, drawn from the origin, with heights usually color-coded so the surface, 1 km, 3 km, and 6 km levels are easy to pick out.
What the shape is telling you
The straight-line distance between two heights on a hodograph is the vector wind shear across that layer. A long segment from the surface to 6 km means strong deep-layer shear, which is one of the classic ingredients for supercell organization. A short segment means the flow through that layer is nearly uniform and shear is weak.
The curvature matters as much as the length. When the curve bends counterclockwise or clockwise as you climb, it indicates that the wind direction is turning with height. In the Northern Hemisphere, a clockwise-turning hodograph in the low levels favors right-moving supercells and is associated with streamwise vorticity, the horizontal spin oriented along the flow that a rising updraft can tilt into vertical rotation.
Storm-relative helicity, or SRH, is the swept area between the hodograph and the storm motion vector across a chosen depth. Larger swept areas mean more streamwise vorticity for a storm to ingest, which is why forecasters draw storm motion on the plot and look at the resulting shape rather than the ground-relative curve alone.
How forecasters read one
A quick read starts with three questions. Is the surface-to-6 km shear long enough to support organized cells, roughly 35 to 40 knots or more as a common working guide. Does the low-level curve show meaningful clockwise turning between the surface and 1 km. And is the storm motion vector oriented so that the low-level curve wraps around it, which is what generates large 0 to 1 km SRH.
The critical angle, the angle between the surface-to-500 m shear vector and the storm-relative surface wind, is a further refinement. Values near 90 degrees maximize the streamwise fraction of the near-surface vorticity, which some studies associate with an increased tornado threat in an already supercell-favorable environment.
Important limits
A hodograph is one profile at one point in time. Real environments evolve through the day, boundaries locally back the low-level flow, and the wind profile a storm actually ingests can differ significantly from the nearest sounding.
SRH also depends on the storm motion vector, and predicted motion can be wrong. A right-moving supercell that instead moves with the mean wind sweeps a very different area under the same curve, and the diagnosed helicity changes accordingly. Treat any single hodograph as a hypothesis about the environment, and cross-check it against surface obs, VAD wind profiles, and model soundings before leaning on it.