Scaffolded notes
Build the idea
Jet streams are fast upper-air currents
Jet streams are relatively narrow bands of strong wind near the top of the troposphere. They generally flow west to east but form waves. Strong temperature differences across a boundary can support a stronger jet.
Ridges and troughs redirect air
A northward bulge is commonly called a ridge and is often associated with warmer air beneath it. A southward dip is a trough and often brings cooler air farther south. The pattern can move, deepen, weaken, or stall.
The jet helps steer systems
Surface lows, fronts, and storm tracks are influenced by upper-level winds. Meteorologists use satellite water-vapor imagery and upper-air observations to locate the jet stream. A system separated from the main flow may move slowly, increasing the chance of prolonged heat or rain.
Stop and explain
Check your thinking
1. What creates or strengthens major jet-stream temperature gradients?
Possible response: Strong contrasts between warm and cold air masses.
2. How can a stalled upper-air pattern affect hazards?
Possible response: It can prolong heat, drought, or repeated rainfall and flooding.
Interactive challenge
Try the science
A deep jet-stream trough moves over the eastern United States. Which change is most plausible?
Before you leave
Exit ticket
Explain one way the jet stream influences North Carolina weather.