🔍 Key Concepts

• Prevailing westerlies in mid-latitudes • General movement of low-pressure systems across North America • How weather maps show storm tracks over the U.S. and Canada

💭 Think About

• Think about the usual track of major storms you see on national weather forecasts—what side of the continent do they usually form or appear on, and which way do they travel? • Consider the typical direction airplanes take longer to fly versus shorter (jet streams) when crossing the U.S.—what does that tell you about upper-level winds? • Recall that North America’s mid-latitudes are dominated by certain prevailing winds; how do those winds tend to blow?

✅ Before You Answer

• Make sure you are thinking about most common large-scale systems, not local sea breezes or tropical storms only • Focus on mid-latitude weather patterns where most U.S. ports and shipping lanes are, not polar regions • Visualize a surface weather map of the U.S. and note which way the L (low) and H (high) systems usually travel over several days