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Why does weather change more often in the mid-latitudes than in tropical regions?

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Weather forecasting Doppler radars, such as this one operated by the U.S. National Weather Service at New Underwood, South Dakota, extract the Doppler frequency shift of the echo produced by a moving target by noting how much the frequency of the received signal differs from the frequency of the signal that was transmitted.

Weather changes more frequently in the mid-latitudes than in tropical regions primarily due to the presence of the polar front, a dynamic transition zone between cold, dense polar air and warm, buoyant tropical air.12

In the mid-latitudes, this large thermal contrast creates a significant pressure gradient that fuels the development and movement of extratropical cyclones and associated cold fronts and warm fronts. These systems are responsible for the variable weather, cloudiness, and precipitation characteristic of these regions. The jet stream, which is strongest where these air masses meet, further influences the intensity and path of these storm systems.12

Conversely, tropical weather is largely governed by the Hadley cell, a persistent circulation pattern that results in more stable, predictable conditions. While the intertropical convergence zone drives convective rainfall, the tropics lack the frequent, large-scale frontal interactions between contrasting air masses that drive the rapid, day-to-day weather fluctuations seen in the mid-latitudes.34