Heat Bubble
Everyone knows that rural temperatures are often lower than city temps. Sometimes when the air temperature is near the dewpoint the effects of local heating caused by cities are noticeable in differences of condensation. When that condensation is rain and is visible on radar then we get a radar image of a heat bubble. That heat bubble is always there, it’s just not always visible. It’s caused by things like cars and trucks, heat leaking from buildings, and sun on asphalt and concrete.
In the radar image below is from late last week the area without the rain in the middle is warmer by just enough to stop the formation of the rain. Multiply the heat effect of Washington DC below by all the cities in the world, and you can get some massively large effects.
