Why are most of the capitals of Europe on major rivers?

Most of the world's major cities were built on or around areas of freshwater. Our ancestors chose to settle near these areas as rivers were a means of supplying drinking water for their families and beasts, as a food supply, used for irrigating crops, and as a means of transport in order to aid commerce.

i would expect light rain in pittsburgh throughout the following 24 to 48 hours. the lower/falling weights in urban areas toward the west demonstrate that a low weight framework is moving from west to east toward pittsburgh. low weight frameworks are ordinarily connected with precipitation. the way that you don't see a major drop in temperature in the more western urban areas demonstrates the low weight framework is moving with a warm front, so just light rain would be normal. substantial downpours or progressively vicious climate is just typically connected with chilly fronts, where the warm air is pushed up and over a cool front quickly. this quickly rising air (convection) is what gives you heavier torrential downpours, and other conceivably serious weather conditions.