The division of the geologic time scale that represents the longest time span is called a(n)

An eon

Explanation:

The first broad division of the geologic timescale is the eon. Others are Eras, Periods and Epoch.

Eons are the most broad and the largest of divisions of the timescale. There are two categories of the eons which are:

The Phanerozoic eon is the most recent. The Hadean eon is the is the oldest eon.

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.